BA038 (B777) Thread

[sky9]

I have always wondered whether bringing up the flaps to G/A configuration would have significantly changed the outcome, Vref 30 +5 being roughly the same as V2 flap 20.
( I write this as a retd 767 Capt with no experience of the 777). Has anyone done an in-depth analysis of various scenarios in the sim? If not it should have been done as the situation was outside any QRH action so walking away was a success whatever they did.

[WojtekSz]

SFLY - i like your perseverance ;) - so lets follow your suggested way and imagine we would like to fly best gliding speed ie closer to Vref

How could it be achieved (let us know if you see any other way):
I understand that we are talking about last 20 seconds of flight, right from the moment when the crew has realized that there is really no thrust available (some 3..4 secs after second attempt to add full thrust), with the speed already well below Vref (currently 115kt=59m/sec) and the nose quite high (8deg), clearly below intended GP (300ft=91m above ground), F30, gear down, ac weight about 200tons, with current vertical speed of 600ft/min(=3m/sec) - with this speed our max time in the air would be less than 30 sec:

so to reach Vref we need to accelerate the plane, the best way is to use some existing potential energy to gain vertical speed and than use wings to change it into horizontal speed: not to get into too much teory lets look how long it took and much speed was gained when finaly PF lowered the nose: within 8 sec the plain gained 1kt (sic) and the vertical speed has doubled ! If he would have lowered the nose more he would have gained more speed - but would he have time to get back to level flight?

SFLY be reasonable - would you really like to fly the plane using this strategy?

And look what the crew did: they used whatever kinetic energy was there to stay as high and for as long as possible. At the last moment they went for speed to regain ac maneuverability and just landed (not crashed).

Actually it is the same trick all young pilots instinctively try to do when get below ILS and forget to use the engine throttle :)

[wilyflier]

Pardon me, I still hear my instructor saying "Dont stretch the Glide"

[S.F.L.Y]

WojtekSz (http://www.pprune.org/members/305447-wojteksz), the funny thing between us is that we never understand each other. I'm sorry to say that you're conception of gliding and dead stick landing is wrong and dangerous.

Was you quoted was more a general/theory remark and I didn't say they should have dived to get back to Vref. My point was to say that speed control is crucial and if not increasing speed by diving, they certainly shouldn't have let it drop too low.

Maintaining best glide speed and retracting flaps is only the first step of a dead stick lading. When you get closer to the ground flaps can be selected (and speed finally reduced) to stretch the path in a long flare. But if you're not touching down at the end of this flare you just fall like a stone...

You said they were below intended GP, which is wrong, they were on the ILS GP which is above the best glide path.

Flaps were selected 25 some 20 s before AP disconnection, at 118 kts. I'm not saying they had time to accelerate to 135 kts and subsequently flare. I'm wondering prevented the AP to be disconnected at the same time flaps were selected 25, which would have given 20 more seconds to control a more reasonable speed (118 kts instead of 100 kts) at a much lower AoA.

Should the AP had been disconnected earlier the PF wouldn't had to make the nose down input you've mentioned. This was achieved because the aircraft was stalling. Keeping away from stick-shaker wouldn't require such actions. While I'm saying speed is essential it doesn't mean you have to accelerate when you don't have time, but disconnecting the AP simultaneously with the selection of flaps 25 would allow you to fly around 120 kts which is definitely increasing the gliding distance and giving a lot more of flare energy to control the impact Vz.

To me both actions on flaps and AP should come together, and I'm wondering why 20 seconds and 18 kts were lost.

By the way, lowering the nose by 1 degrees at 118 kts will give you much more acceleration and less Vz increase than at 100 kts... you just can't use this example to quantify the benefits of such inputs at different speeds.

[WojtekSz]

wilyflier:
your instructor was absolutely right!
the same applied possibly to your chemistry teacher who used to tell you: remember to pour acid into the water!
these are the golden rules which should be generally obeyed - especially by people who do not have the deep knowledge and experience.
As you would probably agree there are always exceptions to general rules, and these exceptions are being sometimes used to the user advantage.

And i am not talking here about speed limit being sometimes overstreched by all of us being experienced drivers := even if we all know that dangerous speed kills.

[BOAC]

Pardon me, I still hear my instructor saying "Dont stretch the Glide" - away from ANY comment on this crew's action - while your instructor was teaching you a good basic tenet - as I commented many moons ago (I think on the original 038 thread) that 'rule' should be treated with commonsense. If you are at best L/D with, say, 10 kts in hand over the stall at 50' in your Cessna and you are faced with a wall in front of you, using some of those 10 kts to 'skim' over the wall is fine. If however you have the same +10 kts at 1000' it is a bad idea. After all, what is the landing flare but effectively a 'stretch of the glide', with the wheels meeting the runway as the a/c runs out of enthusiasm for 'flying'?

It takes us back to the eternal 'Habsheim' argument as to whether an 'iron' a/c such as 737 would have had enough energy to just clear the trees without stalling unlike the AB with its alpha-floor protection which limited its climb = no trees, no crash..

There never will be an answer to that conundrum (and I am certainly not intending we should open this again!) nor to whether to trade speed for distance at some lower height. It all comes back to what I and Woodpecker described as that 'sixth sense or 'seat of the pants' which can only come with experience.

[WojtekSz]

i tried to compile my own answer to the problem presented by SFLY and when searching for B77 stall speed numbers i have found all the answers already there.

an executive summary:
FullWings (http://www.pprune.org/members/80116-fullwings): I think this discussion shows that you can't write SOPs for every conceivable occurrence and that Airmanship is thankfully still alive and well in some quarters.some formal source to consider:
Boeing 744 QRH: Procedures Beyond the Scope of the QRH

Introduction:

It is rare to encounter inflight events which are beyond the scope of
established non-normal procedures. These events can arise as a result of
unusual occurrences such as a mid-air collision, bomb explosion or other
major malfunction. In these situations the flight crew may be required to
accomplish multiple non-normal checklists, selected elements of several
different checklists (applied as necessary to fit the situation) or find little
or no specific guidance and need to rely on their own judgement and
experience. Because of the highly infrequent nature of these occurrences,
it is not practical or possible to create definitive flight crew procedures to
cover all events. (the bolding is mine)short thread just on the same subject can be found here http://www.pprune.org/tech-log/309286-flaps-n-gear-re-ba-777-ltr-post3852210.html

SFLY's problem was also discussed after D O Guerrero (http://www.pprune.org/members/169934-d-o-guerrero) asked http://www.pprune.org/rumours-news/309075-ba-b777-incident-heathrow-merged-post3845436.html?highlight=b777+%2Bstall#post3845436
how does landing at very low speed or at the stall speed increase the glide? I thought the maximum glide distance would be achieved at best glide speed which is presumably quite a lot greater than the stall speed on a 777? And therefore that any speed either greater or lesser would only have the effect of reducing the glide distance. I don't dispute that the crew would have wanted to slow the aircraft as much as possible just prior to touching down - but I would have thought that slowing to stall speed in order to try and make the perimeter would be an extraordinarily bad idea....and got the answers among others from
Mad (Flt) Scientist (http://www.pprune.org/members/58150-mad-flt-scientist):
You are correct that best glide speed is not stall speed, and an indefinite glide is best achieved at best glide speed.
However, gliding involves exchanging potential energy for kinetic energy (or, using a gravity component along the flight path to combat drag). If you were trying to extend a glide, and were, say, 500ft AGL, at say 1.3vs, you might be better off trying to use up some of the stored KE represented by the speed rather than simply use up that 500ft. Exactly what the best energy management would be is dependent on a lot of aircraft dependent factors, but hitting the ground at your lowest possible flying speed does ensure there was no wasted energy left which might have been used to extend the glide. eyeinthesky (http://www.pprune.org/members/27886-eyeinthesky):
Aircraft approach at a speed which gives them a margin above the stall speed (usually around 30% higher). In an emergency such as this, this 30% extra speed can be traded for height and therefore 'stretch' the flight path compared to that which would result from flying 30% above Vs with no power. It is a measure which has only a limited life, since once the stall speed is close the nose must be lowered again to prevent the stall. Then the aircraft is committed to where it will end up. It needs fine judgement and the failure to occur not before a certain point for it to work and the aircraft to reach the field. it would appear that in this case it worked, so well done to the teams aboard!

Unfortunately, there are too many crash sites in history where an attempt to 'stretch the glide' had insufficient energy (potential or kinetic) for it to work and the result was a wreck.and moosp (http://www.pprune.org/members/37975-moosp):
A colleague of mine flew several profiles on the 777-200 sim this morning (the real one, please, not the MS version) failing various engines at 500 and 300 ft on the LHR 27L model. A failure of 2 engines between 500 and 300 feet, with an attempt to stretch the glide towards stall speed produced a touchdown at a similar point on the visual model as the BA aircraft.

[CONF iture]

A colleague of mine flew several profiles on the 777-200 sim this morning (the real one, please, not the MS version) failing various engines at 500 and 300 ft on the LHR 27L model. A failure of 2 engines between 500 and 300 feet, with an attempt to stretch the glide towards stall speed produced a touchdown at a similar point on the visual model as the BA aircraft.

WojtekSz, the experiment related in the posted comment is biased for two reasons:

Attempting to stretch the glide won’t be obtained by bringing the speed towards stall speed, but by keeping the speed.
Both engines were not failed but still producing some minimal thrust above flight idle.

Once again, no judgement here on the BA38 crew actions, but I disagree with the main idea you push forward in the thread.

[misd-agin]

S.F.L.Y. - I'll say it again, you get it.

OK, for the sake of this argument let's presume that selecting Flaps 25 was the correct decision.

Who thinks slowing by from 118 kts Flaps 25 that they're INCREASING their gliding distance by slowing to 108 kts Flaps 25??? :ugh: You're going from (approx.) Vref -20 to Vref -30. That's going to INCREASE your performance???

So, if you're on the back side of the power curve(lift curve/drag curve, whatever you want to call it in pilot terms) and slowing an additional 10 kts will INCREASE your gliding performance?

Another issue is that by slowing to AOA limits there is no excess energy(ie airspeed) to try and flare. That woud allow for a slightly decreased sink rate at impact.

[cats_five]

i tried to compile my own answer to the problem presented by SFLY and when searching for B77 stall speed numbers i have found all the answers already there.
<snip>

Out of curiosity, what do you fly? I mean for real, not at your desk.

[WojtekSz]

cats_five:
unfortunately i fly nothing real, just the ms sim + good share of SLF
i am qualified mechanical engineer specializing in control systems, with open mind and deeper than average knowledge of physics (including fluid mechanics)

and in my free time i am carefully reading different threads on this forum ;)

FYI my answer was supposed to be based on energy conservation law + B777 data available from Interim Report + some other data available in the net. In short: lowering the nose earlier would result in landing earlier because it would increase ROD so in fact shorten time in the air (flying time).
I have learned my lesson studying the AF477 case so i thought that it would be more beneficial if i just remind what the others, more experienced pilots, have already said on the subject.

[WojtekSz]

CONF iture:
the experiment related in the posted comment is biased for two reasons:
Attempting to stretch the glide won’t be obtained by bringing the speed towards stall speed, but by keeping the speed.
Both engines were not failed but still producing some minimal thrust above flight idle.
well, do you really believe that the person who has flown the sim just pulled the stick to stall the plane? or maybe he was trying his best to fly as far as possible by trading the speed for distance?
i do not know if the engines were running idle (as you say) or just failed (as it is written) but IF they were producing ANY thrust this was adding energy to the system and this SHOULD enable flying further - yet the outcome and landing point was similar.
By the way, do you have any idea how many pilots have tried to replicate this landing? Have you heard about any of them getting better results?

... no judgement here on the BA38 crew actions, but I disagree with the main idea you push forward in the thread.
this IS judgement...

[WojtekSz]

misd-agin:
Who thinks slowing by from 118 kts Flaps 25 that they're INCREASING their gliding distance by slowing to 108 kts Flaps 25??? :ugh: You're going from (approx.) Vref -20 to Vref -30. That's going to INCREASE your performance???
So, if you're on the back side of the power curve(lift curve/drag curve, whatever you want to call it in pilot terms) and slowing an additional 10 kts will INCREASE your gliding performance? you mean from 118kts F30 down to 108kts F25 - do you happen to know what would be the speed if they would have stayed with F30? Suppose they would have stayed with AP on : would the speed be higher? Or maybe even lower as the control surfaces would have to be trimmed more to maintain the AoA the AP was trying to keep?


Another issue is that by slowing to AOA limits there is no excess energy(ie airspeed) to try and flare. That woud allow for a slightly decreased sink rate at impact. but there was a perfect flare! Actually it was LANDING rather then CRASH. Passengers have described it as 'rough' but still landing. See the experience of the reporters who were looking for sensational passengers crash stories - and failed ;)

[S.F.L.Y]

In short: lowering the nose earlier would result in landing earlier because it would increase ROD so in fact shorten time in the air (flying time).

In short: this is crap.

First of all nobody mentioned lowering the nose. Not raising it would already be enough to improve gliding performances.

You think that the longer you stay in the air the further you go and that's wrong. Gliding faster will bring you on the ground earlier, but the extra speed you have will take you further, even with a reduced flight time. That's what best glide speed is all about.

It works just the same on helicopters during an autorotation. To go further you need to dive.

[S.F.L.Y]

but there was a perfect flare! Actually it was LANDING rather then CRASH. Passengers have described it as 'rough' but still landing. See the experience of the reporters who were looking for sensational passengers crash stories - and failed http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/wink2.gif

You call a 1400 fpm impact a landing? Do I need to remind you that the landing gear went through the wings? A perfect landing is when you touch the ground at Vs with almost no Vz. In this case they had high Vz and were close to Vs, in other words no way to flare.

[wilyflier]

Wojteksz please leave the room

[CONF iture]

It was not sufficient to prevent the partial destruction of the aircraft. By any definition, that is a crash. (And happens to be a crash by the official definition, too.)
Actually I like the way they put it : "Aircraft damaged beyond economic repair"

WojtekSz, if you're ready to invest some money, go and hire a flight instructor in Warsaw who could demonstrate what it's all about. A Cessna will do just fine and pick up a windy day, result will be only more telling.

[misd-agin]

Tarq57 - "The only option the crew seemed to have was to reduce excessive drag (reducing flap a bit) and maintain an airspeed that would allow a controllable impact. "

-----------------------------------------------------------------------

Are you a professional pilot?

Aircraft have best glide speeds. Typically approach speeds are slightly slower than L/D to allow a slighter higher power setting. Slowing below best glide speed shortens your gliding distance(we'll skip the arguement about min sink with tailwind...).

"Reducing excess drag" - I've yet to see an official statement stating if total drag decreased or increased, and it's impact on gliding distance, by selecting Flaps 25 instead of leaving them at Flaps 30.

The flight was at Vref 135 kts with Flaps 30.
If slowed to 118 kts Flaps 30.
Flaps 25 were selected.
It slowed to 108 kts Flaps 25.
At 108 kts it couldn't slow anymore due to AOA protection from the FBW flight control system. So the sink rate increased. At that point everyone was along for the ride.

The arguement is 135 kts Flaps 30 gliding performance better than 118 kts Flaps 25? I don't know the answer for a fact. However, based on all my training, civilian, military, corporate, airline, to include heavy jet flying, fighters, and gliding, I'm inclined to believe Vref Flaps 30 is the correct choice. Unfortunately that is a scary view out the front windshield. I've done it in the simulator, which is a long way from real life, and it wasn't pleasent.

Every professional pilot knows that gliding performance was better at 118 kts Flaps 25 than it was at the AOA limit with 108 kts. Higher and higher AOA does not improve your gliding performance when you are slower than L/D.

The flight crew took one action that the aircraft would not have done by itself, that is the retraction of flaps 30 to flaps 25. Other than that there's a very good chance the aircraft would have hit in the exact same location if there were no pilots.

[S.F.L.Y]

The arguement is 135 kts Flaps 30 gliding performance better than 118 kts Flaps 25?

None of these two options happened. The flight ended at 102 kts flaps 25 (with headwind...) which is quite far from flaps 25 best glide speed corrected for the wind (probably more than 35 knots of difference). Since there was no time to accelerate to best glide speed, maintaining the speed at the moment flaps 25 were selected (118 kts) would still make a significant difference, especially on that side of the curve.

[cats_five]

cats_five:
unfortunately i fly nothing real, just the ms sim + good share of SLF
i am qualified mechanical engineer specializing in control systems, with open mind and deeper than average knowledge of physics (including fluid mechanics)
<snip>

It doesn't suprise me in the least you don't fly, it does suprise me that given your academic background you continue to peddle a load of twaddle. Did you actually read the Wikipedia links I provided?

Suggest you take up flying gliders - real ones. You will learn far more about flying doing that than you will here or on the simulator.

[Bis47]

Hello WojtekSz (and many others without real insight of "dead stick" landing)

Like many "High Academics", you apply mathematics to simplified models of the real world. That is, in essence, "theory".

Most flying theories about "best gliding" do not take into consideration transient effects :

- wind gradient close to the ground (500 ft and below)
- ground effect during the flare.
- "cushionning" effect of flaps (very little documented indeed)
- techniques for stretching the flare

Well trained pilots know better about that than highly educated university teachers ... Birds also, despite their small brain, know better ...

Had the so called flying pilot reduced flaps setting much earlyier, and had he kept the speed at a decent value, disregarding the religion about maintaining glide slope, the following would have happenned :

- initially, the aircraft would have lost somme altitude, descending below glide slope, aiming at a point short of the airport fence
- in this configuration, the aircraft would have flown at a better efficciency and lost less energy per mile travelled.
- reaching lower layers sooner, that is also meeting less head wind hence more efficiency again.
- when approching the ground or obstacles, it was then appropriate time to bleed airspeed and to "stretch the glide". This glide stretching is more spectacular in ground effect and low head wind than at 300 ft with full head wind and full induced drag.
- if the pilots had real good feeling, they should finally reset full flaps at the correct time just before impact.
- this "impact" whoud have happenned at minimum speed, but following a much improved angle of arrival and rate of descent. With some luck, the flare would have allowed a "no-accident" arrival, on the runway or shorthly before.

In any way, it was difficult to imagine a worse course of action than letting the speed going out of control, and reducing flaps when the aircraft was already very close to the stall. Ok, they finally avoided the stall, but the aircraft fell out of the sky, without any speed margin for a minimum flare.

_ _ _ _

In this very unusal situation, the captain did apply the normal procedure : let the copilot fly the aircraft, and try by himself to solve the problem. This was not a mistake. Many of us have done that, in the sim or in the real world. Unfortunately, the captain didn't succeed in restoring thrust, and the copilot forgot what "flying the aircraft" means - instead he just let the auto-pilot fly the ILS "as usual", until the last moment.

Not recognizing soon enough that an exceptionnal problem justifies throwing out all SOPs ... and applying instead basic airmanship, basic flying skills : this is what the storry is all about (regarding crew actions, and regarding company training as well).

Edit : "decent speed" instead of descent speed

[Bis47]

it was one of those days) you are struggling to maintain (even with today's autothrottle systems) plus or minus 5kts on the bugged speed (at best).


In that kind of weather, some margin about normal Vref should be applied, isn't it?

[M.Mouse]

..unfortunately i fly nothing real, just the ms sim + good share of SLF

And there was me reading this thread wondering how he could continually peddle the erroneous content in his posts when any pilot understands what rapidly happens to drag when increasing the AoA and on the back end of the drag curve and suddenly all becomes clear!

In that kind of weather, some margin about(sic) normal Vref should be applied, isn't it?

I can only speak for my airline and the B777 but with autothrottle engaged the answer to your question is no.

[Mr Optimistic]

non-pilot/non-sim

could anyone advise what the response of the a/c would have been had the blockage(s) suddenly cleared ? Would power start to increase to the freed engine(s) ?

[M.Mouse]

Yes. However from idle or thereabouts the acceleration response is sluggish until the engine reaches a certain speed where acceleration is more or less instant.

It is one of the reasons immediately prior to take off that you will notice an aircraft's engines accelerated from idle to a low power setting followed by a brief pause for the engines to stabilise before the required take off power is applied.

[exeng]

In that kind of weather, some margin about normal Vref should be applied, isn't it?

Not so in all 737 models 200 to 900, 757, 767 and 777 according to Boeing SOP's when the A/T is engaged. The A320/319 (and other buses I believe) use a feature called 'ground speed mini' which could be quite startling in very strong winds!


Regards
Exeng

[S.F.L.Y]

In any way, it was difficult to imagine a worse course of action than letting the speed going out of control, and reducing flaps when the aircraft was already very close to the stall. Ok, they finally avoided the stall, but the aircraft fell out of the sky, without any speed margin for a minimum flare.

At least someone who understand and who has practical experience of what we are talking about!

Woodpickle, I'm not rated on the 777 but handled 16,000 ft of engine out glide in IMC with in a fully iced aircraft. Do I qualify to post in this thread?

Eleven years of military flying on both fixed wing and rotary machines gave me the opportunity to perform 1h sessions every three months of dead stick landings or autorotations in various configurations.The procedure described by Bis47 is exactly what is supposed to be done and what actually works best. I don't think this experience comes within the 777 TR package...

[FullWings]

Bis47,

I think the majority of what you're saying is accurate, even essential reading for when you end up in a forced undershoot situation. However, I do think it unrealistic to expect many airline pilots to have encountered/practiced this scenario - why should they? Most of us have only flown powered aircraft and there is very little, if any, formal training on how to counter a developing undershoot in the way you suggest (correct, IMHO). It's mostly "bar talk". The emphasis is on getting the approach right in the first place.

Not recognizing soon enough that an exceptional problem justifies throwing out all SOPs ... and applying instead basic airmanship, basic flying skills : this is what the story is all about (regarding crew actions, and regarding company training as well).

Again, I agree with the sentiment but the reality is that in the last minute of an (uneventful) 12hr flight, it takes even the Yeagers of this world a short time to work out just what the **** is going on. Remember, the engines were still running and there were no warnings, messages or alerts.

Regarding training, we practice approaches with all engines operating, one out and none at all, not with both stuck on random thrust. I don't see how that could be done any differently as scenarios such as the BA38 are so sensitive to weights, timings, wind, etc. that there is little to take away to apply to a generic class of failure. Also, bear in mind a) the statistical rarity of such events, leading to poor training 'value' and b) the understandable reluctance to run a simulator exercise where a crash is a likely outcome. With limited time and money, most companies concentrate on things that are breaking aircraft regularly, like 'rushed' approaches, CFIT, etc.

If the failure had occurred a minute earlier, they'd have probably been at F20 and Vref20 + a bit. The power settings the engines froze at were just enough to allow a stable approach in that configuration, even an autoland. Hey, if they'd closed the TLs instead of firewalling them, they'd have got the thrust back shortly afterwards as the ice melted on the FOHE faces... but no-one knew that at the time.

[Smilin_Ed]

Remember, the engines were still running and there were no warnings, messages or alerts.
Does anyone know what the fuel flow was? Although they probably wouldn't have thought to look at the fuel flow, that would have given them a clue. This, of course is hindsight. I assume that is recorded of the flight recorder.

[CONF iture]

The A320/319 (and other buses I believe) use a feature called 'ground speed mini' which could be quite startling in very strong winds!
That GS mini feature could have well provided a nice 20 extra knots when most needed.
Would be really curious to simulate and analyse a similar scenario in a 340 …


Report says FF were at 5 and 6000 pph ...

[WojtekSz]

bis47: the transient effect are really very interesting, still i will always prefer to fly higher and slower than faster and lower ...

especially over traffic on A30 ;)

Gentelmen, thank you for most interesting time, pls excuse me if you feel that it was a shade ;) too much speculative

[FullWings]

Does anyone know what the fuel flow was? Although they probably wouldn't have thought to look at the fuel flow, that would have given them a clue. This, of course is hindsight. I assume that is recorded of the flight recorder.
Fuel flow is not one of the primary engine indications (EPR, N1 & EGT are). At that point on the approach, the handling pilot would have had his hand resting on the thrust levers and would have felt the autothrottle moving them to increase power, due to a shortfall in airspeed, which would have also been noticed on the PFD. All normal so far. What was abnormal was the lack of engine response to this movement; not long afterwards this was picked up by the crew and at that point fuel flows became irrelevant.

The differences between the power setting required for the approach and the ones the engines 'hung' at weren't huge. From what I remember it was 1.02 & 1.03EPR with 1.03-1.04EPR/48%N1 needed for F25 and c. 1.06EPR/55%N1 for F30.

[M.Mouse]

..still i will always prefer to fly higher and slower than faster and lower ...

Clearly you have not listened or understood what qualified pilots have been repeating ad nauseum. Your continual misinformed posts are an irritation to anybody with a basic understanding of lift/drag ratios.

[CONF iture]

It takes us back to the eternal 'Habsheim' argument as to whether an 'iron' a/c such as 737 would have had enough energy to just clear the trees without stalling unlike the AB with its alpha-floor protection which limited its climb = no trees, no crash.
BOAC, as you bring the subject of Habsheim, the idea that the airplane was limited to prevent it from stalling is part of the myth that’s not even supported by the figures published in the official report.

ALPHA MAX, which is an AoA, was never reached, still 3 degrees off. Therefore the 320 was not limited to prevent it from stalling.
But what we might logically suspect is : Its body attitude may have been limited by an unpublicized protection which would limit the body angle below a specified altitude that could be anywhere below 100 feet RA. Such a protection related to the airplane attitude, could have been designed to merely prevent tailstrike occurrences …

[lomapaseo]

CONF iture

But what we might logically suspect is : Its body attitude may have been limited by an unpublicized protection which would limit the body angle below a specified altitude that could be anywhere below 100 feet RA. Such a protection related to the airplane attitude, could have been designed to merely prevent tailstrike occurrences …

Now that is a surprise if confirmed

[bearfoil]

A surprise, perhaps. But why? Tailstrikes can be hideously expensive and dangerous; what would be inconsistent with AB philosophy to protect the a/c from the pilots?

Besides, trees don't grow on runways; what was the a/c doing there in the first place.

MFP. Max flare prot.? MWP Max Whatever Prot? In places this a/c doesn't belong, does it need protection? Or a DM switch. 'Defeat Max __'.

bear

[BOAC]

Interesting, CONF - can you expand further? Incidentally, I did not suggest that the AB was being prevented from 'stalling', just that A-prot may have been active. Different thing altogether. Does a-prot limit at a-max - or 3 degrees below............?

Also I would have thought that at 100RA you could practically stand the ***** vertically and not 'strike'?

Anyone else know of this 'unpublicized protection'? TyroP?

[DozyWannabe]

AFAIK there was no alpha floor protection under 100ft RA and the only thing the computers had to do with the crash was keeping the wings level as it hit the trees.

Though what this has to do with an undershoot on approach accident like BA038 other than a kneejerk "The machines will kill us all!" response is beyond me... ;)

[bearfoil]

I see striking similarities. Unavailable (or late) power, Too high AoA, not high enough, Replace the turf with trees, and two a/c hit the deck too early, with a combination of errors both crew and equipment related. One mishap is very strongly crew related, the other equipment derived.

All right, call it stark contrasts, then.

bear

[phil gollin]

So, the second anniversary, and apart from a lot of very grateful passengers has anything been decided ?

Any ideas on progress on the scientific tests, or another interim report ?

.

[S.F.L.Y]

Sometimes investigators and manufacturers do not show much enthusiasm in sorting out accidents, just like for the A320 lost in Perpignan a year ago... At least for the BA038 BA managed to give safety medals in a couple of days and showed the airline was above all others (even before knowing what really happened :}).

[M.Mouse]

Please try and show restraint from the modern trend of wanting everything immediately.

The AAIB have never, in my observations, delayed or supressed a report. What I do see when they publish a report is one that is clear, unambiguous in what it says and sticks rigidly to the facts, making recommendations as it sees fit.

It is my understanding that all BA RR powered B777s now have modified fuel/oil heat exchangers fitted and so the apparent dangers appear to have been dealt with according to the known facts so far.

What is the problem apart from impatience on your part?

[phil gollin]

I agree with your sentiment, however;

"...... It is my understanding that all BA RR powered B777s now have modified fuel/oil heat exchangers fitted and so the apparent dangers appear to have been dealt with according to the known facts so far. ...."

There have been NO findings which deal with the "known facts", merely unrepresentative tests which indicate possible problems, for which the fuel/air heat exchanger mods should be o.k..

[RomeoTangoFoxtrotMike]

Sometimes investigators and manufacturers do not show much enthusiasm in sorting out accidents, just like for the A320 lost in Perpignan a year ago...

If SLFY could actually have bothered to read the thread, he'd have spotted posts 851 (http://www.pprune.org/4043766-post851.html)and 1005 (http://www.pprune.org/4090353-post1005.html) et seq[1].... :ugh: :rolleyes:

/RTFM

[1]
16th July 2008, 22:55 http://www.pprune.org/4269403-post1534.html
2nd September 2008, 16:53 http://www.pprune.org/4368543-post1692.html

[S.F.L.Y]

Thanks for the acronym but if you had read the thread carefully you should already have diagnosed your dyslexia...

I think we know how long it usually takes to get a report while most of the time much more data is released during the early stages (in compliance with annex 13). Just like for the Perpignan's A320 it didn't take long for the operator/manufacturer to release it's own conclusions while the investigations seems to be uncertain...

[p51guy]

I don't see anything this crew could have done with the power they had available to make the runway. They did a fine job and it worked out pretty well. They might have exceeded AOA but only to not land any shorter than they did. Pilots did a great job with what they had. Hats off to them. Sully into the Hudson is another example of good airmanship. Doesn't mean we couldn't do it but we never had to, thank God.

[bearfoil]

IMO it cannot be seen any other way. Phil Gollin, the fuel 'mystery' lives, I don't think the FOHE 'fix' solved the 'problem'.

[misd-agin]

L/D is L/D. "Exceeding AOA" (?) does not increase your gliding distance.

[bubbers44]

If established at best L/D when they took manual control I agree but the autopilot from what I remember was holding the glide slope so they were well under L/D and a few hundred feet off the ground they would have had to lower the nose and greatly increase their sink rate to regain it. In Sully's case he had the altitude from 3,000 feet to do that. In this case the engine problems happened at 700 ft so they had to be well below 500 ft before they disconnected the AP. I'm sure when this happened is well documented in a few thousand posts back.

[S.F.L.Y]

Nobody said they should have lowered the nose and reduced the AoA once identified the loss of thrust. Stopping increasing it would already have been great, flying at 118 kts is still better than stalling at 102... (and definitely takes you further).

[M.Mouse]

Phil Gollin, the fuel 'mystery' lives, I don't think the FOHE 'fix' solved the 'problem'.

Fascinating stuff. Great that you have access to the final report which explains your statement.

It would be useful to know when the rest of us will be able to read it as well.

[phil gollin]

The heater exchange mods are only valid for a set of unrepresentative tests.

The tests themselves raised supposedly previously unknown behaviour of fuel/water mixtures (?????).

SO;

1: They still need to carry out representative tests (of whatever sort) which cause the engine problems or otherwise explain the engine failures by suggesting different fuel conditions from those extrapolated from the evidence.

2: IF there is this previously unknown behaviour of fuel/water mixtures then ALL - REPEAT ALL - certification authorities and ALL - REPEAT ALL - airframe/engine combinations need to be re-checked to see if they are immune from these effects.

Strangely enough it is the second of the above that I have more problems with. I await the final (or third interim) report with interest.

[tanimbar]

Warning: I'm non-professional; not crew, not engineer - just scientist guest and thanks.

In support of Phil Gollin's comments ....

The critical issue arising from the crash of BA038 is starkly worded below (from the AAIB interim report (Water ice in fuel, p12)),

Below this temperature (-18C) little is known about the properties of ice crystals in fuel and further research may be required to enable the aviation industry to more fully understand this behaviour.Either the AAIB made a mistake in this claim or the industry has an immense problem. Either way the AAIB's final report will be very interesting.

Regards, Tanimbar

[Landroger]

I feel obliged to make the same disclaimers as Tanimbar, although for scientist read engineer - non aero. Nevertheless, I have followed this thread since the day the accident happened, indeed it was the real reason I joined this forum. Mainly because of the almost unheard of bilateral engine 'failure', which from an engineer's point of view is the equivalent of a good 'whodunnit' - better by miles than the Davinci Code. Yes, I know the engines didn't actually fail; failed to respond is a better phrase, but that doesn't get round the fact that both of them did it at the same time.

I have read as much of the linked information about ice carried in fuel and the tests carried out as I could. I have read every linked pronouncement from the AAIB and I have, as I said, read every post in this thread, looking for the little nugget that stops my engineering alarm bells ringing. And the oil heat exchanger on RR Trent option aeroplanes didn't do it for me. I tend to agree with Phil Gollin and Tanimbar, that the case for the heat exchanger is, at best, unproven.

On the other hand, one could - as I often do in my day job - apply the principle of Occam's Razor and say that since this is the simplest explanation, we should not strive too officiously to find another. However, the heat exchanger issue appears to have been addressed and there is very, very little other forensic evidence either way, what if it is not the culprit ..................

Roger.

[bearfoil]

This topic is well covered here. Simply put, The 'fix' piggybacks a thermodynamic demand on the FOHE to melt ice accumulation. This is not a function of the original design, and mods to the OE unit don't resolve questions that have been asked early and often in this thread by fuel engineers, pilots, and others. Period.

The rest is politics, wishin' and hopin'.

bear

[lomapaseo]

Either the AAIB made a mistake in this claim or the industry has an immense problem. Either way the AAIB's final report will be very interesting.

Regards, Tanimbar


Unknowns are just that. They do not necessarily signify an immense problem.

They are expected to be accounted for as part of the underlying risk in our lives for anything that we design. It's the knowns that we apply processes to address.

I don't expect the AAIB to solve the problem, but leave it to the industry (manufacturers and regulators) to reduce the degree of the unknowns in this regard.

[CONF iture]

Blocked FOHE, blocked PITOT ...
Ice crystals : last threat in the sky ?

[Hydroman400]

I don’t fully agree with your statement regarding the intention of the original design. The FOHE is used to heat the fuel for ice protection. The FOHE forms part of the engine Thermal or Heat Management system, which to quote the Rolls Royce engine book “[I]A responsibility of the heat management system is to ensure that the fuel temperature is above 0 deg C at the critical and vulnerable parts of the fuel system for the majority of operating conditions. The heat rejected by the engine oil system via the FOHE is normally sufficient to ensure fuel temperature above 0 Deg C, so protection the fuel system from fuel-borne ice.”

I recall that Boeing has made it’s own investigation on the issue (white paper) and seem to believe that the reason that the other B777 engine (PW) has not suffered similar events is due to the engine fuel system architecture; warm spill flow from the FMU is re-introduced upstream of the FOHE and therefore warms the colder fuel coming from the aircraft fuel tanks, before it contacts the face of the FOHE.

It must be noted that the RR Trent 800 does not re-introduce warm spill flow upstream.

I wonder if a further modification for future RR engines will change this philosophy instead of removing tapered ends of the FOHE tubes…….

[bearfoil]

Hydroman400

To me, the way fuel ice is addressed via FOHE is backwards, and under conditions that were 'tested' by Boeing, show the concept lacking. Now the inability to 'de-ice' ice laden fuel is patent, per the reports and the extensive work done by the manufacturer, though it too is not dependable. Delta rolled back at 35k feet and lost 5k to regain thrust. At those frigid temps. the FOHE is shut down, and the oil is 'cooled' by air cooler. At take off under high demand, the oil heats rapidly, and the fuel cools the oil. Let down or cruise are the problem, under these conditions, the Exchanger is inop. In other words, even a spill valve would be putting frigid fuel back to the face. The engine operation for the Trent does not mention "fuel de-icing", not in the a/c manual.

You have a most valid point, though I disagree with the ability of the unit to perform to RR's expectations, via its manual. A long discussion, but what we have here is an enhanced demand due to a surprise in fuel performance. This new demand is addressed by trimming tubes back to face sheet, instead of re-engineering a new unit (architecture); although a 'new' FOHE wouldn't necessarily be expected to mitigate the problem well, if at all, given that the fuel performance is still "mysterious".

bear

[Hydroman400]

When I mentioned spill flow, I was referring to the 'excess' flow from the HP gear pump, which due to compression and pressure drop across the regulating valve imparts an increase in the fuel temperature regardless of whether the fuel is acting as a heat sink for the FOHE. As the gear pumps provide flow proportional to the gearbox and hence NH speed, the available flow is always more than the required flow to maintain selected N1, EPR etc. This warm excess flow is then re-introduced upstream of the LP pump (impeller). What seems to be important is where it is re-introduced

I am in no way saying that the RR FOHE re-design will completely address the problem, as for now the complexities of the issue are not fully understood.

[bearfoil]

Hydroman

I have the schematics for both the Trent and GE somewhere in my computer, and I acknowledge your comment re: Boeing's note that RR has no upstream inflow of discharge from the Spill Valve. Another poster suggested that beyond the added heat issue of HP passage, the gears would additionally masticate any solid Ice in fuel that had passed through the tube matrix of the HE.

The salient question becomes, If this process ('Spill', 'Mixing') mitigates Fuel Ice in any way and remains unaddressed relative to upgrading the Trent, well, is the AD a "Palliative", mechanically and politically? Airfoilmod was on about re-engineering the architecture as well as the FOHE, and SmilinEd suggested Fuel Heat, a process Boeing has utilized in a/c that fly to 60k feet routinely. Severing the protruding tubes at the face sheet amounts to a "Subtraction", indicating that nothing new has been added to this system, and no substantial change has occurred.

In addition I would add that removing the extra length of the tubes eliminates an (inadvertent?) nesting area for some amount of ice accumulation of the type identified by Boeing as "Migratory". In this sense, I would suggest that the FOHE performance has been actually degraded relative to Fuel Icing caused rollback.

bear

[G-CPTN]

Beeb announcing that a report just issued gives the cause of the undershoot to be ice in the fuel . . .

BBC News - Heathrow BA plane crash caused by 'unknown' ice fault (http://news.bbc.co.uk/1/hi/england/london/8504734.stm)

[PoloJamie]

Formal report is on the AAIB's website, although the actual report's link is broken atm
Air Accidents Investigation: 1/2010 G-YMMM (http://www.aaib.gov.uk/sites/aaib/publications/formal_reports/1_2010_g_ymmm.cfm)

[dxzh]

Try the following links:

http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Synopsis.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Contents.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Section%201.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Section%202.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Section%203.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Section%204.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Appendices.pdf
http://www.aaib.gov.uk/cms_resources.cfm?file=/1-2010%20G-YMMM%20Glossary.pdf

[The_Steed]

'Ice problem' in BA jet accident - MSN News - MSN UK (http://news.uk.msn.com/uk/articles.aspx?cp-documentid=152078179)

A breath of fresh air to have a report that is factual, concise and not full of exaggerations... :ok:

[302B31]

Link now fixed

[phil gollin]

I'm amazed.

I'll do my reply in a couple (or more) posts, the first a summary and the other(s) some extracts.

I have ploughed my way through the report and am extremely unimpressed.

I find the report extremely annoying.

The main reason is that whilst the FOHE (Fuel Oil Heat Exchanger) may be the main reason for the engine roll backs the report is amazing in the way it treats the causes (and testing).

It is amazingly obvious that they did/do not want to mention the actual water content of the fuel on the flight. It SEEMS to be mention only three times and almosy only in passing at "35 - 40" ppm, HOWEVER, all the tests were run with concentrations of 90 ppm (or more). There is no examination in detail of the actual measured water levels or what the actual state of the fuel/water mixture might have been like at the landing stage.

Also, the tests (at UNREPRESENTATIVE water content levels) were inconsistent and it would seem were never tried at more representative water content levels.

So, what did the tests show ???????

I don't know. It would seem that somehow unrepresentative tests are relevent and that the whole report should ignore the actual fuel/water conditions.

And as for the lack of future actions regarding the previously unknown phenomenum of the fuel/water slush with ALL other airframe/engine combinations that is just running away from a huge cost.

I am extremely disappointed.

[phil gollin]

(PART ONE of TWO)


One needs to read the whole report, however some highlights that I THINK relevant ;


AA:- From “Synopsis” ;

“2) Ice had formed within the fuel system, from water thatoccurred naturallyin the fuel, whilst the aircraft operated with low fuel flows over a long period ……..”

What does “naturally” mean ?


BB:- From “Synopsis” ;

“3)The FOHE, although compliant with the applicable certification requirements, was shown to be susceptible to restriction when presented with soft ice in a high concentration, with a fuel temperature that is below ‑10ｰC and a fuel flow above flight idle.”

Why just the “FOHE” here when they talk of the “fuel system” elsewhere ?


CC:- From “Synopsis” ;

“4) Certification requirements, with which the aircraft and engine fuel systems had to comply,did not take account of this phenomenon as the risk was unrecognised at that time.”

And how have thing changed now for ALL aircraft and engine combinations ?


DD:- From 1.11.2 ;

“….. As the DFDR record commenced, an active status message was recorded from the FQIS water detector located in the centre fuel tank (Figure 15). The status message remained active for five consecutive samples of that parameter: a total of five minutes and twenty seconds. After the pushback, the park brake was applied and the aircraft remained stationary for about three and a half minutes before taxiing. As the aircraft taxied, the levels of aircraft vibration increased. The water detector message remained active for a further 100 to 160 seconds before extinguishing; the exact time could not be confirmed due to the long period between successive samples of the parameter. There were no further indications from the centre tank water detector. There were no indications from the left and right fuel tank water detectors during the flight. ……..”


EE:- From 1.11.2;

“……Approach

As the flaps reached the 30° position the airspeed had reduced to the target approach speed of 135 kt and the autothrottle commanded additional thrust to stabilise the airspeed (Figure 20, Point A). In response to variations in the wind velocity and associated airspeed changes, there followed a series of four, almost cyclic, thrust commands by the autothrottle (Figure 20, Point B). It was during the fourth acceleration, and as additional thrust was being commanded, that the right engine, followed some seven seconds later by the left engine, experienced a reduction in fuel flow (Figure 20, Point C). The right engine fuel flow reduction occurred at a height of about 720 ft and the left engine at about 620 ft. Just prior to the reduction in right engine fuel flow, about 2.5 nm from the runway, the flight crew were visual with the runway and the co-pilot became pilot flying (Figure 21).

Of the four thrust commands it was the second that resulted in the highest delivery of fuel flow, reaching a peak of 12,288 pph for the left engine and 12,032 pph for the right (Figure 20, Point D). These peaks occurred about 26 seconds prior to the reduction in fuel flow to the right engine. Peak fuel flows during the first and third thrust commands were lower, at about 9,500 pph and 9,000 pph respectively.

During the fourth thrust increase, the right engine fuel flow had increased to 8,300 pph before gradually reducing. The recorded EPR then started to diverge from the commanded EPR and the right engine FMV opened fully (Figure 20, Point E). Some seven seconds later, the left engine fuel flow, which had increased to 11,056 pph, also started to reduce and the left engine FMV also moved to its fully open position (Figure 20, Point F). The QAR record ended shortly after. ……..”


FF:- From 1.12.4.2 ;

“……..Water Scavenge systems

The nozzles from all the water scavenge jet pumps were removed and examined on 2 February 2008 and the following discrepancies were noted.
When the nozzle from the right main scavenge jet pump was removed from its housing half a teaspoon of a ‘jelly‑like’ substance, later identified in a laboratory as “water”, was found in the housing. It is not known if this water was originally lodged in the nozzle and was pulled through the flap valve into the housing, or whether the water had been introduced into the housing during a previous maintenance activity. The water was tested for microbiological contamination and the quantity of contamination was assessed as negligible. ……..”


GG:- From 1.16.2.1 ;

“1.16.2.1 Fuel samples

Following the accident, 66 fuel samples were taken from the aircraft, and engines, and a number of these samples were tested by QinetiQ and another independent laboratory. ………………………………………………..”

…………………An explanation of the testing conducted on these samples and the results are detailed in Appendix C.

The fuel samples from G‑YMMM complied fully with the specifications for Jet A-1. The sampled fuel had a fuel freeze temperature of -57°C and water content of between 35 and 40 parts per million (ppm). …………”


HH:- From 1.16.2.2 ;

“…………….. It was reported in the AAIB Interim Report, dated 4 September 2008, that 71,401 kg of No 3 Jet Fuel (People’s Republic of China) had been loaded onto G‑YMMM at Beijing prior to the start of the accident flight. Since receiving this initial information the AAIB was provided with further documentation indicating that the fuel was Jet A-1, which had originated in South Korea and was shipped to Tianjin, China, before being transferred to the airport bulk fuel storage facility at Beijing.

The investigation was provided with a number of documents including the refinery test certificates, airport storage tank records, hydrant records and refuelling vehicle records. The Korean test certificate indicated that the fuel was compliant with Check List Issue 22, which ensures that the fuel meets the requirements of Defence Standard 91-91 and ASTM D1655. Quality assurance checks undertaken at various points on its journey to the aircraft showed no evidence of significant contamination of the fuel. Moreover, the properties of the fuel recorded in the refuelling receipt and quality assurance certificates were consistent with the test results for the fuel samples taken from G‑YMMM after the accident. ………..”


N.B. I would note that both here, and earlier in the Synopsis, opportunities for mentioning water levels and/or explaing likely water levels in the actual flight fuel are not taken.



II:- From 1.16.5.4. ;

A large section which again generally carefully avoids comments re. actual/perceived flight fuel water content, except for ;

“….. The repeatability of the test was such that with a water concentration of 100 ppm there was a 95% chance that the test would show a result between 76 and 124 ppm. ……”

“………. A target water concentration of 90 ppm (as defined in ARP 1401) was selected for all the tests. ……”

“………… using fuel conditioned with approximately 90 ppm of water and maintained at a temperature of -20°C, which was near the fuel temperature at which the rollbacks occurred on G‑YMMM and N862DA (refer to 1.18.2.1). ……..”

(But not the water level of the flight fuel)

“………… The only occasion when it appeared that there might be a sufficient quantity of ice to block a pipe occurred when approx 6 litres of water had been injected into the boost pump inlet over a period of 7 hours. During this period the flow rate was maintained at 6,000 pph and the water content varied between 100 and 150 ppm. ………”

“…….. -As little as 25 ml of water, when introduced into the fuel at an extremely high concentration17, can form sufficient ice to restrict the fuel flow through the FOHE.

17 The water concentrations in the fuel, when the water was introduced in the manner used in these tests, were of the order of 100 times the concentration levels specified in the certification requirements. …………”


JJ:- From 1.16.5.4

“………….Refuelling at Beijing

A test was run to simulate refuelling the aircraft at Beijing when fuel at a temperature of 5°C was added to fuel tanks containing fuel at a temperature of -20°C.

During the test a fresh batch of fuel at 10°C was added to fuel at a temperature of -22°C in the environmental tank at a ratio of 1/1. The boost pump was run for 25 minutes to provide pump cooling and motive flow for the water scavenge pump. Whilst a few ice crystals were observed floating in the fuel, there was no build up of ice either in the tank or on the boost pump inlet screen or inlet pipe. …….”

Note :- no mention of water levels


KK:- 1.16.5.4 ;

“…….. Water concentration

During the environmental tests the amount of water sprayed into the fuel was closely monitored to try and maintain the concentration at 90 ppm. Frequent fuel samples were taken throughout the tests and the water concentration was established by running at least two Karl Fischer tests on each sample. The results indicated that the water concentration in the fuel flowing through the test section of the rig varied between 45 to 150 ppm. The discrepancy between the metered and measured water content might be explained by ice collecting, and being released from the supply tank and the pipes being tested. However, it was also observed, from the results of several Karl Fischer tests carried out on the same sample of fuel, that the measured water concentration varied by up to 60 ppm. ……….”

(But as mentioned in “II” above the “repeatability” of these tests is questionable.)


LL:- 1.16.6 ;

“…… 1.16.6 Ice formation in B777 fuel tanks

Following the defueling and draining of G‑YMMM’s main fuel tanks, some fluid remained trapped between the stringers adjacent to Rib 8. Approximately 0.6 litre of fluid was removed, by syringe, from each main fuel tank and stored in a clean glass jar. The fluid settled into two distinct layers and was analysed by QinetiQ who confirmed that the 0.6 litre sample from the left wing included 0.2 to 0.25 litre of water and the sample from the right wing 0.1 litre of water.

To establish if the quantities of free water found in the dead space in the fuel tanks on G‑YMMM were normal, two of the operator’s other Boeing 777s were inspected after arriving from Beijing on 21 February 2008 and 17 March 2008. Access was gained to the main fuel tanks within 3 hours of the aircraft landing and while the fuel temperature was still below 0°C. On both occasions small amounts of ice were found adjacent to Rib 8, around the edge of the stringers in front of the forward boost pump inlet. The largest piece of ice, on both aircraft, had built up around the inboard of the tank hatch and measured approximately 14 cm x 11 cm x 3.5 cm. This ice was firmly attached to the bottom of the fuel tank. There was no evidence of ice or slush in the rear part of the tank; however there were small pockets of water in a number of locations along Rib 8. It is estimated that the total amount of ice and water was about 0.5 litres. From the distribution of the ice and water, it would appear that water collects and ice forms mainly forward of the front boost pump inlet where there are no water drain holes in the stringers. ……………….


MM:- From 1.18.1.2 to 1.18.1.4 ;

1.18.1.2 Water in aviation turbine fuel

Water is always present, to some extent, in aircraft fuel systems and may be introduced during refuelling or by condensation from moist air which has entered the fuel tanks through the tank vent system. The latter effect is greatest when a cold soaked aircraft descends into a warm moist air mass. The water in the fuel can take one of three forms: dissolved, entrained (suspended) or free water.

Dissolved water: Dissolved water occurs when a molecule of water attaches itself to a hydrocarbon molecule; the amount of water dissolved in fuel is a function of humidity, temperature and the chemical constitution of the fuel. As a general guide the dissolved water content of aviation turbine fuel in parts per million (ppm) is approximately numerically equal to the temperature of the fuel in degrees Fahrenheit. When warm fuel is cooled the dissolved water is released and takes the form of either entrained or free water.

Entrained (suspended) water: Entrained water is water that is suspended in the fuel as tiny droplets and may not be visible to the naked eye in concentrations below 30 ppm. At higher concentrations entrained water will give the fuel a cloudy or hazy appearance, depending upon the size and number of water droplets. Entrained water can be formed by the release of dissolved water as the fuel cools, by violently agitating water and fuel together, or if there is a surfactant in the fuel.

A surfactant acts to stabilise small water droplets so that they do not form large water droplets that would settle out on the bottom of the tank. The maximum amount of surfactant allowed in aviation turbine fuel is not directly specified in the fuel specification but is controlled by water separation testing as part of fuel delivery requirements.

Agitation can occur during refuelling, mixing of the water scavenge outlet with the bulk fuel, or as the fuel and water pass through the aircraft fuel pumps. Entrained water will settle out of the fuel, but the rate is dependent on the droplet size, the density of the fuel and theamount of fuel agitation. As a general rule, under static conditions, entrained water is considered to settle at a rate of about one foot per hour; however it is unlikely that on an in-service aircraft all the entrained water would have the opportunity to settle out of the fuel.

Free water: Free water is the water which is neither dissolved nor entrained and, as it has a higher density than the fuel, it takes the form of droplets, or puddles of water lying on the bottom of the fuel tanks. Free water can also be found in the fuel filters and stagnation points within the fuel delivery system.


1.18.1.3 Estimated water content of fuel on G‑YMMM

Based on the temperature of the fuel, it was estimated that the fuel loaded at Beijing would have contained up to 3 litre (40 ppm) of dissolved water and a maximum of 2 litre (30 ppm) of undissolved water (entrained or free). In addition, it was estimated that a maximum of 0.14 litre of water could have been drawn in through the fuel tank vent system during the flight to Heathrow. This water would have been evenly spread throughout the fuel and would have been in addition to any water remaining in the fuel system from previous flights. These quantities of water are considered normal for aviation turbine fuel.


1.18.1.4 Formation of ice in fuel

As water cools it freezes and forms ice as follows:

Dissolved water: Any water that is still dissolved in the fuel at low temperatures will not form ice because the water molecules are still chemically bonded to the fuel. Dust particles in the fuel could provide a nucleation point for the formation of water droplets that could then form ice. However, at low fuel temperatures the concentration of dissolved water is very low and therefore the amount of ice formed by this mechanism would be small.

Free water: Free water forms ice as it is cooled below its freezing point and within the aircraft fuel tanks the cooling mechanism is the effect of the TAT on the lower wing skin; it is the water closest to the wing skin which freezes first. From the examination of two other B777 aircraft, by the AAIB, it appeared that, in the main fuel tanks, ice forms around the rivets, access panels and structure adjacent to Rib 8 and it was very difficult to release some of this ice from the bottom of the tank. For the ice to release it is necessary to increasethe temperature of either the fuel or the lower wing skin above the melting point of the ice.

At the point, in the accident flight, when the engines did not respond to the demand for an increase in power, the fuel temperature was -22°C and the TAT was 12°C. Photographs of G‑YMMM taken as it crossed the airfield perimeter show the inboard sections of the lower wings skins, which form the main fuel tanks, covered in frost which indicates that the wing skin was very cold; therefore, there was no release mechanism for any ice that may have formed on the bottom of the fuel tank.

Entrained (suspended) water: Entrained water in fuel will freeze and form ice crystals, which turn the fuel cloudy. Because the density of the ice crystals is approximately the same as the fuel, the crystals will generally stay in suspension and drift within the fuel until they make contact with a cold surface. Due to impurities in the water the ice crystals will not start to form in the fuel until the temperature has reduced to around -1°C to -3°C. As the temperature is further reduced it reaches the ‘Critical Icing Temperature’ which is considered to occur between -9°C and -11°C. The ‘Critical Icing Temperature’, is the temperature at which the ice crystals start to stick to their surroundings. As the temperature is further reduced to -18°C, the ice crystals start to adhere to each other so that they become larger, with the risk of blocking small orifices.

The temperature range over which ice crystals in fuel adhere to surfaces, and each other, is sometimes called the ‘sticky range’. From observations made during the sub-scale testing, the investigation defined the ‘sticky range’ as being between -5°C and ‑20°C. …….”


(TO BE CONTINUED >>>>>>)

[phil gollin]

(PART TWO of TWO)



NN:- From 1.18.1.5 ;

“………. During this investigation very hard, dense ice was found in the bottom of the aircraft main fuel tanks and occasionally, during the testing, a thin layer of what appeared to be rime ice formed around the outlet of the boost pump check valve housings. However, for the most part, during the icing tests, the ice which formed within the fuel system pipes was very soft and could be easily moved around. Temperature variations did not appear to affect the type of ice that was formed. When the ice was melted it was found to contain a mixture of fuel and water.

To overcome the difficulties in maintaining the water concentration in cold fuel, the aircraft manufacturer fitted an acrylic box around the boost pump inlet and introduced a mixture of warm fuel and water into the cold fuel, through an atomising nozzle. Nitrogen was then blown across the nozzle to prevent the water freezing and blocking the holes. This produced ice crystals which had formed from a high concentration of entrained water, which would then adhere to the inside of the pipes. During the accident flight, the ice crystals would have formed from a lower concentration of entrained water. Some of this entrained water would already be present in the fuel and some would have formed as dissolved water was released as the fuel cooled. ………….”


OO:- From 2.5 ;

“……….. Water will always be present in aviation turbine fuel. At 35 to 40 ppm the total water content measured in the fuel samples taken from G‑YMMM was similar to that in the samples taken from another B777, G‑YMMN. The small quantity of water droplets found in the engine fuel filter housings was also similar. The quantity of free water found in the main fuel tanks on G‑YMMM, after the accident, was also similar to the quantity of free water found in the tanks of two other aircraft which had flown a similar route.
In summary, there was no evidence of excessive or unusual amounts of water in either the fuel or the fuel tanks on G‑YMMM. ……”


PP:- From Section 3 “Conclusions” ;

“……… Fuel

There was 10,500 kg of fuel remaining on the aircraft at the time of the 64. engine rollback, 5,100 kg in the left main fuel tank and 5,400 kg in the right main fuel tank.

The fuel onboard G‑YMMM was consistent with Jet A-1 and met the 65. Defence Standard 91-91 and ASTM D1655.

66. The fuel sampled from G-YMMM contained 35 to 40 ppm of water, which was similar to that found on other aircraft that had flown similar routes. ……….


QQ:- From Section 3 “Conclusions” ;

WARNING **** This I find very odd, if not actually mis-leading ! The “tests” were on fuel containing 90 ppm, which is not “normal” for operations, but is in the normal range for certain tests. There SEEMS to be no evidence to think that the fuel on board the flight even approached this “normal” concentration.


Fuel system testing

84 Ice can form within the fuel system feed pipes with normal concentrations of dissolved and entrained water present in aviation turbine fuel.



RR:- From Section 3 “Conclusions” ;

WARNING **** I.E. this report is supposition !

“……. 90. The properties of the ice generated during testing may not be the same as the properties of the ice generated in flight. ……..”


SS:- From Section 3 “Conclusions” ;

Other “classic” extracts (!) – which “forget” to mention that the comments are based on UNREPRESENTATIVE tests

“………92. Ice released from within the fuel pipes could form a restriction at the face of the FOHE. …….”

“……..93. Tests demonstrated that water when injected into a cold fuel flow at concentrations of the order of 100 times more than certification requirements could form a restriction at the face of the FOHE. ………”

“…….. 94. Sufficient ice can accumulate in the Boeing 777 fuel system, which, when released, could form a restriction on the face of the FOHE. …….”


TT:- From “Conclusions” ;

But having had “fun” criticising the report, it is important to note ;

“……. 97 The FOHE was the only component in the fuel system that could be demonstrated to collect sufficient ice to cause the fuel restrictions observed during the accident flight. ……..”


From Section 4 “Safety Recommendations” ;


“4.3 Safety Recommendation 2008-048: It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency should take immediate action to Consider the implications of the findings of this investigation on other certificated airframe / engine combinations.

4.4 Safety Recommendation 2008-049:It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency review the current certification requirements to ensure that aircraft and engine fuel systems are tolerant to the potential build up and sudden release of ice in the fuel feed systems.

This is the BIG ISSUE. The tests were unrepresentative and the icing phenomena not properly explained. What needs to be done is the science to understand the icing and ALL airframe/engine combinations tested.

Unfortunately recommendation 4.3 is only to “consider” not to act ! and 4.4 is only to “review” !

[S.F.L.Y]

No CVR transcription... Too bad, that would have been interesting to get a better understanding of these statements:

The co-pilot intended to disconnect the autopilot at 600 ft

and

The co-pilot initially believed he had disconnected the autopilot at the intended height on the approach in order to carry out a manual landing on Runway 27L [...] he was distracted and thus omitted to disconnect the autopilot

So the report mentions the succession of a "disconnection intent" followed by an "initial belief" which finally happened to be an "omission". I'm quite disappointed as I was expecting more information on the crew's management of this unusual situation.

[Akrapovic]

BBC News - 2008 BA Boeing 777 Heathrow crash: Air traffic control (http://news.bbc.co.uk/1/hi/uk/8505174.stm?ls)

[infrequentflyer789]

(PART TWO of TWO)
“4.3 Safety Recommendation 2008-048: It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency should take immediate action to Consider the implications of the findings of this investigation on other certificated airframe / engine combinations.

4.4 Safety Recommendation 2008-049:It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency review the current certification requirements to ensure that aircraft and engine fuel systems are tolerant to the potential build up and sudden release of ice in the fuel feed systems.

This is the BIG ISSUE. The tests were unrepresentative and the icing phenomena not properly explained. What needs to be done is the science to understand the icing and ALL airframe/engine combinations tested.


Agreed. Perhaps more importantly, these safety recommendations were made 18months ago, one as "take immediate action".

So, what have the regulatory authorities done ?

1. nothing
2. considered and decided the risk is too low / the cost is too high to be bothered doing anything
3. started research program

I'd bet on 1 or maybe 2 - and that isn't the fault of the AAIB. They don't (I believe) have remit or funding to go investigating this phenomenon beyond this accident circustances.

[ArthurR]

Listened to the transcripts on sky, All voice communication seems calm, cool, and collected, no panic, no hysterics just what you would expect. It seemed some good reporting, up until the reporter started with " if it had come down moments earlier, it would have landed on buildings ect " why do they do this, whats the point, if it had come down on the moon there would have had a problem invesigating the cause. We don't need to hear about if's, they did not happen. The crew and tower came across as true professionals, the reporter didn't.

[MrBernoulli]

ArthurR,

Forgive me, you don't 'listen' to a transcript, you 'read' it. You 'listen' to a recording of the communications. :ok:

And the recording/s mentioned a couple of posts above by Akrapovic, on the BBC website, have now been removed, today (NATS copyright stuff again?).

[ArthurR]

OK you are correct, I listened to the recordings on Sky news. :ok:

[S.F.L.Y]

he was distracted and thus omitted to disconnect the autopilot

Omission's definitions:

a mistake resulting from neglect
intentional or unintentional failure to act that may impose criminal liability if a duty to act under the circumstances is specified by law.
a failure to carry out a duty or to fulfill an act.
the act, fact, or state of leaving something out or failing to do something esp. that is required by duty, procedure, or lawIt's quite ambiguous to qualify an act as an omission in the report without further analysis.

[MrBernoulli]

S.F.L.Y.,
No CVR transcription... Too bad, that would have been interesting to get a better understanding of these statements .....The statements referred to were almost certainly gleaned from post-accident interviews with the pilot concerned. The AAIB aren't going to publish word-for-word stuff like that, are they?

[Dave Gittins]

The link to the Heathrow Tower feed before, during and after the event (2 mins 31 secs in all) worked a moment ago and credits NATS with copyright.

[BitMoreRightRudder]

SFLY

You seem disappointed that the report fails to criticise the flight crew in any way. Maybe there is a reason for this? They were faced with an unrecoverable situation at 500 agl. The PF disconnecting the autopilot or not had 1/40th of :mad: all to do with the eventual outcome. None of what happened can be attributed to crew error. The very best outcome they could have achieved from the point at which they realised they had a problem was to clear the airfield perimeter and hit the ground in an area of clearway with a high rate of descent. Which is exactly what they achieved. The AAIB report would have clearly stated any failure on their part had this been the case. The report didn't.

Maybe you should give it a rest? Just a suggestion :zzz:

[Ares]

Interesting interview with the pilot on BBC (http://news.bbc.co.uk/1/hi/uk/8505163.stm)

[Ancient Observer]

Rudder,
you are right. We've had 63,072,000 secs, approx., to figure out what to do. The pilots had circa 35 sec.s to figure out what to do.

As PB said in his BBC interview, he would now like to have another 20 years flying. We should be helping him do this, not sniping.

AO

[captplaystation]

I think it is about time the moderators did some "moderating".
S.F.L.Y. is like a stuck record, I really wish someone would push the "eject" button.
If he or she has no "real" appreciation of what this crew achieved in real time I suggest listening repeatedly to the ATC tape and noting how long passed between the landing clearance and the mayday, followed almost instantly by ATC transmitting that the aircraft had crashed.
It was all over in an instant, and this individual just refuses to ackowledge this and continues to incessantly harp on & on about what they "should have done"
I don't believe I am a minority of one , when I say "enough" ! :oh:

Armchair expert of the most tedious type. :ugh:

[S.F.L.Y]

The statements referred to were almost certainly gleaned from post-accident interviews with the pilot concerned. The AAIB aren't going to publish word-for-word stuff like that, are they?The statements I was referring to are statements from the report. CVR transcriptions aren't uncommon in such reports and I only regret that this time it is missing.

I don't believe I am a minority of one , when I say "enough" !You are certainly not a minority but it doesn't mean I can't discuss about what is written in this report... Why should I be banned for quoting a specific statement of the official report?

It clearly says in black and white that the FO omitted to disconnect the AP, which is quite different from a conscious decision to keep it engaged. There's a clear difference between the words "omitted" and "decided". Why can't I address the lack of further details when such a meaningful word is deliberately being used? I'm not bringing in any personal theory, I'm just stating what the AAIB released, period.

The reports also mentions that this "omission" resulted in low speed/low energy situation which didn't allow any pre-impact flare, causing a high vertical velocity impact (which btw caused most of the aircraft's damages). According to the report that was quite a costly omission.

The BEA's statement about the "omitted" concorde's spacer isn't neither leading to deeper analysis...

[Phil Space]

Captain still gets the credit and headlines:ok:

[Pilotinmydreams]

Marginly off topic from someone who doesn't know any better but what struck me having just listened to the ATC recording was how very professional and calm the controller was in dealing with the whole thing!

[StainesFS]

Following up on what PinmyD has just written, can I ask any Heathrow ATCOs who are PPRUNE members whether any official recognition was given to the staff involved (particularly the male controller principally featured)? This was, after all, a job well-done.

I know it could be claimed that the staff were only doing their job but it seems to me that, for instance, many/most of the honours dished out in HM's name go to people for just doing their job or hobby. I'm not suggesting an OBE for the controller (although we see some, arguably, less-deserving cases each new year/birthday)!

SFS

[boguing]

Put him on your ignore list. I have.

[Johnny767]

Did I hear correctly that the Captain is unemployed?

[BoeingMEL]

Like many in here, I had hoped that S.F.L.Y would shut the :mad: up once the AAIB official report was published. Should have known better of course.

Unique incident... neither expected nor trained for. Carried on flying the aircraft right down to the ground and (quite correctly) raised the flaps one stage to achieve a shallower glide.

Top marks to the crew. No marks to the armchair "expert".

Knob :ugh:

[captplaystation]

Yep, but by choice, having chosen voluntary redundancy, and confirmed earlier in this thread by the gentleman himself.

As a humerous aside, I love the part in the report where it states several pax took personal belongings during evacuation, and one deluded individual even shimmied back up the slide AFTER having evacuated to retrieve some item from the aircraft. :ugh:

I am sure the manufacturer of whatever it was would love to hear about it, what an idea for an ad campaign :D

Only those of us above a certain age would understand when I say " all because the lady loves milk tray " :rolleyes:

[Johnny767]

Thanks, glad to hear it was by his own choice.

[S.F.L.Y]

Carried on flying the aircraft right down to the ground The report mentions that the FO initially believed he had disconnected the AP and that he subsequently omitted to do so until the stick shaker activates 450 ft lower. My understanding is that nobody knew who was flying the aircraft during this 450 ft descent.

A very interesting CRM situation totally unexplored by the report. Why discussing it should be considered as attacking the crew?

[Nicholas49]

Having listened to that ATC transmission and watched the interview with the remarkably humble Peter Burkill on the BBC website, I just wanted to say that I really do take my hat off to all you guys who work in professional aviation, including ATCOs as well as pilots. The skill and dedication, evident here in what was obviously a distressing event for all, is simply second-to-none. :D

As for S.F.L.Y, I suggest you take step back and look at the 'bigger picture' (if you are capable of such lateral thinking). And listen to that recording again and again until you have finally digested how quickly things unfolded. You were presumably "disappointed" too by the fact he got the flight number wrong. The mind boggles. :ugh:

[captplaystation]

Having no experience on this type or indeed any FBW aircraft I have no idea of the relative "feel" of the controls A/P engaged or disengaged.
Given the situation they found themselves in , I don't find it too surprising that they could have missed this, assuming the control feel is similar.
On something like a B737 it would be fairly self evident , as the controls (even in CWS) do not feel the same, and anyhow the aircraft would have wandered off on a tangent, but with FBW, gust alleviation, and all these other boxes of tricks between you & the hardware ? perhaps someone experienced on type can tell us.

[MATELO]

Quote: ""if it had come down moments earlier, it would have landed on buildings ect " why do they do this, whats the point""

To sensationalise a rather mundane answer to a serious problem I should imagine.

[MATELO]

Quote SFLY- "It clearly says in black and white that the FO omitted to disconnect the AP, which is quite different from a conscious decision to keep it engaged"

Faced with 700 feet of air before bellyflopping onto houses below, it may well be easy to "overlook" disconnecting the autopilot if one is fighting to keep the aircraft airbourne.

[bearfoil]

Anyone with the engineering data that backs up the tube trimming exercise? Because I see it as a thermal solution to a mechanical problem. When the oil's cold, (let-down, cold-soaked cruise,) it will melt icebergs ahead of the Titanic?

The problem is defined as Ice related; no new research is available to mitigate what is demonstrably a potentially life threatening occurrence.

Of course the tubes are the bottleneck, they still are. An elegant "solution" to be sure, but for which problem?

Why not a wet particle separator upstream the "heater"? :ugh:

bear

[bearfoil]

S.F.L.Y

Ok.....NOTED.

[overthewing]

The statements referred to were almost certainly gleaned from post-accident interviews with the pilot concerned. The AAIB aren't going to publish word-for-word stuff like that, are they?

Transcripts of the Colgan cockpit recordings were made available, word for word.

[DC-ATE]

Well, the final report is now 'official' and we can all now start to pick it apart if we choose. I stated very early on in this thread that I didn't like the idea of the crew electing to raise the flaps a notch. This could ONLY cause a descent rate greater than what existed at the time. Raising the flaps that close to the ground is a 'no-no' in my book. I've been in an airplane when the flaps were raised by mistake, and believe me that "sinking" feeling is one you do NOT want to feel in an airplane close to the ground. And we were at take-off power. We did not hit the ground, but the 'pucker' factor was something else !!

I feel that while they might not have made the runway, the descent rate would have been less and consequently, the damge less, had they left the flaps alone. However, being as how no one was injured in this accident, there really isn't much more we can argue about now except if one is ever faced with this situation again in the future, I hope they will NOT raise the flaps to try and gain a little extra distance.

OK.....let the 'flames' begin.

[DB64]

SFLY

I've followed your comments on a number of threads and all I can ask is; 'what's your problem with BA?'

I'm not a pilot, my expertise is communication and the subtext of all that you write leads me to the conclusion that you have personal issues with BA.

Did they turn you down? If so, let it go.

[26er]

StainesFS post 2869

I agree with your sentiments about gongs and honours for doing one's job but I seem to remember that years ago when a BOAC 707 crashed at LHR shortly after t/o the stewardess was awarded a posthumous George Medal and John Davies was given an MBE for his air traffic controlling of the situation.

[bearfoil]

DCATE

I learned never to raise flap on G/A unitl Pos ROC and then slowly. I learned not to chase Glideslope without engines as well. But I've never flown anything bigger than my house. I too posted that sink would follow a retracting flap. No flames from me. However, I also learned not to criticise success. This whole deal is mx.

bear

[captplaystation]

DC-ATE, in the report they seem to think that had the flaps remained @ 30 they would have landed 50m sooner, and ploughed through various antennae.
The effect of this has not been calculated, but it is being assumed substantial damage may have been caused to the airframe.
So, like so many aspects of this approach, including the "fixation" of some that they reduced below best L/D, missed the autopilot etc etc, generally held wisdom was not recognised/ acted upon, but the final conclusion ? Result ! :ok: So WTH ?

[KiloMikePapa]

DC-ATE

Quoting from the report:
The aircraft manufacturer carried out an analysis of the final approach of G‑YMMM’s accident flight to establish the effect of selecting flap 25 at around 240 ft agl. The analysis concluded that, had the crew left the flaps at flap 30, the aircraft would have touched down about 51 m (168 ft) short of the actual touchdown on the accident flight, still within the airfield boundary.

The report also states that if they would have touched down with flaps 30 they would probably have taken out the ILS antenna with a high chance of heavier damage.

Don't you think you have to take into account the fact that flaps were reduced only from 30 deg to 25 deg? I guess this would mainly reduce drag while marginally reducing lift. It would of course be a different story if you would reduce flaps from for example flaps 15 to flaps 10.

[Basil]

DC-ATE,
I've been in an airplane when the flaps were raised by mistake, and believe me that "sinking" feeling is one you do NOT want to feel in an airplane close to the ground. And we were at take-off power. We did not hit the ground, but the 'pucker' factor was something else !!
Which aircraft and what do you mean by 'raised'?
if one is ever faced with this situation again in the future, I hope they will NOT raise the flaps to try and gain a little extra distance.
Not the conclusion of the accident report.

On the big jets I've flown the go-around procedure is:
Max thrust
Flap 20 (thats TWO notches up from the land setting of 30 and is executed IMMEDIATELY)

Never noticed any 'sink'.

[misd-agin]

I have no issues with BA. None. OK, I'll admit, I don't care for the F/A's red, white and blue striped shirts. Minor point.

I don't agree with S.F.L.Y.'s focu on 'omission'. If you plan to fly a visual, hand flown, approach, and get distracted and don't turn the A/P off, your actions fit the definition of an omission. Big deal.

As a pilot I'm very disappointed the pilot corps will learn nothing from this report regarding maintaining Vref, or allowing the a/c, IMO, to prematurely slow to achieve the best glide performance.

Also, no explanation about the value of retracting flaps at Vref, as opposed to a much lower speed, and the performance increase(?) that might be achieved.

And the pushover at 200'? What impact did that have on the a/c's sinkrate? Would the next crew that this happens to be better off staying at stickshaker or pushing over at 200' to stop the stickshaker? How much altitude does an airliner need to achieve an increase in airspeed to offset the increased sinkrate?

Yes, the crew was in a desperate situation. That doesn't mean that we shouldn't research their actions, granting them some benefit of doubt due to the nature of the event, to figure out what the appropriate actions are.

Our profession demands a critical analysis of events to help generate improved outcomes in the future.

[misd-agin]

Basil,

Two different scenarios -

On a g/a, as you stated, you're increasing thrust. At the same time you are also rotating to an increased pitch attitude. A sink is never noticed.

The other situation is with fixed power, pitch, at very low airspeed, and then retracting flaps.

[rog747]

i have followed this thread for most of the 2 years but sorry i cannot remember if re-flying the same flight in the sim but without raising the flaps a notch got them on the runway ok?

did it or did it not please?

thanks

[DB64]

Misd

From what I have followed that seems to be the case...a bit of 'there but for the grace...' followed by, 'how can we learn from this and improve?'.

As far as I have seen SLFY's comments were more postural, i.e. 'I would have done xyz, aren't I so clever'. Perhaps not his/her intentions but if so some classes in humility wouldn't go amiss.

[Basil]

I cannot help feeling that the greatest omission from the accident report was the failure to thank our contributers for their selfless and assiduous devotion to providing the investigators with the detailed advice borne of PPRuNe experience without which the document would doubtless be short and lacking in substance, which oversight will, I am sure, be corrected in any future publication of the report.

Should have put this in: ;)

[Basil]

From the report:
1.16.1 Effect of flap selection
The aircraft manufacturer carried out an analysis of the final approach of G‑YMMM’s accident flight to establish the effect of selecting flap 25 at around 240 ft agl. The analysis concluded that, had the crew left the flaps at flap 30, the aircraft would have touched down about 51 m (168 ft) short of the actual touchdown on the accident flight, still within the airfield boundary.
and:
Had the flaps remained at flap 30, the touchdown would have been just before the ILS antenna, but still within the airfield boundary. The effects of contact with the ILS antenna are unknown but such contact would probably have led to more substantial structural damage to the aircraft.

[DC-ATE]

Basil -
Which aircraft and what do you mean by 'raised'?

It was a DC-6 and by 'raised' I mean retracted. They were at the Take-off setting and the FE retracted the flaps instead of the gear. [You'd have to know the layout and handles on the DC-6/7 to understand.]

Basil - Not the conclusion of the accident report.

I know that was not a 'conclusion' of the report; only MY conclusion.

I also understand the Go-Around Procedure. I guess I didn't make it clear that the incident I was talking about was a Take-off one. Sorry.

[splitduty]

Check post 2889. I think that answers your question.

[Basil]

DC-ATE,
Thanks for the clarification.

I have to say, on the day, I'm not sure if I'd have thought of reducing the flaps a notch.
Has anyone tried straight up to 20 in the sim?

[rog747]

yes thanks,
i must have been typing my post as he typed his lol

i also have now managed to get the aaib report open...

i think the commander here did exactly what he felt was 'right' in his
gut feeling from his flying skills...

had he not raised the flaps he was only a breath away from likely hitting the fence and deffo the app/lights,
better he got well over it and onto the grass as they did...

[sky9]

We can all debate what they could or should have done, however the fact remains that they had less than a minute from identifying the problem to touching down.

While there could be good reason to go through their actions to learn for the future, nothing should be thrown at the crew for what they did or didn't do in the circumstances. They were in a situation that was outside any training scenario and unable to draw on experience.
All the POB's walked away apart from the unfortunate individual who broke his leg.

[DERG]

Report: British Airways B772 at London on Jan 17th 2008, both engines rolled back on final approach (http://www.avherald.com/h?article=4270d893&opt=0)

[wiggy]

Having no experience on this type or indeed any FBW aircraft I have no idea of the relative "feel" of the controls A/P engaged or disengaged.
Given the situation they found themselves in , I don't find it too surprising that they could have missed this, assuming the control feel is similar.
On something like a B737 it would be fairly self evident , as the controls (even in CWS) do not feel the same, and anyhow the aircraft would have wandered off on a tangent, but with FBW, gust alleviation, and all these other boxes of tricks between you & the hardware ? perhaps someone experienced on type can tell us.



Well if you for some reason are trying to manhandle the controls on a triple with the A/P in you'd certainly notice, in the same way as if you tried to manhandle a 747 with the A/P in ( the 777 I fly doesn't have CWS, is it even an opton?). In my experience you only really notice the fact that the 777 is FBW if you get close to the edge of the envelope ( in the sim I hasten to add), when the various protection features start to kick in. Otherwise it behaves and feels like a conventional aircraft...then again of course it does, it's a Boeing :ok:

[derbyshire]

I cannot help feeling that the greatest omission from the accident report was the failure to thank our contributers for their selfless and assiduous devotion to providing the investigators with the detailed advice borne of PPRuNe experience without which the document would doubtless be short and lacking in substance, which oversight will, I am sure, be corrected in any future publication of the report.

Nice one Basil!

[Hedge36]

Gentlemen:

Can someone give me an idea of the inside diameters of the fuel piping in question here? Having read the entire thread as well as the accident report, I don't see where it's mentioned (though I'm ill at the moment and may have missed it).

[Burger Thing]

DC-ATE,

on a MD-11 for example, if you are on a 2 Engine approach and loose a second engine on short final, one of the Memory Items is to raise the flaps from 35 to 28. In my experience, changing the flaps from a intermediate approach setting to the final landing flaps, has more to do with stabilizing speed and power by increasing drag, whereas lift changes not that much.

So IMHO the BA did absolutely the right thing by raising the flaps one notch. Lift (and induced drag) would have changed relatively little - rather the parasite drag reduced.

The crew were being faced with something they were not really trained or prepared for - especially at the end of a tiring long haul flight. Everybody walked away. I have the deepest respect for the BA crew, ATC and the rescue services. :ok:

BT

[misd-agin]

The lift drag benefit can be examined by checking stall speeds. On every airliner I've checked(6 types), the first notch of flaps reduces stall speed by 50-60%.

Obviously the greater the deflection the more drag vs lift is created.

Any old school fighter pilot can tell you about the value of leading edge devices. "Hard wing" wasn't your friend in a turning(ie high AOA) fight.

[bearfoil]

You must have read Boyd.

[phil gollin]

DERG,

That report is not a very good summary, and certainly even ignores to main report's glossing over of the actual water content issue.

.

[misd-agin]

post 2898 Basil asked about retracting flaps straight to Flaps 20.

Basil,

Vref 135 from the 777 performance pages is for a 440,000 lbs a/c(I don't recall BA 038's weight).

Stall speeds at 440K -
Flaps 30 108
Flaps 25 110
Flaps 20 115

The flap retraction was done 115-118 kts(I've seen/recall different numbers). If the 777 would allow it there's a chance that a retraction to Flaps 20 at those speeds could have triggered a stall. I have to believe, based on Vso multipliers, that the AOA would have been mucher and I'm guessing it would outweight any configuration drag reduction.

I'd believe that an immediate retraction to Flaps 20 at Vref might be the best plan. Sadly, the AAIB report doesn't give the next guys any knowledge.

How quickly can guys be expected to react? With training and awareness it could be done fairly quickly. How quick does a trained pilot apply rudder with an engine failure? ;)

For non pilots the difference for most Boeing a/c(that I know of) and I'm assuming Airbus' Flaps 2 is that the leading edge slats are in the mid, or takeoff, configuration. Most single engine configurations are based on mid/takeoff slats to reduce the drag associated with greater flap extensions.

My previous post explained how the largest stall speed reduction occurs in the first flap position(Flaps 1, Flaps 2, Slats EXT, etc). The last flap settings are just the opposite, mostly drag, with little stall speed reduction.

That is also why, as Basil mentioned, Flaps 20 is an important step in reducing drag, with a relatively small stall speed increase, to allow the a/c to accelerate rapidly during a go-around.

[misd-agin]

"You must have read Boyd." - bearfoil

Ah, brings a smile to my face. Learned his concepts, didn't all G pullers, before I read his book.

I love telling Marines that I have great respect for their branch of the service, especially since they so willing put a statue of a USAF fighter pilot in front of their leadership school. "B.S.!" is often the internal, and sometimes external, reaction.

Then they research it.:ok:

[S.F.L.Y]

How quickly can guys be expected to react? With training and awareness it could be done fairly quickly. How quick does a trained pilot apply rudder with an engine failure?This is certainly why Boeing issued recommendations on monitoring automated approaches which insists on mandatory manual override as soon as an automatism default is identified.

Retracting flaps from 30 to 25 improves the aircraft L/D "global" configuration, but you still need to fly the right speed to get the best of this new configuration. Flying best L/D speed at flaps 30 will take you further than flying minimum speed with flaps 25.

It's exactly like on a go-around: retracting flaps is improving the aircraft global aircraft config but you still need to fly the right speed to get the best GA performances.

In this particular case the captain's decision to retract flaps reduced the poor gliding performances resulting from flying at minimum speed.

The report clearly demonstrate that it was better than doing nothing, but it sadly fails to show what would have been the benefits of controlling the airspeed.

[rog747]

Safety Recommendation 2008-047
It is recommended that the Federal Aviation Administration and the European Aviation Safety Agency, in conjunction with Boeing and Rolls‑Royce, introduce interim measures for the Boeing 777, powered by Trent 800 engines, to reduce the risk of ice formed from water in aviation turbine fuel causing a restriction in the fuel feed system.

it goes onto say...

In addition, an engine response non-normal procedure was added to provide a procedure should the engine fail to respond to a thrust application.
The procedure called for the thrust levers to be set to idle for 30 seconds,
after which each engine thrust lever is moved to max thrust to ensure the restriction has cleared.

oh....
30 seconds....? erm like you have 30 seconds to wait when your are 450' AGL
at 108 kts and both engines no longer have any ooomph in them and the staff car park badges in the windscreens are easy to read hmmmm...

[PETTIFOGGER]

phil gollin (http://www.pprune.org/members/142378-phil-gollin)
I'm amazed.
I find the report extremely annoying.

I'm not and I don't. I believe the AAIB's report to be well researched, well written and comprehensive in scope. I believe that they have reached the right conclusions and have provided sufficient analysis to justify those conclusions. For those of us with more than a passing interest in fluid dynamics, more detail would have been gratefully read. But one has to draw the line somewhere, and I think that they have got the balance of the report just right. It is a QED report in my view.

Concerning the flap retraction, some would do well to read Capt P Burkhill's thorough explanation of his feel for the 777. Non believers can do the numbers or get someone to do them for you. Or just believe the AAIB. A difference of 51 metres is significant, and life saving in this situation. He obviously had no time to do the numbers; he knew from experience and instinct. A good man.

Anyone baying for the CVR, forget it. The crew probably swore, said good-bye to their loved ones, before they knew they were going to make it. What do you expect?

About the fuel restriction, I can understand that some might be surprised by this and may have a preference for other theories; others may accept it, but doubt the AAIB’s reasoning. This too is entirely understandable and normal. Water occurs naturally in fuel (from the atmosphere), on the ground and at 30,000ft. There is nothing new about that. But fluids can be tricky, especially water, and get trickier with changes in temperature and when ‘piped’. Anyone with an intimate knowledge of Fluid Dynamics knows that. That is why the AAIB were able to focus on this, and why myself and others suspected the fuel delivery architecture some time ago. AAIB, Boeing and Rolls Royce all accepted that a modification of the FOHE was needed, and I understand the all Trent 777 have now been fitted with modified FOHEs. So that's it.

[DERG]

That report will prolly be read by a wider audience than the official version and of course it is an interpretation. It has pics and good precis and is objective.

For people like me it is wunnerful because I can see the parts and understand what went on. It makes sense.

I don't think this will happen again due to the modifications made as result of this accident. That is all I seek. The outcome is postive and the world is safer..whatmore could anyone want?

[S.F.L.Y]

Anyone baying for the CVR, forget it. The crew probably swore, said good-bye to their loved ones, before they knew they were going to make it. What do you expect?


Instead of swearing some crew communication could have helped to detect that the AP failed to be disconnected as it was believed.

[NigelOnDraft]

I'd believe that an immediate retraction to Flaps 20 at Vref might be the best plan. Sadly, the AAIB report doesn't give the next guys any knowledge.Aerodynamic basics would state that there is no set "rule" you can derive. The higher you are, the lower the optimum flap setting would be. As you get lower the lower stall speed with more flap outweighs the drag.

It is not the AAIB's job to (re)write handling manuals: The purpose of the AAIB is:

"To improve aviation safety by determining the causes of air accidents and serious incidents and making safety recommendations intended to prevent recurrence"
...It is not to apportion blame or liability.

Chief Inspector They went as far in this report to analyse the FC actions as were relevant to the accident - in short, a no notice untrained for emergency, and their actions pretty much resulted in an optimal outcome:...they kept the aircraft flying and under control so that, at impact, it was wings level and at a moderate pitch attitude

Fundamentally this is a design/engineering accident, and little to learn from the FC pov - IMHO it is impractical to expect "drills" to be produced for every eventuality - especially since in this type of accident they would need to be "memory"...

Just my 2ps worth ;)

NoD

[S.F.L.Y]

IMHO it is impractical to expect "drills" to be produced for every eventuality

It's not a matter of different eventuality but basic fundamentals. Losses of thrust during initial climb requires to control:

- Safe flight path
- Optimum speed
- Configuration (drag)

There is basically no difference when this happen during an approach, there is no need for a "special" procedure. I regret that the AAIB didn't consider including few lines about it.

[idle bystander]

Instead of swearing some crew communication could have helped to detect that the AP failed to be disconnected as it was believed.


which will, no doubt, bring down the wrath yet again of the god-like pilots on poor old sfly. But, people, she has a point. Throughout my reading of this thread I've been amazed by the pure coolness displayed by these guys in leaving the a/p engaged until it tripped at stick-shaker. What faith in automation!

and now it turns out the F/O "omitted" to disengage it. That doesn't sound like a deliberate (and oh so cool) action.

And surely you guys out there see the point. Might it have been better to hand-fly from the moment the problem was identified? Perhaps not. Certainly the outcome could hardly have been better. But I think we'd all like to know.

[misd-agin]

Pettifogger -

The transcripts for USAIR 1549 are available. 3+28 (208 seconds) from impact to impact.

FO Skiles - Oh, sh*t
CA Sully - Oh, yeah

After that they were too busy to make any personal comments. Sully has said that his family never crossed his mind.

I would guess that the BA038 crew had the same focus.

[xavier95]

SFLY
95% of pilots will follow the flight director if flying manually. The flight director will be trying to keep the aircraft on the ILS, exactly what the AP was tryting to do. So why increase the workload, when trying to faultfind an emergency for which there is no drill. For the 15-20 seconds that elapsed between when the FO intended to take out the AP, and when he did, the difference in flight path is hardly worth talkingabout, if you want something pointless to contemplate, why not have a heated debate about whether they should have asked all the passengers to move to the back of the aircraft, in an attempt to reduce control drag!

[phil gollin]

Pettifogger ;

" .........the AAIB's report to be well researched, well written and comprehensive in scope. I believe that they have reached the right conclusions and have provided sufficient analysis to justify those conclusions. ......."

The report is hardly "comprehensive in scope" as it does not even begin to try to cover representative tests of the presumed actual fuel/water mixture in the plane at the time of the accident.

Likewise their "analysis" is non-existent as they totally dodge this issue.

The report screams out both a lack of rigourous testing and avoidance of the huge cost that would be involved in both undertaking such research and then applying it to ALL airframe and engine combinations.

Releasing a report with such glaring gaps is plain weird.

[Speed of Sound]

Vref 135 from the 777 performance pages is for a 440,000 lbs a/c(I don't recall BA 038's weight).

410,880 lbs

SoS

[xavier95]

This is the longest, and most comprehensive, AAIB report I can recall. I guess as a taxpayer I ought to be glad that the AAIB does not have to pander to idiots who want the report to explain the movements of every component throughout their entire life, the movement of the planets and the variations in the planetary magnetic fields.

[Landroger]

While the actions of the crew in the last, doubtless frenetic, seconds of the flight are both interesting and admirable - so far as I am concerned - I have to say I share Phil Gollin's concerns that 'eyes have been taken off the ball.' His well researched and knowledgable post should really have put questions of flaps raised or not, to one side. The reason those two gentlemen, plus all their crew and passengers were in that terrifying situation is because two of the most beautifully engineered machines for producing thrust, didn't. Both at the same time, give or take a few seconds.

I joined this forum because the circumstances of BA038 were, to this uninvolved bystander engineer, quite simply; staggering. Unbelievable. And yet today the report uses the word 'probably'. Entrained ice in the fuel probably caused the engines to 'choke' simultaneously. However, unless I've missed some big numbers somewhere, it seems quite extraodinary that so little water could choke such big engines at such a critical moment in the flight.

It appears to my untrained eye that the engines were consuming fuel at varying rates - in the last twenty odd seconds - but between one and two kilograms per second. Phil Gollin's text stated that it was estimated that there was a total of 5.14 Lt of water in all the fuel in the aeroplane at take off and sucked in during the flight. It just seems too little, because if all the water in the tanks suddenly arrived at the delivery system in the last few seconds, it would still only represent about 10% of the fuel being consumed at the time.

Since entrained water and ice in fuel systems has been endemic all through the history of high altitude, high speed flight and certainly during the whole operating career of the 777 - a lovely aeroplane to my mind - why hasn't it happend before?

Perhaps it has been decided to apply the principle of Occam's Razor and accept that ice is 'probably' the cause. Although I apply the principle myself in my own job often enough, the pricking of my engineer's thumbs suggests to me that something, somewhere has been forgotten.

Roger.

[WojtekSz]

Mmmayday38 (http://www.pprune.org/members/293139-mmmayday38):
for some it is still not possible to accept that gut feeling flying may actually produce best possible results.
I still believe that your post http://www.pprune.org/5426378-post2761.html is a glamorous example of humble and professional human side of flying.

thank you!

long time ago J.Conrad wrote a book on sailors - 'Lord Jim' - from which i have learned one thing: one can not tell how he would have behaved in given situation until he would have lived through such experience himself.

hopefully the Report's recommendations might help in preventing it happening ever again...

[DC-ATE]

Burger Thing -
on a MD-11 for example, if you are on a 2 Engine approach and loose a second engine on short final, one of the Memory Items is to raise the flaps from 35 to 28.

That could very well be. BUT.....you still have an engine left for some thrust. BA038 had NOTHING.

[Knackered Nigel]

Well done Peter and John in doing your best in such limited time. I cannot imagine being in the same position.

Additionally a fantastic job by ATC in response. Just heard the audio on BBC. Chilling stuff but well handled.

Stop criticising and let's move on.

[Feathers McGraw]

Landroger

I recall that, from much earlier in the investigation, data on 777 engine and aircraft handling was checked for many hundreds of thousands of flights (or was that flight hours? Not sure) and the parameters found for BA038 and G-YMMM's last journey were right down at the very tail of the distribution with the lowest rates of climb and hence the lowest incremental thrust/fuel flow, coupled with a very long flight at unusually cold OAT followed by an unusual uninterrupted continuous descent into LHR with only one power application above idle which rapidly resulted in the thrust reduction seen.

While I can see Phil Gollin's point about things that have been left out of the report, it is clear that such a weight of unusualness is bound to have effects that may never have been seen before.

I also think that the volume of "ice" - by which I mean some sort of semi-frozen ice/water/fuel mixture may well exceed that theorized by a simple consideration of the effect of freezing those 5.14 litres of water, but even then the crucial pipes are quite short so a little "ice" clearly didn't need to go such a long way.

But, clearly more to be learned.

The question is, can anyone be expected to have the strength of character required to investigate further and then, if the facts show it to be necessary, convince the industry to spend what could be a very large quantity of money to correct the behaviour of every fuel system on the planet?

[chippy63]

Occam's razor (or Ockham's razor[1]), entia non sunt multiplicanda praeter necessitatem, is the principle that "entities must not be multiplied beyond necessity" and the conclusion thereof, that the simplest explanation or strategy tends to be the best one. The principle is attributed to 14th-century English logician, theologian and Franciscan friar, William of Ockham. Occam's razor may be alternatively phrased as pluralitas non est ponenda sine necessitate ("plurality should not be posited without necessity")[2]. The principle is often expressed in Latin as the lex parsimoniae (translating to the law of parsimony, law of economy or law of succinctness). When competing hypotheses are equal in other respects, the principle recommends selection of the hypothesis that introduces the fewest assumptions and postulates the fewest entities while still sufficiently answering the question. It is in this sense that Occam's razor is usually understood. To quote Isaac Newton, "We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances. Therefore, to the same natural effects we must, so far as possible, assign the same causes."[3

More on Wiki ( from which this intro is lifted) for anyone interested.

In the modern idiom, keep it simple, stupid.

[PETTIFOGGER]

misd-agin
Pettifogger -

The transcripts for USAIR 1549 are available. 3+28 (208 seconds) from impact to impact.

FO Skiles - Oh, sh*t
CA Sully - Oh, yeah

After that they were too busy to make any personal comments. Sully has said that his family never crossed his mind.

I would guess that the BA038 crew had the same focus.No doubt. But when sliding along on the grass? Have a look at this at 2.08 to 2.16
BBC News - BA crash captain: 'I thought it was my time to die' (http://news.bbc.co.uk/1/hi/uk/8505239.stm)
This clip also contains Capt. P Burkhill's recollection of his flap/drag decision and observed consequences.

[cargosales]

As a humble SLF and one-time glider pilot,

Having read this thread and various offshoots, and having just listened to the ATC recording, which highlighted how incredibly calm and measured the responses were from each of the people/groups involved, may I just say how much I was impressed by the actions of all those involved in this incident. Truly professional !!

There are those who post here who will always try to seek blame and unfairly denigrate individuals, regardless of the facts. To them I would say **** ***

CS

[lomapaseo]

phil gollin

The report is hardly "comprehensive in scope" as it does not even begin to try to cover representative tests of the presumed actual fuel/water mixture in the plane at the time of the accident.

Likewise their "analysis" is non-existent as they totally dodge this issue.

The report screams out both a lack of rigourous testing and avoidance of the huge cost that would be involved in both undertaking such research and then applying it to ALL airframe and engine combinations.

Releasing a report with such glaring gaps is plain weird.
P

Your last statement desrves a rebuttal

It's not the job of the investigating agency to research and develop all possible contributors in future accidents. It is generally considered that an investigation report has done a fair job if its recommendations are timely and sound enough to make it unlikley that the accident will be repeated before the designer-regulator has addressed the issues.

Sometimes it's important to be aware of the fine line between design intent, regulation and after-the-fact discovery. Lessons Learned

[Landroger]

I recall that, from much earlier in the investigation, data on 777 engine and aircraft handling was checked for many hundreds of thousands of flights (or was that flight hours? Not sure) and the parameters found for BA038 and G-YMMM's last journey were right down at the very tail of the distribution with the lowest rates of climb and hence the lowest incremental thrust/fuel flow, coupled with a very long flight at unusually cold OAT followed by an unusual uninterrupted continuous descent into LHR with only one power application above idle which rapidly resulted in the thrust reduction seen.


I accept that BA038's flight profile might have been unusual, or rather an unusual concatenation of ordinary events, the chance pattern of which placed them at an extreme point on the 'bell curve'. But even the extreme position on the curve does not preclude the possibilty of bilateral 'engine failure' if say, just one extraordinary item was removed and thus something like this ought to have happened before?

I don't know just how sophisticated any tests have been, but it is not beyond the wit of man and an imaginative test rig, to reproduce the accident conditions routinely. Some aircraft components - although not a whole engine I wouldn't have thought - a quantity of appropriate fuel and reliable means of lowering the temperature of tanks, pumps, pipes and control systems. Unless and until someone has done this and reproduced the fault - where reproduce is the scientific key - it will not be possible to say we have the answer to BA038.

I think Phil Gollin has said as much, but with greater scientific weight than I could possibly aspire to. It seems that the fault condition could be achieved - intermittently - but only by forcing certain parameters well outside those thought to obtain in G-YMMM. One of which was to artificially increase the proportion of water by direct injection near to suspected critical components. (Italics my speculation.)

If this localised increase in water density was the only way to trigger the fault condition, then the fact that - according to Phil Gollin's text - ice tends to form on the bottom - coldest - part of the tank (and was extremely difficult to dislodge) suggests that this would keep the bulk of the available water away from anything vital. And even if it did in one tank, enough to choke its engine, why did it happen in the other at the exactly the same time?

All I say is, again in my opinion, that this accident was extraordinary from the start, but after all this time the answer appears to put it in the category of 'the perfect crime' and only just short of it being caused by an Alien Energy Beam.

Roger.

[bearfoil]

Landroger

I discard "holes in cheese", and Occam is more like a group vote than a tedious research into cause and effect. If I could call up the spirit of Pinkman I would welcome his input relative to water/fuel/ice.

I think you envision a puddle of Water freezing at the bottom of a tank or an elbow in the transit pipe. There is always water in fuel, that is a given. In the least amount perhaps 7ppm. Depending on piping architecture, tank pressure and boost pumps, the system is engineered to preclude clogs of solid water Ice getting to the engines. From the beginning here, from Boeings chief safety pilot to posters on this thread, a theory of migratory slurry came about that was theorised to have broken off the walls of piping to flow with the current to end up at the FOHE face, where it plugged fuel flow after several seconds of full chat, a matter of collected data on the record. GE versus Pratt, Chinese versus US or Brit fuel, bowser this, sumping that, or not, and the procuring cause of the problem was?????? UNKNOWN. The theory was not duplicable, and the mandated fix involves a little closer shave to the face for the fuel tubes in the HE cannister. Evidently, Boeing and FAA are confident the fix will prevent further occurrence of quiet Trent syndrome. Since nothing in the report explains how this happens, one may ask really?

bear

[infrequentflyer789]

I joined this forum because the circumstances of BA038 were, to this uninvolved bystander engineer, quite simply; staggering.


You aren't the only one.


Unbelievable. And yet today the report uses the word 'probably'.
That shouldn't be a surprise, it wasn't to me. Since the early interim reports it's been made clear that there was some sort of obstruction in the fuel system, that disappeared before investigation. Ice / wax / slush typically doesn't stick around to be investigated, and can form and behave "randomly" making reproducible experiments practically impossible.

Realistically, "probably" was always as close as we were going to get.


However, unless I've missed some big numbers somewhere, it seems quite extraodinary that so little water could choke such big engines at such a critical moment in the flight.
What you may have missed is that the suspect is not water ice, in fact I think the AAIB may have confused many by referring to it throughout as "ice". It is actually a slush made up of fuel and water, at above the waxing point of the fuel but below the freezing point of water. It isn't clear that this is a previously known phenomenon - it isn't a well researched state of fuel, if it was known about at all.

The reported tests showed both that a spoonful of water could create enough of this "ice" to block the FOHE, and that larger quantities of this "ice" (more than enough) could acrete on pipework over time at low fuel flow rates.


Since entrained water and ice in fuel systems has been endemic all through the history of high altitude, high speed flight and certainly during the whole operating career of the 777 - a lovely aeroplane to my mind - why hasn't it happend before?
AAIB: "Data mining showed that the accident flight was unique amongst 175,000 flights..."

That was a big data excercise, and found no other comparable flights, so we have no idea how many flights you would need before you would be likely to see a repeat of these circumstances. Quite possibly more than the total 777 flights to date.


Perhaps it has been decided to apply the principle of Occam's Razor and accept that ice is 'probably' the cause. To apply Occams Razor, you need to have other hypotheses that also fit the evidence. I see none. Up to now I would have said that the spar-valves were still a suspect on the info we had, but I believe I see in this report the evidence on which the AAIB have ruled that out (not as clearly presented as I would like, but I think it is there).

What I do see in this report, in much more detail than we had before, is lots of elimination of other hypotheses before ending up with the "ice" as (only) probable cause, ie. "When you have eliminated the impossible...". That isn't Occams Razor - in fact it is more the reverse of it.

[infrequentflyer789]

It's not the job of the investigating agency to research and develop all possible contributors in future accidents. It is generally considered that an investigation report has done a fair job if its recommendations are timely and sound enough to make it unlikley that the accident will be repeated before the designer-regulator has addressed the issues.

Agreed and worth noting that some 18 months ago the AAIB recommended that the regulatory authorities consider, as phil gollin says: "undertaking such research and then applying it to ALL airframe and engine combinations."

That ball has been in the regulators court for 18 months now, and it is out of order to blame the AAIB if the regulators haven't done anything with it.

[Willie Everlearn]

The CBC here in Canada are reporting that the crew of this flight have been off duty since the accident and the Captain "is looking for work".
:confused:
Do I conclude from this that;

A. BA severed the crew
B. The Canadian media are just as good at reporting aviation stories as everyone else
C. This crew have decided to "moonlight" as industry saviours
D. Fiction is stranger than fact

Willie :ugh:

[Me Myself]

Don't know about the F/O's, but the captain resigned last August 2009 and if he is looking for work, then we'd all be doing a good deed in closing that thread that is in no way helpfull.

[Blythy]

Aside from the ice stuff; there's some interesting theoretical questions that come as a result of this:

-does a three degree glideslope have enough of a safety margin for an approach vector. Would a higher slope with a lower throttle setting (hence less difference should thrust fail) be safer with regard to a loss of power on finals, or is the requirement for a better go around response more pressing (presumeably, it's faster to go around with a lower glideslope)

-Are runway safety margins big enough; should there be some sort of retardation surface at the end of runways in the event of such an incident or is grass good enough? What if it had been frozen?

-How the hell did a guy make it back on board to retrieve stuff? I know the slide at the rear right door was almost horizontal from pics I remember seeing but when did he get a chance?

-Good boeing quality control I see; with plastic ice scrapers being found in the tank; and FOD having a possible effect on the water scavenging in the tanks.

[Burger Thing]

That could very well be. BUT.....you still have an engine left for some thrust. BA038 had NOTHING.

Yes, of course... But the aerodynamic principles are the same. The concern is to get rid of the parasite drag. On a heavy jet with the landing gear down and full landing flaps and no thrust you decent like a stone at VREF :rolleyes: Or you bleed off your speed down to the speed shaker in no time if you maintain a 3 deg G/S, like the crew of the TA B738 in Amsterdam experienced with their throttles closed at idle.

The difference in stall speed and hence available lift is not much at the later stages of the flap settings - but the difference in drag is enormous. Which is handy to have, if you got your engines running. It will require a rather high power setting, which gives you a much faster throttle response.

So IMHO even if they couldn't maintain the speed and raised the AoA to get more lift and therefor increased induced drag, they drag was still less then the parasite drag you have with full flaps. I think the report also mentioned, that if they had maintained the configuration, they would have touched down a bit earlier. Which seems to support my thoughts above.

[S.F.L.Y]

The difference in stall speed and hence available lift is not much at the later stages of the flap settings - but the difference in drag is enormous.This isn't correct, as you can see on the following illustration (B787), the later stages of flaps are having a lower impact on the L/D performances than the earlier. This means lift benefits are more predominant over drag in this stages than in the earlier.

http://www.lissys.demon.co.uk/samp1/lspb.png

While L/D improvements resulting from flap retraction are visible on this illustration, you have to keep in mind that this is valid provided that the aircraft flies the appropriate Vref. In other words, compare the little L/D improvements that you obtain through flap retraction with the major L/D reduction caused by flying at the minimum speed and you will find out what was the most efficient way to control gliding performances. The lack of speed control caused greater performance deterioration than the flaps retraction could improve.

It's exactly like trying to clear an obstacle during a climb by retracting the landing gear while the aircraft's speed is far from Vx. It only reduces the "negative" effects.

[Mr Optimistic]

I admit this isn't my line of work but doesn't a given configuration give a given L/D ratio which defines the best flight path angle (best in terms of range) and the crew have to find an angle of attack which achieves the flight path angle with the speed following from there ?

[S.F.L.Y]

doesn't a given configuration give a given L/D ratio which defines the best flight path angle (best in terms of range) and the crew have to find an angle of attack which achieves the flight path angle with the speed following from there ?
For each config you have an optimum L/D angle of attack. Deviating from this value will reduce the L/D ratio.

[BarbiesBoyfriend]

I agree that on a 3 degree slope an a/c is always going to be short of energy if it has a complete power loss.

So why not fly a bit faster?

What, for pitys sake, is the point of flying at Vref+5, 5 miles (or more) out?

Is it SO hard to slow down when near to the runway?

The extra 'handling speed' is useful too.

[L337]

What, for pitys sake, is the point of flying at Vref+5, 5 miles (or more) out?

Is it SO hard to slow down when near to the runway?

Because a stable approach is a fundamental tenant of a safe operation of a large commercial airliner. Accurate speed control is absolutely vital to putting the aeroplane down in the right spot and getting it safely stopped.

The extra 'handling speed' is useful too.

It is? Why? Are you suggesting Boeing Airbus et al need extra speed to handle better? Whatever better is...

Why are you posting on a subject and thread you clearly have absolutely no knowledge of?

[BarbiesBoyfriend]

L337

I have 10000 hours in commercial ops.

Where I work you have to be stable by 500' but they teach people to fly Ref+5 for miles before that.


Do you know what 'handling speed' is? It's not type specific.

As for flying a bit faster: I think most folk could and still be stable at 500'

Maybe you'd struggle on your type? I know not. Depends on the type. And the pilot.;)

[L337]

I cannot believe for one second that you have ever flown a heavy jet. And whilst we are willy waving. I am a 747-400 Captain, I have well over 20,000 hours of which 7000 are on 747s.

I sure would struggle to be safe if I flew as you suggest.

[BarbiesBoyfriend]

Well, there you go then. Don't carry any extra speed. I'd hate you to have an accident!;)

An extra 5-10 kts would likely have got the 038 on to the runway, is all.

My point is simply that Ref+5 is great at 500' -and you need to make it so, because nowadays you're not trusted to slow down any later.

But why at 4 miles? I mean -are you going to land out there?

(Biggest I've flown is MTOW 48000kg. Small to a Jumbo.:))

Just a wee edit to add that we can be at Vref+19 at 500' and still be officially 'stable'.

[captplaystation]

L337 , well, I have to say you are very fortunate to always fly to destinations where there is no, or very lax ,speed control.
At LHR/LGW/STN and many many major European airports the requirement is 160 to 4.(indeed there are some that ask 180 to 4 which is exaggerating just a little)
So, if you are able :rolleyes: 25kts to be bled off, in the case of this 777 , in the last 4mls.
Well, in my mere 16500hrs I seem to have observed most of my colleagues remaining safe whilst complying with that, what are you missing ?

[Pinkman]

The spirit of Pinkman is still alive and lurking - just didnt have much else to add and I am not a told-you-so type of guy. Also I got to the stage where I was a trifle worried about the men in black knocking at my door at 4am. But... since you ask.... I still have questions, although I accept they will never be answered.

We are told that the fuel came from South Korea (possibly the Yosu refinery but it doesnt say) and we know that they ruled out FAME (biodiesel) contamination. I wasnt surprised at the analysed freezing point when we were told that the fuel was Chinese RP-3 (Jet Fuel number 3). Thats entirely consistent. When they corrected the supplier, I was slightly surprised that the FP was -57 Celsius out of S. Korea on a consignment that was certified as Jet A-1, but in a 2008 IFQC survey, Jet A-1 freezing points varied between -47 and -60, so I suppose its possible. But the fact that the fuel went from refinery to ship to tianjin depot and then presumably via pipeline to beijing would make me want to investigate water pickup a bit more thoroughly. That sort of transit is not unusual but does require good handling practices. Other than that - not a lot you can say. Looking on the bright side, we've had a focus on aviation fuel quality like we have never seen for years as a result of a major incident that didnt kill anyone. That HAS to be good news.

Pinkman

[Mariner9]

I happen to be looking at a S Korean Jet A-1 CofQ as we speak. FP quoted is -51C. This particular one had bacterial contamination as it happens but that's nowt to do (it seems) with BA038.

Come to think of it, one of my colleagues dealt with a major particulate contamination (again, nowt to do it seems with BA038) on an Ulsan jet cargo late last year, I'll check on quoted FP when he returns to the UK next week.

[L337]

I never for one moment suggested that I do or would ignore speed controls. I said: "a stable approach is a fundamental tenant of a safe operation of a large commercial airliner. Accurate speed control is absolutely vital to putting the aeroplane down in the right spot and getting it safely stopped."

The bulk of aircraft accidents happen in the landing phase. The major cause of landing accidents can be traced back to rushed approaches, and unstable approaches. 4 miles is 1200'. With planning it is possible to be stable at 1000, and definitely stable at 500'.

Carrying unnecessary excess speed is one cause of a unstable approach.

Recent studies show that, most CFIT accidents occur within 8nms of the airfield, and a very large proportion of these are on the centreline within 3nms.

1000' is about the last point to have energy management issues resolved in order to ensure maximum capacity for the last 3nms of the approach to monitor and manage the most exposed part of the flight.

[maynardGkeynes]

Can anyone explain why the incident happened when it did, just before the runway? Why did it not happen earlier in the flight? To me, this is just too much of a bit of luck to have been pure happenstance. It suggests human error, possibly pilot error. But what?

[cats_five]

maynardGKeynes, go read the AAIB report. That will answer your question.

[fchan]

Blythy, when asked about increasing the glideslope, admittedly mainly for noise reasons, one airline manager said, “The short answer to that is no, the aircraft is stable at 3 degrees in that intermediate configuration and just about idle thrust, so it’s about as quiet as it can possibly be and about as fuel efficient. If we steepen the approach we are actually going to have make a dirtier configuration and probably use a higher power, so it’s not feasible on a fuel savings benefit, it’s not good from a noise point of view and therefore there are no benefits from our point view.”

No doubt depends on the a/c type. That airline is a mid range operator. No 330, 340, 380, 777, 747s. etc. But can’t see any airport offering different glideslopes for different a/c anytime this side of the 22nd century.

By the way, who actually paid or will pay for the cost of the lost a/c seeing as it was Boeing’s or Rolls Royce’s (?) ‘fault’? BA, Boeing or a leasing company? I have lost the will to look back far enough in this thread to find the answer.

[5LY]

L337. Agree fully with your thoughts on stabalized approach. Further to that, if you're still scrambling to get in the slot below 1000', you're not focused on the big pic. Your focus is tunneled to something that should have been put to rest before 1000' and you'll miss one of the myriad little things that can help to let light through the cheese.

[S.F.L.Y]

An extra 5-10 kts would likely have got the 038 on to the runway, is all.

The problem was not that they didn't have enough of speed, they simply didn't control it.

[S.F.L.Y]

who actually paid or will pay for the cost of the lost a/c seeing as it was Boeing’s or Rolls Royce’s (?) ‘fault’?

Whoever it is, I'm sure they would be interested to know whether or not a softer impact could have been possible if the last 500 ft had been under control.

[bearfoil]

S.F.L.Y

Any plaintiff pushing your theory would be in deep jeopardy of losing the whole enchilada. Stick to what you know (?)

bear

[DC-ATE]

BarbiesBoyfriend - has this figured out. I always carried 5 to 10 knots extra speed "just in case". When are you 'professional' pilots going to realize this is NOT an exact science?! I don't care how many thousands of hours one has. Most of that time for 'heavy' drivers is in cruise anyway.....means nothing. It's the time below ten thousand feet "where the action is" that really counts.

[Just wondering]

Funny business this aviation thing !!

There are times when too much attention to detail will kill you and there are times when too little will kill you - same with speed on the approach - the secret is to know when to apply detail and speed.

+5-10 knots doesn't mean your destabilized but going into a short runway means you need to fly the numbers to meet the performance.

A long time ago I learned to respect the amount of hard work put in by people who did the data.

[BarbiesBoyfriend]

DC-ATE
Thanks for that!:ok:

I suspected it wasn't just little old me.

You know what, not long before we land, wait for it............

I slow down.:hmm:



btw I agree with you re hours etc. I got about 10,000 on short haul, regional ops. (big deal:})

20,000 on long haul = 15,000 reading the papers!

[DC-ATE]

Well, BarbiesBoyfriend, good luck in your career. You will make it to retirement with your attitude. Me.....I already made it.....twenty years ago. Glad I'm outta this racket !!:8

[Mmmayday38]

There are a few points that some people are struggling with so I am going to try my best to answer them:


Some people are wondering why I say there were 153 souls on board the BA38. There was a pregnant lady on board, I was told months later she successfully gave birth to her baby.




Arthur R 2856

“It seemed some good reporting, up until the reporter started with " if it had come down moments earlier, it would have landed on buildings ect " why do they do this, whats the point. [ ]… We don't need to hear about if's, they did not happen.”


I think it was good reporting by the BBC. It was a quote from myself that the BBC was reporting on that stated that I saw the impact point being ‘catering buildings, tube station and petrol station at Hatton Cross’ when the descent rate was 1800 fpm before reducing the flaps. Therefore he was simply stating what I had thought was fact. If the rollbacks had happened moments earlier, then yes, those buildings would have been IMHO in ‘fact’ impacted. Those images of where I thought the impact point was going to be helped focus my mind on finding a solution.



Ancient observer

“Rudder,
you are right. We've had 63,072,000 secs, approx., to figure out what to do. The pilots had circa 35 sec.s to figure out what to do.

As PB said in his BBC interview, he would now like to have another 20 years flying. We should be helping him do this, not sniping.”


Thanks for your continued support AO; I like the analogy. :ok:



StainesSF
“can I ask any Heathrow ATCOs who are PPRuNe members whether any official recognition was given to the staff involved (particularly the male controller principally featured)? This was, after all, a job well-done.”


I’m not an ‘ATCO’; but I can let you know that the tower controller did receive recognition from the Royal Aeronautical Society and was awarded the ‘The President’s Award’ in Dec 2008. The President’s Award is ‘an award to recognise an individual who has displayed outstanding skill and professionalism in the field of aviation and aeronautics, especially in adverse circumstances’.


DC-ATE
“I stated very early on in this thread that I didn't like the idea of the crew electing to raise the flaps a notch. This could ONLY cause a descent rate greater than what existed at the time. Raising the flaps that close to the ground is a 'no-no' in my book. I've been in an airplane when the flaps were raised by mistake, and believe me that "sinking" feeling is one you do NOT want to feel in an airplane close to the ground. And we were at take-off power. We did not hit the ground, but the 'pucker' factor was something else !!

I feel that while they might not have made the runway, the descent rate would have been less and consequently, the damge less, had they left the flaps alone.”



I know this has been answered since posting it; but to re-iterate from the report;
P.140
(impact point is the rear axle of the main landing gear which has approx 26m of aircraft in front of it and 35m behind it)
Actions of the Commander - 2nd paragraph

“The action of reducing the flap setting was prompt and resulted in a reduction of the aerodynamic drag, with minimal effect on the aircraft stall speed; it moved the point of initial ground contact about 50m towards the runway threshold. Had the flaps remained at flap 30, the touchdown would have been just before the ILS antenna, but still within the airfield boundary. The effects of contact with the ILS antenna are unknown but such contact would probably have led to more substantial structural damage to the aircraft.”

Boeing test pilots spent many a month/year flying this approach again and again in the sim…. They never achieved a better result in terms of distance covered with the conditions we had on the day. When they left the flaps at F30, they could only best get to within 51m of MMM; still 10m behind the antennae. I would not want to hit those at 108kts, would you? I was faced with a life threatening situation and this report states that I achieved a better result than if I had left the flaps alone, end of.
If you have an incident that requires you to think and react, instead of remembering a checklist, then best of luck to you. I know I am able to think positively and clearly in a stressful environment whilst facing death head on, it wasn’t in the books and never will be; but please don’t make out that it was wrong.




CaptPlaystation

“DC-ATE, in the report they seem to think that had the flaps remained @ 30 they would have landed 50m sooner, and ploughed through various antennae.
The effect of this has not been calculated, but it is being assumed substantial damage may have been caused to the airframe.
So, like so many aspects of this approach, including the "fixation" of some that they reduced below best L/D, missed the autopilot etc etc, generally held wisdom was not recognised/ acted upon, but the final conclusion ? Result ! So WTH ?”



What can I say…. Thanks for sticking up for me!
Cheers :ok:


Misd-agin
“As a pilot I'm very disappointed the pilot corps will learn nothing from this report regarding maintaining Vref, or allowing the a/c, IMO, to prematurely slow to achieve the best glide performance.

Also, no explanation about the value of retracting flaps at Vref, as opposed to a much lower speed, and the performance increase(?) that might be achieved.


And the pushover at 200'? What impact did that have on the a/c's sinkrate? Would the next crew that this happens to be better off staying at stickshaker or pushing over at 200' to stop the stickshaker? How much altitude does an airliner need to achieve an increase in airspeed to offset the increased sinkrate?

Yes, the crew was in a desperate situation. That doesn't mean that we shouldn't research their actions, granting them some benefit of doubt due to the nature of the event, to figure out what the appropriate actions are.”



This one is best put to any Boeing test pilots; as they have analysed this at length; please see my previous answer to ‘DC-ATE’.

I would also like to see written down the best way to achieve the optimum outcome.
As Boeing couldn’t produce a better result; I would say perhaps;
Leave A/P engaged until hearing the “Airspeed Low” warning. Thus maintaining G/S. Then reduce the flaps.
This worked.
If detected at an early stage then do something about it earlier; ie reduce the flap earlier.
At 1500’ agl for instance, you’d have a chance of clearing obstacles by reducing straight to F20 whilst you have the speed. Keeping F30 would not get you as far, ask the manufacturer.

On this BA38 approach though, I would not have wanted to keep F30 as it has been proved would have impacted on the ILS antennae, causing untold damage and death. The best outcome for the BA38 was no deaths, to achieve that, it was necessary to reduce flaps to F25 and so avoided the last obstacle. Had I have known that at 500ft we were not going to get power back I would have selected less flap straight away… that’s easy to see why now, but put yourself in my seat at the time with no knowledge of rollbacks or 63 million seconds (thanks AO) to think about it, and you’d have come to the same conclusion I’m sure.


ROG747

“i have followed this thread for most of the 2 years but sorry i cannot remember if re-flying the same flight in the sim but without raising the flaps a notch got them on the runway ok?

did it or did it not please?”



I have heard from other ‘Ppruner’s’ who have stated that he/she had achieved flying ‘BA38’ on to the runway in the sim, some by leaving the flaps at F30 and others had changed them to F25. When I asked what the parameters used were (ie height of rollback assumption, power remaining, wind strength used at 500’ and airfield etc etc) there were no concrete answers.
Please see my postings above with regards to Boeing’s best achievement and p140 in the final report for F30.
At this stage I am also unaware if the original testing by line pilots (who claim to have got to the runway) involved had the knowledge of losing engines at 720’ agl or 430’ agl. To re-iterate; 720’ was when the first rollback occurred, and 430’ was when we noticed that we had power problems. I would find it hard to see how a line pilot would have managed to reach the runway if the test pilots couldn’t if they started proceedings at 430ft. Therefore I am not saying that those who have achieved the runway, didn’t, simply that if they did, at what height were they aware they had a problem and the parameters used?



SFLY
“Retracting flaps from 30 to 25 improves the aircraft L/D "global" configuration, but you still need to fly the right speed to get the best of this new configuration. Flying best L/D speed at flaps 30 will take you further than flying minimum speed with flaps 25.
The report clearly demonstrate that it was better than doing nothing, but it sadly fails to show what would have been the benefits of controlling the airspeed.”



Not sure what you’re trying to get at here SFLY…para 1, you state that flying at best L/D speed F30 will get you further than min speed F25. Para 2, you state it was better than doing nothing. Again, Boeing didn’t get within 51m of BA38 F25 ‘hanging on the stall’ speed, when they tried F30 ‘best L/D’ speed, min speed or Vref speed or any other speed, standing on their head or in boxer shorts(!), they did everything in their power to test every permutation. Therefore I appreciate you are thinking that there could have been a better outcome if it had been flown in whatever way you are suggesting, but there isn’t, if there was the test pilots would have got it.

Yes, I’m disappointed too, that there are no graphs/figures to show the distances and performance achieved at differing configs and speeds. All we know is;
F25 min manoeuvre speed = threshold – 330m.
F30 (at varying speeds) = threshold – 381m at best.
I know where I’d rather have impacted, no deaths, no fire.
SFLY... No matter how many figures and theories you want to come up with; you must accept that the manufacturers who produce all those figures, have not come up with any better results. It’s now time you believe the facts presented to you and stop getting fired up before you give yourself an ulcer. :rolleyes:



ROG747

“The procedure called for the thrust levers to be set to idle for 30 seconds,
after which each engine thrust lever is moved to max thrust to ensure the restriction has cleared.

oh....
30 seconds....? erm like you have 30 seconds to wait when your are 450' AGL”

I voiced this concerm some time back on this thread … wondering what the next chap/ess would do if a rollback occurred at similar heights, now that there is a procedure to follow. I’m not aware of any min height for this procedure, so if another crew were to continue without idling for 30secs they would be guilty of not following SOPs. However, if you are still getting some thrust at that height you need ALL you can get, not throttle back. Common sense would say to ignore the SOPs in this instance, but that’s now against company policy. I’m glad I wasn’t guilty of neglecting SOPs and bringing down a £160m a/c!



Pettifogger

“Anyone baying for the CVR, forget it. The crew probably swore, said good-bye to their loved ones, before they knew they were going to make it. What do you expect?”


CVR? Not much on it! No swearing (my wife was shocked by this), no blaspheming or saying goodbye to anyone (verbal or thoughts in flight). It was obvious that there was no time for normal comms or discussions amongst the crew, so none of us wasted time verbalising anything. We just had to get on with the job in hand, smartish.

The AAIB investigator has told me (and is happy to be quoted) that had I have taken control he would have slated me for it in the report; as I should have been using my captaincy to better use by overseeing and managing the situation, which I did. He commented that because I had a competent F/O that I was right to use his experience to good use. Had I tried to take control, this would have taken vital seconds and I probably wouldn’t have had time to get my ‘hand’ in before impact.




Willie Everlearn

“The CBC here in Canada are reporting that the crew of this flight have been off duty since the accident and the Captain "is looking for work".”



For a variety of reasons I chose to accept the voluntary redundancy package offered to BA pilots in May 09 and left BA in Aug 09. Although I’ve heard yet more rumours in BA that I had been laid off, this is not true. I applied for VR and received it. I am looking for work and have found that some potential employers are not able to interview me until the final report had been released, which is fair enough. There are airlines actively recruiting on the 777 for both F/O and DEC positions (I have applications in for both positions) so I would like to think that I will be able to get an interview soon. I have another 20 years of employment ahead of me and as flying is a passion for me, I hope I will be able to spend this time flying.



MaynardGKeynes
Isn't there a fuel cutoff switch in the B777 cockpit? Is it clear beyond any doubt that the crew didn't hit the switch by mistake? Would such an event be something that the "black box" would definitely have recorded? With all the exotic explanations being offered, isn't it just possible that the investigators have overlooked the obvious? Just asking....


MaynardGKeynes
Why did it not happen earlier in the flight? To me, this is just too much of a bit of luck to have been pure happenstance. It suggests human error, possibly pilot error. But what?

MaynardGKeynes Read the report

P138 Section 2 and 2.1 This will give you all the info on the flight crew and you will see that we have been vindicated and our actions prevented a worse outcome. This was not pilot error, no matter how much it appears that you would like it to be! :ugh:

I have had to spend the last 2 years reading and hearing people, on forums, in crew rooms and on the street, pull apart my actions, claiming they were the wrong thing to do, claiming I shouldn't have done x,y,z. Some saying I froze or had chickened out as I "did not land the plane". I performed to the best of my ability and had no fatalities. I did not chose to have an accident and if I could turn the clocks back I'd have gone sick for that trip, but I can't turn the clock back and I happened to be the Captain involved. I know there have been a lot of supporters of me and my actions (even though a lot of the supporters have never met me). Sadly I also know that there have been a lot of people quick to blacken my name and also to belittle whatever decisions my wife made immediately after the crash - there are reasons behind this and unless you know them it is unfair to make such harsh criticism of her. The world is a cruel place and can deal some tough hands sometimes, but don't kick an innocent man when he's been proven to be innocent!

Do people not realise that wild accusations can affect a person's career? If I have learnt anything from this it is that before making a public comment, I should think about what implication my words may mean to another. I have been privy to some of the report for a long time now and have had to keep my silence when reading some posts. To be involved in such a high profile incident is not something I would wish on anyone.

Please, the report is now final. My actions have been shown to have improved the situation, therefore, on the day I behaved as well as any airline could have hoped one of their pilots to act. I was proud to be trained and to have worked at BA and now hope that I will be proud to work for another airline. If the AAIB can vindicate me then maybe now the negative comments directed toward me from some can halt. The report is now finalised and I look forward to getting on with my life. ;)

[TopBunk]

Pete

Very well said.

Your participation on this thread has been restrained and highly commendable.

I, along with many of your ex-colleagues at BA, wish you the VERY best for the future.

I hope that the publication of the final AAIB report, which fully vindicates the actions of you, John and Connor on the day can finally bring some closure to this for you especially.

I sincerely hope that the near future will see you with your just rewards and that a suitable position for someone of your experience! and integrity will be shortly forthcoming.

All the best :D:D:D:D:D:D:D:D:D:D:D

PM inbound.

[chris weston]

Mmmayday,

I would be very happy to fly as SLF with you at the sharp end anytime, any place.

The very best of luck with your applications. :ok:

Them as can do. Them as likely can't, make sly comments ........... errrr sorry, dyslexia creeping in.


CW

[Knackered Nigel]

The outcome couldn't have been much better given the lack of power. No fatalities!!

The pilots have been vindicated by the report, for once pilot error can be ruled out.

Pete, here's to you getting another flying job soon. :ok:

Most of the people on here giving their twopenneth have the benefit of thinking over (or over-thinking) the event from a cosy armchair and unlimited time.

I imagine Sully is getting a similar dissection on his thread.... enough already!:ugh:

[woodpecker]

If the AAIB can vindicate me then maybe now the negative comments directed toward me from some can halt.

Lets hope so!

Pete, thanks for the e-mail a while back, we both wish you good luck for the future...

Bermuda seems so long ago..

R&VG

[BarbiesBoyfriend]

Bet you'd have given your right arm for 10 Kts.:ok:

[DC-ATE]

Mmmayday38 -

Thank you for your reply. Some very good comments indeed. I am sorry if any remarks I wrote seemed to be critical of your actions that day. My remarks merely stated that _I_ didn't think raising the flaps would produce the desired results. All the tests in the sims will NEVER really prove whether it did or not. And, like I also stated, the outcome was successful no matter what action was taken. THAT is the main concern.

I guess the next obvious question is were you terminated by BA, and if so, why, or did you elect to leave on your own? Perhaps it's all too personal?

I wish you well in the future.

[PETTIFOGGER]

Mmmayday38
CVR? Not much on it! No swearing (my wife was shocked by this), no blaspheming or saying goodbye to anyone (verbal or thoughts in flight). It was obvious that there was no time for normal comms or discussions amongst the crew, so none of us wasted time verbalising anything. We just had to get on with the job in hand, smartish.My apologies for suggesting that you might have sworn.. It would have been an entirely reasonable thing to do, in my view. No slur was intended. And apologies to your wife too. Oh, and well done!
rgds pf

[captplaystation]

DC-ATE

Er, I think f you read what he wrote just above, the answer to that is plainly stated, as it was some time ago.

[L337]

DC-ATE

Just for you:

For a variety of reasons I chose to accept the voluntary redundancy package offered to BA pilots in May 08 and left BA in Aug 08

[Mmmayday38]

DC-ATE

I guess the next obvious question is were you terminated by BA, and if so, why, or did you elect to leave on your own? Perhaps it's all too personal?


For various reasons I chose to apply to take voluntary redundancy when BA were asking for applicants. I received the VR and left Aug 09. I was not terminated. I have managers there who are happy to give me references.


PETTIFOGGER

My apologies for suggesting that you might have sworn.. It would have been an entirely reasonable thing to do, in my view. No slur was intended. And apologies to your wife too.


Sometimes these forums can be like trying to text message people ... you can't read the tone in which they are sent! No apologies needed as no offence had been taken, one of the first things my wife asked was "what expletive did I use"! She is scouse so can swear like the best of them! In fact I was surprised I didn't swear and can remember telling the AAIB investigator that I was sorry if I had sworn on the CVR! :oh:

[DC-ATE]

OK.....Mmmayday38 (http://www.pprune.org/members/293139-mmmayday38).....[and others].....I'm sorry I missed that in previous posts. I still wish you well.

[TopBunk]

Just a minor point of correction on Pete's behalf, he did of course mean that he left BA in August 2009 and not 2008.

[Mmmayday38]

Ooops thanks TopBunk, you are correct I did in fact leave in Aug 09! Year change edits made. :}

[Seabiscuit]

Pete, it was always a pleasure flying with you.
Believe me your actions on that day will forever speak louder than any words you can add here. You don't have to explain yourself to the armchair experts here who have had the wonderful benefit of hindsight, the fact that 153 people can still get up in the morning, buy a coffee and enjoy life says it all.

Was just talking about the great job you did in the bar in Philli last night. (Yep im snowed in....which incidentally was the place i last bumped into you back in Dec08!)
Wish you all the best in the years to come
Seabiscuit. (also a PB)

[iwalkedaway]

Mmmayday - may I join the more than well justified chorus of approval for your actions that unfortunate day? Delighted to see you and your fellow crew members so thoroughly vindicated, and very best wishes for your job seeking. Here's to a thoroughly satisfying - and safe - 20 more years in your profession.

:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D

But having said that, could you do me a favour? Unless there were 76 two-legged people and one unidexter on board, you saved 153 SOULS that day, not 'soles'....and all within half a minute, coo!

(And yes, OK, when airborne I admit I really would prefer a skipper who can fly to one who can spell)

iwalkedaway

[moonburn]

PB
The 'faithful' always knew that you'd aced it.
Very gratifying to see it published as fact though, you and your crew can feel justifiably proud of yourselves. I hope that we will now hear deafening silence from the armchair experts. Sincerely hope that you will all be able to get on with your lives now and enjoy them. Congratulations and well done.
MB

[PoloJamie]

Pete,
I hope now with the publication of the final report that you can move on with your life and get back doing the job you love. I certainly wouldn't want to have been in your shoes and can appreciate how hard the last two years has been for you. Don't let the b*****ds grind you down. Good luck with the job applications! :-)
Cheers,
Jamie

[p51guy]

I retired with over 20,000 hrs and never had to deal with your situation. You did a great job and if it had happened to me wish I could have done as well. You did everything right.

[PJ2]

Mmmayday;

First class post - likely the finest on PPRuNe, in the best tradition of helping fellow aviators learn. I understand a recent presentation went extremely well and now I know why, having read your comments. To you and your First Officers, sir, well done.

PJ2

[TIMA9X]

For me I am so glad that you took the time to write so much good stuff on this thread always knowing more than you could reveal at the time. I can tell you that after I read the report and saw the video interview there were some quiet but cheerful celebrations with my pilot friends here in Thailand.
Many, including myself have supported you all along, I just wished the English Press did a "Sully" for you but for some reason people choose to write about the "what ifs" or "I know better" in some cases. Pete its been a long and hard thread for many of your supporters, and probably yourself but we never shied away from what we believed to be right.
I too wish you 20 more years doing what you love best!

Tima9x

[whirlwind]

I haven't followed this thread fully, but add my congratulations to mmmayday. I watched your BBC news interview the night before last and was very impressed. Well done.

[ben38uk]

PB - As an ex-colleague and also an Aug '09 VR leaver, I am simply in awe of you and your crew's professionalism and ability. Having had a relatively minor mayday incident in 2006, I know what it is like to have your every decision picked away at - but that was only in private and not in such a public fashion,

All the best wishes for the future,

:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D

[grizzled]

Pete,

From your actions on that day, to your strength of character in those long days since, right through to your latest posts here; in all instances you have displayed the qualities that come from years of experience and training, professional diligence, and personal integrity.

I salute you.
And I mean that in the highest sense and tradition of the phrase -- to express my utmost respect and admiration.

grizz

[elgnin]

I am sure that had everyone on this forum been in the same room had mmmayday's reply been read out (rather than posted on here), you could have heard a pin drop for several seconds at the end.....just before huge and lengthy applause and standing ovation.

There have been many nasty, spiteful and hurtful posts on this thread aimed at mmmayday and his crew, particularly in the last few days following the publication of the AAIB report. No point stating who, we all know who they are.

Many of those comments remained based on the posters opinion and not the content of the report - to much of a bother to read it (and for some understand it) thoroughly? Further, many of those same posters clearly do not understand the remit of AAIB.

For the main man involved in this incident to come on such a public forum is nearly as brave as the actions he took in getting 038 on the ground as he did. Even then he has responded to some of the harshest posters in a calm measured way (no spite in his tone) one by one. So perhaps now they will all wind their respective necks in and shut up.

Whilst this forum is here for people to pass opinion, much on this thread has at best been un-necessary and at worst pure ignorance.

Now that the report is published and you can move on, good luck in securing a new position on the flight deck mmmayday, I for one, sincerely hope that should I ever be unfortunate enough to be on board an aircraft in trouble, I have you up front and not one of your many detractors one here!

[Bergerie1]

Many years ago I was involved in a rather nasty incident. We got most things right, but also some things wrong, and survived. I found the things said afterwards in the crew room and in bars down the route by various armchair critics extremely hurtful.

When suddenly faced with a situation for which there has been no training you have to think very quickly and you can't always be right. The whole crew of BA038 reacted magnificently. I wonder how many of us could have done as well.

I also salute you, Pete, we have never met, but you have had my sympathy and admiration throughout this ordeal.

And to the many PPRuNe armchair experts - some of you should think twice before saying some of the things that have been placed on this thread.

[Tmbstory]

Mmayday38:

Well done to you and the Crew, I would like to add a comment from one of my previous posts that is pertinent to your incident.
" A crew is expected to perform to the best of their ability when a problem occurs, either known or unknown. In the unknown case the crew have to attempt to control the aircraft flight path, so that they have time to solve the problem ".

You have been there and have returned to pass on the knowledge learnt. Congratulations.

Tmb

[BoeingMEL]

At last, we have numerous posts quite rightly expressing respect, recognition and appreciation. As a long-time supporter of PB I have been repeatedly shocked and disgusted by many of the armchair "experts" who (ab)used this forum to air their basesless, fact-free, irrelevant, inappropriate and unjust opinions.

Blue skies ahead now Pete. Good Luck!:ok:

[Burger Thing]

@SLFY:

Not sure if you are interpreting this graph correctly. When I look at your graph I would get the impression that when I compare two approach configurations, let's say Flaps 35 and 25, then you see that at VREF the CL for Flaps 25 is around 1.4 ish and the one for F35 is maybe 1.55 while the L/D ratio decreases from almost 10.8 down to 7.8. Seems like a lot more drag to me...

During the good-ol' days hauling the 737-200s around, I remember that on a medium-heavy landing weight, the required fuel flow on approach for Flaps 40 was around 3500 lbs/h per engine compared to around 3000 lbs/h by using Flaps 30. The difference in VREF was only 3 knots. Just an example... (Sorry, I forgot about the EPR, use the fuel flow as an indicator how much Thrust is required to overcome drag :E )

And like Mmmayday38 pointed out in his good post earlier:

“The action of reducing the flap setting was prompt and resulted in a reduction of the aerodynamic drag, with minimal effect on the aircraft stall speed; it moved the point of initial ground contact about 50m towards the runway threshold. Had the flaps remained at flap 30, the touchdown would have been just before the ILS antenna, but still within the airfield boundary. The effects of contact with the ILS antenna are unknown but such contact would probably have led to more substantial structural damage to the aircraft.”

I think that sums it up rather nicely :}

I say, well done Mmmayday38! :ok:

[DERG]

Does anyone like me think I should email RR and Boeing a simple schematic of a domestic electric emersion heater? I am sure this basic concept can be applied to 70 tonnes of aviation fuel in 2010....ya think?

Yup thanks for spelling correction. I want a happy ending here..any ideas how the fuel temp can be kept up? microwave? ultrasound? fuel lines wrapped in resistance wire?

[BoeingMEL]

...cos there's no such thing. IMMERSION maybe? :confused:

[S.F.L.Y]

As Boeing couldn’t produce a better result; I would say perhaps;
Leave A/P engaged until hearing the “Airspeed Low” warning. Thus maintaining G/S. Then reduce the flaps.
This worked.Deliberately going to airspeed low warning to improve gliding distance? I'd be surprised if Boeing would produce any recommendation in that direction...

From my understanding of the report this was only a consequence of the fact that the AP remained connected (on the contrary of what the PF wanted), thus being an inadvertent and non deliberate situation. If your PF was distracted enough not to realize the AP was engaged then I'm not sure that his primary goal was to bring such an heavy aircraft down to stall speed while still over 150 ft.

I don't agree with you when you say that since there couldn't be better results, there is no need to discuss about it. I anyway congratulate you for your action on the flaps which made the difference that day. Nothing to say about your PNF role but there's still something in the report which remains unclear and certainly not satisfactory:

The report is very confusing when saying the PF intended to disconnect the AP at 600 ft, then that he believed it was disconnected and finally that he omitted to do it because of some distraction until the stick shaker activates below 200 ft. I'm very curious to understand what could be distracting the PF, preventing him to control the aircraft for several hundred feet during an emergency situation, which is basically his primary and unique task.

If the PF didn't realize that the AP was engaged while he thought it wasn't, it means the aircraft wasn't under control, which I don't consider satisfactory and I'm quite puzzled that nothing is being said about that.

Could you please take some time to clarify what is the meaning of "omission" in the report? Were you aware that the AP was engaged? Were you aware that your PF thought it wasn't? That's why cockpit communication is important, thus interest in the CVR transcription.

[CATIIIBnoDH]

Dear Mmmayday38,

My flying days are over (+15k hrs) and I was so fortunate never to experience
an accident you encountered. Not even on the sim, we did train engine failures on final but never loss of thrust of all engines on final.

We never met, maybe we heard our voices over the Atlantic or the Desert. But I want to tell you I can only hope that if I had encountered the same situation I would react in the same way you and your crew did. Chapeau for you and your crew.
Wishing you a joyful and safe career ahead.

Frank.

[cats_five]

Am so, so glad to hear that 1) the AAIB report backed up retracting the flap, and 2) no better result from that position has been got in the simulator - suspect a great many far worse results were obtained.

My fingers are firmly crossed that no-one else will have their experience in anything - hopefully the lessons have been learnt etc.

I'm not sure I would call the flight crew heros (after all they had no choice in being there!) but they are certainly professionals of the first order and worth of our highest praise for that, and their quick and correct actions in a situation that in retrospect must have been very, very scary.

Best wishes to them in their future careers.

[TIMA9X]

S.F.L.Y
I don't agree with you when you say that since there couldn't be better results, there is no need to discuss about it. I anyway congratulate you for your action on the flaps which made the difference that day. Nothing to say about your PNF role but there's still something in the report which remains unclear and certainly not satisfactory:

Can't you just leave it for a while.......words fail me!:ugh:

Can anyone smarter than I answer S.F.L.Y ?

[S.F.L.Y]

Can't you just leave it for a while.......words fail me!:ugh:Then just explain me who was aware of who was actually controlling the aircraft since the PF though the AP was disconnected while it wasn't.

A "smart" person should understand why I'm curious about it.

[nojwod]

Then just explain me who was aware of who was actually controlling the aircraft since the PF though the AP was disconnected while it wasn't.

A "smart" person should understand why I'm curious about it.

SFLY

I cannot for the life of me understand why you think it matters so much. It's as though you have this scenario in your head that you'd have been more capable and thought through the dilemmas facing this crew with incredible Swiss watch precision, constantly monitoring every switch and display in the cockpit, fully aware of the exact drag coefficient at any point after the loss of thrust, and able to scientifically compute the best configuration and angle, all the while mentally preparing for your rightful hero's welcome after you had miraculously guided the aircraft into a textbook greaser right on the numbers.

As others have said, nothing is to be gained by your rather strange terrier-like determination to continue with pointless questions and surmises, best you retire safe in the knowledge that you know best. We won't mind. Honest.

[captplaystation]

S.F.L.Y

Which part of p1ss off don't you understand. ? :ugh:

TIMA9X, sorry mate not smarter than you, just a bit less tactful. :suspect:

[BarbiesBoyfriend]

Come on chaps. No need to be rude.

There's a couple things here.

1. Well done raising that flap! Inspired and I'm sure we all hope (wish) to have the presence of mind to do the same. Top flying!:ok:

Also: No one got killed! Top notch again!:ok: (and well done to the CCrew for handling what must have been a tricky evac.)

2. On the other hand, plainly they rode the thing down the ILS with the AP in! Not so hot.

And then basically wrote the thing off when it ran out of speed and mushed in with a big 'ol rate of descent.

Could I tentatively suggest that a controlled landing, wiping out the (frangible) ILS fence might have saved the a/c?

Me, don't think I'd have got the flap in, but I'd have set it down on the ground.

[S.F.L.Y]

The report let you think that nobody was aware of who/what was controlling the aircraft between 600 and 175 ft.

Can't I ask for clarifications without being insulted?

[p51guy]

Works for me.

[Wod]

Coming in late here.

The report says they done good.

So good that they flew a near perfect descent and approach profile with no throttle adjustments.

Enroute temperatures were outside historic experience.

I accept the report.

[wiggy]

Could I tentatively suggest that a controlled landing, wiping out the (frangible) ILS fence might have saved the a/c?

Are you really saying you're willing to bet on the frangibility of the ILS "fence" in order to save the aircraft? Because if it doesn't "frange" :ooh: quickly enough it's may well be entering the Flight Deck.....


Edited to add: If you look at the 27L undershoot, either in real life or even on Google Earth, you'll see that the boundary fence is not far short of the ILS installation (the 09R Loc aerials)...now if you reckon you've got the skills to hop a gliding 777 over the fence ( which from memory is supported 2-3 metre high concrete posts) and then duck down and land it through the ILS installation, all in order to save the airframe, well, I'm extremely impressed.


Anyhow the crew were handed a load of **** at v. short notice, kudos for doing what they did.

[PETTIFOGGER]

SFLYThe report is very confusing when saying the PF intended to disconnect the AP at 600 ft, then that he believed it was disconnected and finally that he omitted to do it because of some distraction until the stick shaker activates below 200 ft. I'm very curious to understand what could be distracting the PF, preventing him to control the aircraft for several hundred feet during an emergency situation, which is basically his primary and unique task.The "some sort of distraction" to which you refer was quite obviously the double roll-back. See pages 139 to 141 of the AAIB report. Which parts of the report do you find confusing?
If the PF didn't realize that the AP was engaged while he thought it wasn't, it means the aircraft wasn't under control, which I don't consider satisfactory and I'm quite puzzled that nothing is being said about that.Something has been said about it - p 139 of the report "However, as the aircraft descended through 600 ft he became aware of a problem with the engines, indicated by a split in the thrust lever positions. It is likely that, in attempting to understand the sudden and unprecedented problem with which he was presented he was distracted and thus omitted to disconnect the autopilot as this point.”
This is also appears at point 15 in the section on 'Conclusions', p.167.

the meaning of "omission" please give a page reference for this.

[captplaystation]

Ken (its shorter ;) ) AAIB report appears to disagree with your damage assessment and suggests that hitting the ILS would not have been a good thing.
I appreciate you accepting that you may not have thought to raise the flaps, but hey, did you ever think, like many of us have done perhaps inwardly, that there also exists the possibility we would just have gone blank and sat there till the impact. I think the F/O may just have done that up to a point, but do you think any of us can appreciate his feeling of numbed disbelief that he was now piloting a glider whilst hoping that miraculously power might be restored before ground contact. Yes the A/P may not have optimised the glide performance by slavishly, as it was programmed to do, following the G/P BUT it flew the aircraft safely up until stick shaker, at which point the F/O took control and managed the best landing he could. Perhaps this could be run through a sim for session after session for months and indeed someone could come out with a different ? better? who knows ? outcome . . BUT, anyone playing this game is really not worthy of response as they are losing sight of the VERY big picture. . . . this being, that these guys were handed a totally untrained for emergency at a very late stage of an approach and managed to improvise enough to effect an arrival in a clear area that everyone, bar the poor bloke with the gear in his leg, managed to walk away from.
It is so easy to sit & pick holes in it with the benefit of hindsight, time, and a desk in front of you.
Once again I would suggest that everyone who has some lingering doubt here, listen again to the ATC tape & just try to imagine how quickly this unfolded between the calm readback of the landing clearance and the truncated mayday call followed by the ATC tx that they had crashed.
I know some will remain unconvinced, but really, with this little imagination what the hell do they know, and are they even worth responding to, for the rest of us, please guys, get real and try and imagine yourself in these guys shoes. If you can, & you are still convinced you would have done better, I suggest you need to either sober up or take a reality check.
Having been exonerated of any misdemeanour, indeed even praised in the report, I cannot imagine why some (and I am thinking particularly S.F.L.Y ) wish to (or even feel they have some expertise or right to ) subject him to trial by PPRuNe, this is laughable guys.
No-one can say how they would have reacted, no-one can say a better outcome could have been found, and yet still some want to continue with " what if, & how, & why didn't ,etc etc.
This is beyond ridiculous now.
These guys were handed @ 720 ft a glider, they realised this @ 480 ft and 35 seconds later put the aircraft in a place & in a fashion that enabled everyone to survive.
Which part of the BIG picture is it that you should not be in admiration of, that results in this spastic attempt to chew on the minutae of what you "would" :rolleyes: have done better.

Big reality check required for some posters.

[jumbojet]

We fly the same routes, but I didnt fly that day. My collegue did though, as others. They were behind 038, but in a 744. Its true OATs were at a very low level, so low that many twins were asking for lower levels. Indeed in the 744 the Low Fuel Temp illuminated, so speed was increased to try & increase the fuel temp. He increase to .88, but to no avail!! Eventually he & other 744s were also all asking for decent, but amongst this chaos a lone voice was heard asking for further climb, BA038. The sarcastic conversation on the flt deck followed along the lines of "he a brave boy" No more was said & subject dropped, Until that is, the TV was turned on in the hotel!!
I have cross checked with other crews in the vacinity, they agree with the facts.
Food for thought.

[S.F.L.Y]

The report says that:
The PF intended to disconnect the AP at 600 ft.
He was distracted and omitted to do so (AP remained non-intentionally connected)
He believed it was disconnected (not aware that it was until stick shaker)My understanding is that:
Keeping the AP was not intentional
The PF wasn't aware that he wasn't actually controlling the aircraft between 600 and 175 ft (what about the PNF?)Wasn't there a crew awareness problem between 600 and 175 ft with nobody knowing who/what was actually controlling the aircraft for almost one minute?

[bughunta]

S.L.F.Y.

AKA...;)
Tireless Rebutter (http://redwing.hutman.net/~mreed/warriorshtm/tirelessrebutter.htm)

[TIMA9X]

by nojwod in reply to S.F.L.Y
I don't agree with you when you say that since there couldn't be better results, there is no need to discuss about it. I anyway congratulate you for your action on the flaps which made the difference that day. Nothing to say about your PNF role but there's still something in the report which remains unclear and certainly not satisfactory:Probably the words I was looking for, on the previous couple of pages pilots were congratulating The flight crew of BA 038, it has been a long and sometimes bewildering thread, we have been through all scenarios on countless posts.
S.F.L.Y. if you feel insulted well I am sorry, but it may be possible that it was a badly timed post.

Captain Burkhill has been through a lot since the incident, and I am sure that many current pilots felt some relief for him since the report came out. We are all human so I ask you to watch the BBC video again BBC News - Hero BA pilot speaks of Heathrow Boeing 777 crash (http://news.bbc.co.uk/2/hi/uk_news/8505163.stm) (already posted on this thread but for your convenience,) trust that you may see what I and others are on about. To say anything else of a technical nature would have already been said on this thread other than to leave you with one question. Don't you think the BA038 crew deserve some credit/congratulations for the outcome of this incident moreover the relief that Peter, his crew and families must be feeling today!
Think about it S.F.L.Y. your timing of your posts is sometimes out of order with the general flow of the thread.

Captplaystation, you said it all, sorry I missed it as I was writing this post, congrats!

[Just wondering]

Dear CPS - absolutely spot on !!

I've had a few engine failures in my time, a depress, an evac, a bunch of RTOs etc but the thing which gave me the only fright I've ever had in an airliner was the airpeed tape on my screen going u/s (plus all the airspeed warnings) just before rotate on a dark, rainy night ...... it was the lack of time to deal with it which made my heart race.

I think people forget it takes time to understand what the problem is from all the indicators, warnings etc that are assaulting your senses before you can decide and act.... or not as the case may be - good airmanship sometimes dicates that you should not make a drama out of a crisis by pushing and pulling the wrong stuff.

...... I still fly ULH and I can tell you now I'm as sharp as a beachball after a 12-16 hour flight starting at 11pm - so to have to deal with a situation like this having been awake for 20-24 hours !!!!! ..... I can only think that many of the detractors/aerodynamic PHD holders have never done back of the clock stuff and have never had to deal with a major emergency made worse by having only seconds available.

I only pray that if something this bad ever happened to me that I could match the performance of Captain Burkill and his crew. Double engine failure seconds before landing and nobody dies ...... unbelievable result !!!

[captplaystation]

S.F.L.Y

You are determined to squeeze every last drop from this favourite lemon aren't you.

Perhaps he intended to disconnect @ 600' but on realising there were other problems, decided against it & let the A/P fly whilst he tried to figure out what was happening.
Rightly or wrongly, he probably wished to fly the G/P , and indeed probably expected the engines or A/T to recover, thereby enabling him to do so whilst maintaining or regaining airspeed.
The lack of available thrust meant that the decision to remain on the glide resulted in a loss of speed. Whilst he may have (or not you seem to be assuming) been aware of this, the only remedy was to duck under the glide. It appears he didn't want to. The stick shaker prompted him to take control and in doing so he also disconnected the autopilot, which he may or may not have been too worried about being engaged, as it was probably doing what he wanted, maintaining the glide path.
As a previous poster stated, the feel of the controls on this aircraft would not make it possible to believe "you " were flying the aircraft whilst the A/P was still engaged.
Do you seriously think that his feel for the controls had suddenly downgraded to your level of comprehension of this whole 35sec scenario, and that he couldn't feel for himself that the A/P was still engaged ?
If the aircraft was following the flightpath desired by the crew, and there was insufficient thrust available to maintain the speed, do you accept that in the short time available perhaps they prioritised making the clear area , and accepted whatever speed above stall speed this gave them ?

I know you think that this was putting priorities in the wrong order, however " the proof of the cake is in the eating" and their priorities on that day seemed to have served them well.
Which part of your personality / character makes it impossible for you to realise that as a professional pilot body we seem to be broadly agreed that your fixation on two points here (the failure to fly best L/D & the delay in disconnecting, or according to you, failure to realise status of, the A/P ) is somewhat blinding you to the big picture.

You are an army of 1 here, that fact alone should be ringing some alarms bells somewhere in your head, where Oh where is YOUR situational awareness ? wedged between your buttocks I would hazard. :=

[Love_joy]

The argument about "who was flying the plane" is madness.

The FO was pilot flying having 'taken control' off the back of a monitored approach. He intended to disconnect the AP at approx 600ft, but due to the obvious distractions he didn't, or believed that he had.

Either way, the aircraft was flying as he expected it to (except the distinct lack of power). If he was manipulating the controls, or trimming, the AP would have dropped out anyway - but as its flight path was essentially as desired, it doesn't matter.

All pilots know that aircraft don't have to be flown hands on, AP connected or not.

[SK8TRBOI]

TIMA9X, I concur. I was admitedly enjoying the "back and forth" in everyone trying to deal with "he-who-shall-not-be-named"s inane posts, when I too clicked that BBC link and watched the interview.

That did it for me - it quickly refoucused my thoughts on the stark "unknowns" the crew was faced with in those 35 short seconds. The courage, skill and professionalism of Captain Burkill is palpable on that interview.

Bravo to the two gents up front. Period.

NEW: I only now realized that CA PB himself was posting earlier!

Captain Burkill - again, Bravo. I'm quite speechless at the moment...I guess the only thing I can think to say is: if my own family are ever aboard a flight when an emergency such as you encountered that day occurs, I hope and pray that you and your FO would be the two up-front and flying.

All the best to you in the future, Sir.

[DERG]

Hi jumbojet

Your pal increased speed to decimal 88 to increase the fuel temps?

This works because the higher engine oil temp transfers to the fuel mass via a heat exchanger? Of course he had four engines as opposed to two.

So in your company SOP you have a plan to address low fuel temps en route?

Now it seems to me that if instructions were to SAVE FUEL from BA operations I can see another possible factor in the failure.

[Just wondering]

A PM from SFLY "Sorry if my question is annoying you but I think it would be quite interesting to know why nobody was aware of who actually controlled the aircraft for almost one minute, at the most crucial moment of this emergency.Is there anything wrong with that?There was obvioulsy a problem of crew communication."


Taking the discussion to a P.M. You are obviously obsessed by your issues.

You've certainly never been in a time constrained emergency. You are definately not an experienced aviator. "If" you are a pilot then I hope you don't find out the answers to your questions the hard way - you will probably find out something about yourself very quickly.

In my loss of airspeed incident - communication between me and my co captain was at a bare minimum ..... I had to instantly deal with, after I got over the surprise, an emergency that I had never seen before. If you don't understand the process of recognition, data gathering, communication, decision and action in these circumstances then what can I say - 35 seconds - go for it superman !!

[Shaka Zulu]

DERG you are talking absolute arse.

[captplaystation]

Just wondering,

Don't worry I have had two as well, wondering why he can't ask the same question repeatedly for two weeks without us all being nasty and rude to him.
In between this thread, and the Turkish airlines thread where he spends his time unable to comprehend the difference between the two accidents, er S.F.L.Y. these guys had no power, the other guys didn't use it . . . . and the Concorde thread where his main target seems to be BA, he is unable to understand that we are a bit fed up to respond repeatedly to his same assertions day after day, whilst no-one actually agrees with them. Tedious doesn't even begin to describe it. :ugh:
He fails to understand the difference (or is it similarity? :hmm: ) between being thick-skinned and simply thick.

No experience, and even worse, no imagination or humility, to even allow him to begin to imagine how those 35secs must have felt.

Waste of space/energy. :oh:

[DERG]

Hiya Shaka

I use BS..better than the word you used.

Well unless I have missed a fundamental fact about this planets atmosphere... I believe that the higher you go the colder it gets..yes? no?

As you go lower the air gets denser..yes? no?

I may be mistaken...Please entlighten me!

[captplaystation]

DERG
I may be becoming senile, but wasn't it all about increasing skin temperature i.e. TAT, to increase the fuel temp ? well if my memory serves me it is on a 737 anyhow, rather than as a function of increased power/heat exchanger.
The difference in power required to maintain the higher speed will be minimal, the difference in temp I would suspect not be enough, but maybe tangible. This is obviously more viable at lower altitudes where you have a somewhat larger window of airspeed available to increase to, shurely not the case here on a long flight.
Anyway, Shirley, if everyone else was descending, either there was a problem with the fuel temp measuring on MMM or everyone else was in a different bit of air, as I seem to remember the report stated the fuel temp remained within limits for the duration of the flight.

jumbojet, did any of your colleagues note the fuel temperature they experienced and whether it differed greatly with the FDR readings in the report pertaining to the accident aircraft. Perhaps a tech problem that is being missed.

[Mmmayday38]

SFLY

Just need to tell you that I'm in the middle of the school run at the moment; but will respond to this later on, as soon as I can.

[Shaka Zulu]

DERG,

First off, the atmosphere does not always follow a linear path in temperature.
I have seen it quite a couple times where climbing actually increases the SAT (static air temp). A lot of the time it has to do with troposphere/pause/stratosphere.

Secondly, yes increasing the oil temperature helps warming the fuel however flying faster increases the TAT (total air temperature) due to more skin friction. This increase of temperature can be in the order of 4/5C. Depending on how much you can accelerate of course.

Thirdly, the number of engines is completely irrelevant.

Fourth, we do not get instructions from BA Ops to ''save fuel''.
Best practice dictates that if fuel temperature does not look like it's going to be a problem then why not climb if it saves fuel?
Plus we are largely second guessing to why BA038 climbed. It could well have been that their Mach No was restricted on the few airways that connect Europe to the Far East.
Hence climbing and increasing the Mach No might have been more beneficial then sitting ''low and slow''.
At any rate it's complete guesswork.

As long as the low fuel temp warning (3deg typically of Fuel Freeze Temp) does not illuminate and the forward flight plan has been asessed for OAT's then climbing ''should'' have absolutely no impact whatsoever.

[MATELO]

Just need to tell you that I'm in the middle of the school run at the moment; but will respond to this later on, as soon as I can.

TBH, I wouldnt bother. Just ignore them with the contempt they deserve.

[horsebadorties]

If you had bothered to read the whole report instead of jumping to the conclusions (in both senses of that...), you might have found the following:

Assessment of flight crew actions - summary
From the available evidence, it is apparent that the flight crew’s preparation and conduct of the flight preceding the engine rollbacks was orderly, and in accordance with the operating company’s standard operating procedures.

On the final approach to land the flight crew were presented with an operational situation, a double-engine rollback at a low height, which was unprecedented. Most importantly at this point, when the stick shaker was alerting them to an impending stall, they kept the aircraft flying and under control so that, at impact, it was wings level and at a moderate pitch attitude. The reduction in flap setting did allow the aircraft to clear the ILS aerial array and, given more height, it would have been more effective.

In analysing the flight crew’s actions during final approach, the first indication of a problem was the thrust lever split. The flight crew did not, at this time, realise that this was associated with the ensuing engine rollback; slight splits in the thrust lever positions are common and manually moving the thrust levers back into alignment is a normal response. The flight crew became fully aware of the problem some 30 seconds before touchdown and at this point the subsequent high rate of descent at impact was inevitable.

The crew’s attention was on monitoring the approach and the external environment and, while the autopilot remained engaged, the crew’s focus was on the developing situation with falling engine thrust and reducing airspeed, and their subsequent attempts to restore power.

In the very limited time available after identification of the problem, the flight crew clearly prioritised their actions and thus did make the ‘MAYDAY’ call, although they were not able to make the ‘brace brace’ call. The initial use of the VHF radio rather than PA system for the cabin evacuation call had no effect on the accident outcome


It is on P140 in case you are interestd.

[Flightmech]

Mmmayday38,
I wouldn't bother entertaining him either:( NO pilot involved in an incident/accident is REQUIRED to come on here and answer questions. That's what official reports are for. However, thousands are grateful to you for coming on here and sharing your experience.:D

[TIMA9X]

Mmmayday38
Agree 100% Flightmech, Peter has done so much to explain things never with a hint of malice.
To Quote Captplaystation:
You are an army of 1 hereI am afraid SFLY you need to understand that two or three pages ago everyone was praising Peter Birkill & crew, all of them well known current pilots and you come along and the whole thread went back to the "what if's" or "I know better" which has besieged this thread from day one.

If Mmmayday38 does respond, will you accept what he has to say then leave it alone for a while? SFLY my understanding of the words "good result" seem to differ from yours. BA038 ended up a great result considering all the circumstances in those 50 seconds or so the crew had to handle!!! Who cares about when the AP was switched off, you have to agree with the principle that a pilot with a lot of hours under his belt on a triple 7 knows the the feel of the AC!

This has been discussed over and over again. Someone said "humanity" please also keep this word in mind, pilots are not machines with AP switches implanted.

[Baron rouge]

Here we have all those captains prising the skill and luck of BA 038 crew for saving all those lives and it is perfectly understandable as in civil aviation the first thing you are told is :
"In case of emergency engage the AP if you can, or leave it engaged because it flies better than you!!!!"
No surprise then , they kept the AP ON., and the co-pilot, PF, was trying to understand what the f.. was going on instead of FLYING the A/C in short finals….

You can say what ever you want guys, but so close to the ground, the only job of the PF in a dire emergency is TO FLY the A/C.

And if you think, I do not know what I am talking about, I landed a Mystere IV after a flame out in short finals and a Jaguar on the undershoot after a bird strike again in short finals… all I did then was flying the A/C .

The PNF did his part retracting the flaps, the PF did not Fly the A/C.

[EBMissfit]

Phil Golin
"It is amazingly obvious that they did/do not want to mention the actual water content of the fuel on the flight. It SEEMS to be mention only three times and almost only in passing at "35 - 40" ppm, HOWEVER, all the tests were run with concentrations of 90 ppm (or more). There is no examination in detail of the actual measured water levels or what the actual state of the fuel/water mixture might have been like at the landing stage."


1) 35-40ppm is what was left in the fuel after landing - in other words that does not include water which may have settled and been recirculated by the water scavenging pumps.

2) The estimates for water concentration at loading are (admitedly up to) 40ppm dissolved and 30ppm entrained - or up to 70ppm. To get from 70-ppm at the start to 40ppm at the end, the concentration of water in the fuel leaving the tanks needs to be higher than 70ppm. If you read the bit on water scavenge system, you will see that the low lying fuel (more likely to have higher concentrations of water) is re-injected near to the pump inlets - why, because you are trying to get rid of the water or it will just settle back to the bottom - the way out is through the engine.

3) "A target water concentration of 90 ppm (as defined in ARP 1401) was selected for all the tests." SAE-ARP 1401 being the international standards publication for "Aircraft Fuel System and Component Icing Test".

Its not a glaring gap - its not precise, but then again as they have stated, very little about reproducing this is precise, their testing was to prove the viability of their hypothosis, because it was basically a new hypthosis.

[phil gollin]

EB Missfit

If you look back (if it is possible) at the previous two "mega-threads" covering this accident, you would see that we have covered the water content of the fuel (both in conjunction with the interim reports and from other info) and it is the LACK of any of all this previous info being repeated/summarised in the final report which is so amazing.

The choice of a standard BUT NON-REPRESENTATIVE 90 ppm for any initial tests might have been a sensible starting point. However, the tests failed to get consistent failures even with the unrepresentative 90 ppm. There is no mention in the final report of any attempts at testing at more representative water/fuel levels, nor IF any such tests were performed of any results.

It is not possible to regard the tests quoted in the final report as significant to the actual flight conditions. That is the glaring problem with the report. The report did not (at the least) repeat/summarise the information in the interim reports about the actual and presumed water levels in the flight at the time of the accident. It did not explain why tests actually representative of the presumed water/fuel levels weren't undertaken. The report has taken inconsistent results from unrepresentative water/fuel mixtures and somehow stated that they show the probable cause.

"Their" tests did not consistently prove "their hypothesis" (as you put it) - there were only occassions when they managed it. So what did the tests actually acheive ?

And, as ever, I would add the there does not, so far at least, seem to be a major industry wide investigation into the "new" phenonmen, nor an examination of ALL engine/airframe combinations to see if other designs may be at risk.

.

[PETTIFOGGER]

SFLY
The report says that:
The PF intended to disconnect the AP at 600 ft.
He was distracted and omitted to do so (AP remained non-intentionally connected)
He believed it was disconnected (not aware that it was until stick shaker)I do not speak for the crew but ~
What you have written above is an interpretation of the AAIB report which is almost accurate, but not quite. I prefer to keep to the exact text of the report and its conclusions, neither adding to nor subtracting from it. For ease of reference, I should like to quote 6 of the conclusions from the AAIB report which seem to be the most relevant to your concerns.

Conclusion 15. “The co-pilot intended to disconnect the auto pilot at 600 ft but became distracted by the engine rollback, so the autopilot remained engaged.

16.The loss of engine power led to a reduction in airspeed as the autopilot attempted to follow the ILS glideslope, leading to a nose-high pitch attitude.

17. Thirty-four seconds before touchdown the flight crew became concerned about the reduction in airspeed below the target approach speed and attempted manually to increase engine thrust to compensate; there was no response from the engines.

18. At 240 ft agl the commander retracted the flap from FLAP 30 to FLAP 25 which increased the distance to touchdown by about 50 metres; if left at FLAP 30 the touchdown would have still been within the airfield boundary.

19. At 200 ft agl the stick shaker activated and as a touchdown short of the runway was inevitable the commander transmitted a ‘MAYDAY’ call three seconds before touchdown.

20. At the operation of the stick shaker, the co-pilot pushed forward on the control column and the autopilot disconnected."

There is a subtle but important difference between these 6 AAIB conclusions and your three. In my opinion, they allow more insight of the causal processes of this accident as it developed than do yours. One could argue that the delay in disconnecting the autopilot was a consequence of the engine rollback, which began at 720 ft agl but only became known to the crew at 430 agl. Even then, they cannot have been sure that they would not get the power back. There is no big red flag that pops out and says ‘sorry chaps, that’s it for today.’ So it was entirely reasonable to continue to follow the ILS glidescope, whether assisted by the autopilot or not. There is no suggestion in the report that the PF was not monitoring the approach with hands on the yoke.
SFLY My understanding is that:
Keeping the AP was not intentional
The PF wasn't aware that he wasn't actually controlling the aircraft between 600 and 175 ft (what about the PNF?)Wasn't there a crew awareness problem between 600 and 175 ft with nobody knowing who/what was actually controlling the aircraft for almost one minute?
Your first point above is answered by Conclusion 15.
Concerning your second point, I choose to believe that he was aware that he was in control because he would have had his hands on the yoke if he thought he had disconnected the AP. The fact that he had not disconnected it is irrelevant because any firm input leads to immediate disconnection, as happened at 200 ft agl. This answer also covers your third question.

[suninmyeyes]

Jumbo jet

You wrote

They were behind 038, but in a 744. Its true OATs were at a very low level, so low that many twins were asking for lower levels. Indeed in the 744 the Low Fuel Temp illuminated, so speed was increased to try & increase the fuel temp. He increase to .88, but to no avail!! Eventually he & other 744s were also all asking for decent, but amongst this chaos a lone voice was heard asking for further climb, BA038. The sarcastic conversation on the flt deck followed along the lines of "he a brave boy"

The 777 has a different shaped wing to the 747-400 and cold fuel temperatures are not normally a problem. Although the 777 may have been flying higher than the 747-400s it is likely that it's fuel tank temperatures were warmer than what the 747-400s were experiencing.

The 038s fuel temp never got colder than minus 34 degrees with a fuel freeze point of minus 47 degrees. Obviously the 747-400s if they had to increase speed had considerably colder fuel.

As for S.F.L.Y. I get the feeling that if I or the other pilots on this forum were driving and our car went into a skid we would react instinctively. I suspect S.F.L.Y. would start thinking about theories and friction coefficients and what would be the best solution to his predicament. Too late.

I suspect that the stress and trauma experienced by the 038 crew in being involved in an accident that was not their fault is probably less than the trauma of having nearly two years of armchair experts pontificating on how they should have handled the situation better.

Best of luck Pete. I tried your scenario on the sim, absolutely horrendous feeling running out of height and speed and that is while knowing you are in a sim and cannot die. We did it a few times, could not make the runway either.

When's the book coming out?