Unfortunately, far enough.

With F30 in calm conditions, you're going to need about 1.05-1.06EPR (c.50-55%N1) to maintain a 3deg slope, fully configured at Vref30+5, at the approximate landing weight we're talking about. The engines at the time were producing 1.02-1.03EPR from the AAIB report.

Things improve a bit with F25, needing 1.03-1.04EPR (45-50%N1), so pretty close, which is why moving to F25 might have helped. If the failure had occurred when the flaps were at 20 or less, the residual thrust would have been in the ballpark for maintaining a 3deg slope, gear down. That wasn't what happened, though.

Thanks for the helpful data FullWings.

I don’t want to sound picky, but to me, looking at the graph, the engines at the time were producing more like 1.03-1.04EPR, which is a bit closer to the desirable request.
Anyway, the point is there was still some valuable produced thrust, knowing that the FF reduced only 8000 feet before the threshold, I am surprised BA38 touched down at the end of the rope a full 2000 feet before the usual touchdown point ?

In no way this is a critic to the crew, but keeping the Vref would have been a better option than keeping the Glide Slope.

As we have seen again in CIA this week, dual engine malfunction (?) in final DO happen.
It would be time to implement such exercise in sim training, not to cover all possibilities but just to make aware of different options and consequences.
As always, let’s learn from the unlucky one.

Hi CONF iture,

I took the EPR levels from page 2 of the most recent AAIB Interim Report, where it states: "...at a height of about 720ft the thrust of the right engine reduced to approximately 1.03 EPR (Engine Pressure Ratio); some seven seconds later the thrust on the left engine reduced to approximately 1.02 EPR" and further on in the same paragraph: "...The FMVs responded to this command and opened fully but with no appreciable change in the fuel flow to either engine."

An interesting hypothesis. F30 on the 777 is the most you can hang out, i.e. it is drag flap with little corresponding increase in lift compared with F25. I would put forward that Vref30+5 is, with *significant* thrust being produced, quite a bit faster than Vx in this situation. Maintaining speed at 'bug' (1.3Vs+5) with F30 would lead to intersecting the ground plane some distance short: not a real improvement on what happened. There is the possibility of some help from ground effect but a) it's not over flat terrain and b) the aircraft is in its 'dirtiest' config. and bleeding energy fast. I don't think we'll ever know for sure what the optimal course of action might have been, unless someone runs some *very* detailed computer analyses (NOT in a simulator). I have a hunch that the answer will be different for each second that goes by on the approach.

I've done total engine failures as part of conversion/recurrent training on several types, including the 777. However, the situations have been (deliberately) set up to be 'survivable', i.e. a more than evens chance of getting the thing down on the runway in one piece, given average skill levels. The BA38 (and possibly the recent RYR) were both at the edge of the envelope and to try and train for rare incidents like these would probably leave the impression that in real life you'd be lucky if you weren't dead. A bit negative, not to mention the best recovery techniques are probably peculiar to each incident, so there is little 'generic' help to take away with you...

Phil gollin, ....and something that 2 of the 3 AAIB Safety Recommendations addressed. Concerning the semantics, "theory" seems appropriate as defined by the OED. On your comment about there being insufficient water to form ice, isn't that what I said?
Rgds

Pettifogger

A "theory" which fails to have the correct circumstances for it to be valid and also which cannot be even commenced to be tested is not a valid "theory".

.

not enough water.... post 2056 Phil Golin
 

Phil to reply to your assertion about not enough water content strikes me as "denial" ,The Met physistists swore there wasnt enough water at 25000ft to cause a Viscount complete 4 engine shut down over the Alps in1958. Their figures were out by an enormous factor , something like100/1. So we had to modify all Bristol Proteus engines as a result.
Heavy ice built up in the Ubend very rapidly,then came away in a rush

Phil gollin, re your post #2066, sorry to get picky or even pettifogging about this, but according to the compact OED, a theory is a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained. 2 an idea accounting for or justifying something.
http://www.askoxford.com/concise_oed/theory?view=uk,
or if you prefer Chambers ED "an explanation or system of anything: an exposition of abstract principles: speculation as opposed to practice". (sorry, no linked source for this one)
Or the Merriam-Webster dictionary "6 a: a hypothesis assumed for the sake of argument or investigation b: an unproved assumption". This one seems particularly fitting, wouldn't you say? theory - Definition from the Merriam-Webster Online Dictionary

Sorry to be irritating and quote dictionary definitions, but "theory" as described above is what I meant to say, and it seems to me to be entirely appropriate at this stage of the investigation. If you or others think not, or disagree with some aspect of the AAIB's Interim Report and Safety Recommendations, I shall respect their views, but without seeing convincing arguments (or sources in the case of further 'definitions' of 'theory'), would be unlikely to agree with them. For the present, I prefer to stick with the AAIB's avenue of investigation, particularly the yet to be seen assessment of the fluid dynamics modelling, something which I alluded to much earlier, around post #500, I think.
rgds pf

This is a waste of time.

It is a hypothesis - as in "IF there were more water, then ......."

It cannot be a real "theory" as it doesn't have the right conditions to start with.

.

Nobody appears to have a definitive answer. That is the AAIB, Boeing, etc,etc. As has already been published the complete fuel manifolding, valves etc had been removed from one wing and reassembled into a test rig. Now (in the last week!) the complete manifolding from the other tank has been removed to make up the complete a/c assembly to see if that makes any difference to the test results.:8

@ wilyflier,

Not to be nit-picking, to my knowledge the Bristol Proteus was indeed prone to icing but was married to the Britannia, not the Viscount. The Viscount had RR Darts.


@gas path,
With regards to "the other tank", that does not mean only the other main tank but I assume that also includes the fuel lines and override jettison pumps from the center tank?


Green-dot

Yes, that should have been tanks! So the (test) rig assembly will include everything on the fuel side.:8

Venturi works for liquids too
 

Green dot post 2071
We all know the difference Viscount /Brit and Dart/Proteus but both engines were reverse (air)flow
The Viscount event was a wake up call.
My statement pointed out that the pundits figures on the water content conditions everyone accepted as normal were wildly wrong and so design changes were made across the industry.Reverse flow was avoided in new engine designs.Existing designs were modified to de- ice the bends.SOPs were issued to avoid icing conditions
It may be a bit fanciful but are we coming to the idea that liquids and gasses have similarities in flow behaviour round convoluted ducting and that ice accretion occurs in pipe lines carrying wet fuel similar to impact icing on wings and such? .New stricter parameters for dynamic fuel-icing avoidance?

wilyflier:

"We all know the difference Viscount/Brit and Dart/Proteus but both engines were reverse (air) flow".

In words of one syllable (or maybe two) - boll*cks.

The Proteus as fitted to the Britannia was indeed a reverse flow engine but the RR Dart was most certainly not.

For those of you who are unfamiliar with reverse flow turbo prop engines, here comes a simple explanation.

The only reason to have a reverse flow engine is to reduce the length of the engine and make it more compact (like the PT-6). So, the airflow enters the intake behind the prop and then goes through a 180 degree bend before entering the compressor. Then it goes through another 180 degrees before the combustion stage and then exiting through the turbine stage.

On the Britannia, the Proteus engines used to ice-up badly on the first U-bend and this caused the aircraft to be years and years late on entering service.

Even then, the problem was never satisfactorily solved. The civilian Brits had heating skins (B skins) fitted but their use caused a 10% loss in thrust. Even then, the engines were for ever shutting down and restarting (called "bumping") in icing conditions and this ensured that the crew never were allowed to go to sleep.

The RAF had a cowl heat system fitted but this resulted (so I'm told) in a 25% loss in thrust every time the system was used.

I will now move on to the RR Dart; I flew the Argosy for ten years and also the Viscount 802/806.

The Dart was a conventional engine in that there was no reversal of flow. It simply went: compression stage, combustion stage and then turbine stage. That is why the Dart was such a long and slim engine.

In fact, the engine was developed in a very simple fashion. When the Da 6 was not powerful enough, compression and turbine stages were added and so it was that the cowlings got longer right up to the Da 10.

I have never heard of four Darts failing at once through icing. I have personally had four inches of jagged ice on the engine intakes after an engine antice fault and not one of them even murmured.

I still think it Carb ice
 

Sorry about the bollocks ,Didnt the dart have a centrifugal stage whuch changed the direction of the airflow>?
As for the Viscounti icing up over Switzerland . Im not wrong about that .Caused plenty of kerfuffle at Bristol ,I was there

This page has a cross section of a Dart.

Actually I flew a Dart or two too.Twos and fours
 

Thanks Fzz, look like plenty of U bends there to me.

Dodgy Proteus U bend at inlet to compressor so cold.

Perfectly OK Dart U bends at compressor outlet so hot.

No mention of the Proteus Rabbit Warren fix yet!

Well, I suppose it is a matter of your interpretation, but I would hardly call a two-stage centrifugal compressor where the airflow moves from the front of the engine towards the rear "a reverse flow engine".

Anyway, none of this has anything to do with BA038 so I'm off out.

whattimedoweland,

Nice flight deck picture.

Does anyone happen to have a picture of the BA B777 first class cabin (four class cabin configuration), preferrably taken from the rear in the direction of flight?

Thanks,
Green-dot

What, there's something behind the first class cabin :ooh:

(and there must be a few 'matron' comments regarding that quotation too :))

PS: regarding the 777 photo, what's Capt Cheapskate going to do now he's left his Holiday Inn pen behind:confused: Let's hope he got a new pen on his IAD nightstop :}.

Looking at the graphs in the AAIB report, it would appear to me that if the crew had brought the flaps up to 20 and and accepted a speed close to the F30 bug speed (i.e the go around speed) with the remaining residual thrust there would have been a very good chance of getting the aircraft down in one piece. ( I write this as a retired 767 capt so am not familiar with the 777).
This is not a reflection on the crew of the aircraft but a suggestion for the future, has anyone tried it in the sim?

Under normal conditions, bringing the flaps up from 30 deg. to 20 deg. would take the engines out of approach idle (with thrustlevers at idle position and engine anti-ice off), reducing thrust to minimum idle.

Not sure if that factor would have influenced the circumstances on the already rollbacked engines in this accident. In other words, if it would have restricted the already limited fuel flow even more or not. Hard to tell as long as the cause of the restrictions has yet to be revealed.


Another recent rollback is under investigation:

NTSB investigates Heathrow-like Trent 800 engine issue


Green-dot

Ba 038 777 Accident Remains Unresolved
 

It may be quite important that professional pilots continue to follow this thread. Yes, the AAIB and the NTSB have published information which will probably lead to a conclusion.

It should be very important to all who seriously contribute to this network that vigilance is important.

What happened to BA038 has not been satisfactorily explained. The corrective action makes sense. Nevertheless, the entire aviation community who live at high altitudes, in cold temperatures, for extended periods of time need to follow this thread.

I trust the official investigation teams and the people who support them. I also know from almost 80 years of experience in my family that truth follows examination.

What happened to BA038 is unacceptable. Stay on this thread and contribute.

The AAIB and the NTSB, Boeing and RR are to be trusted. We are the people who make that trust valid. Keep this thread alive.

Tom

sky9

Keeping Danny in Sandwiches

Join Date: May 1999
Location: UK
Posts: 961


Looking at the graphs in the AAIB report, it would appear to me that if the crew had brought the flaps up to 20 and and accepted a speed close to the F30 bug speed (i.e the go around speed) with the remaining residual thrust there would have been a very good chance of getting the aircraft down in one piece. ( I write this as a retired 767 capt so am not familiar with the 777).
This is not a reflection on the crew of the aircraft but a suggestion for the future, has anyone tried it in the sim?
http://static.pprune.org/images/stat...er_offline.gif http://static.pprune.org/images/buttons/report.gif

Yes, you can make the runway in the sim.

Flaps 20 is half leading edge slats. Large drag reduction with small increase in approach/stall speed.

Residual thrust was greater than idle.

Slowing below Vref increases drag and decreases your glide performance.

We have 20/20 hindsight, crew had seconds to make the appropriate decisions.

Can someone please tell me, or show me the agencie's 'corrective action' recommendations?
Thanks,
Tank

Correctives
 

Some action was taken by some Carriers within 60 days, and was mostly procedural and related to fueling; one can surmise water checks, dumping and test schedules, etc.My understanding is each Line reacted individually according to SOPS and modifications to station procedures. I haven't seen hard copy, and you may not either, then again, you might. In any case, everything is on this thread, so don't ask me to direct you to it, happy reading.

(You fly 135's or sumthin else?)

AF

USA FAA Contact URL re BA038 777 Accident
 

See following URL re USA FAA action re BA038


Justia Regulation Tracker Airworthiness Directives: Boeing Model 777-200 and -300 Series Airplanes Equipped with Rolls-Royce Model RB211-TRENT 800 Series Engines, - Federal Aviation Administration - 52909?52911 [E8?21138]

Did they really determine the causes?
 

Hello!

and later :

Emphasis of mine.

Virtually identical ice release both sides, causing virtually identical fuel restrictions?

I have the feeling that they do issue an AD, for the shake of "doing something" ...

bis47
 

You are on the money. However, the FAA is doing what it does, mitigate challenges to safe flight. Any AD is almost always a compromise, based on real world factors. One could fault the Trent design and suggest swapping out that powerplant for another less sensitive to corrupted fuel.
Holy CRAP, can you imagine? The Trent isn't the problem; in this case it is merely involved in the solution.

Initially, the carriers reacted by massaging their fueling and sourcing dependencies, including emphasizing steps on the book but not being followed.

Missing from the AD, quite naturally, is the politics and economics of yiping about the true culprit. Here is where I find fault with the FAA.

"In Spec.?" A spec isn't arbitrary, but it makes compromises in the real world. "Ice in Fuel?" Not cute, but how much is too much? The triple 7 is a brilliant aircraft, the Trent, like everything RR is an exquisite engineering feat. Chinese Fuel? The Jury is still out. My 2 pence. AF

Aside: If you are still worried about how ETOPS breaks down into a "simultaneous fault", don't be, myself and others have tried to point out that a twin op ends up functioning in unity with late stage homogeneous systems. Making "identical" demands of two engines (autothrottles) operating in a wickedly similar ambient environment produces wickedly similar results, not rocket science. Sometimes, ETOPS isn't. That can't be AD'd. ETOPS solution? One Trent, one GE per a/c. Better solution? get the water out of the Fuel.

AF

"ETOPS solution? One Trent, one GE per a/c. Better solution? get the water out of the Fuel."

My solution: FOUR engines over water, period.

DC-8
 

Four engines over water, period? That's what I thought when ETOPS hit the pilot lounge, and I reacted the same way. I was made to feel like a reactionary and dinosaur. But that was also when four engines meant four hot pipes, loud flow through a single orifice. What calms my psyche when I fly twins over the Pacific these days, is that I'm flying two hyper dependable propellor engines. Basically, (very basically) ducted thrust turbo-props. I'm still a prop guy at heart, so call me old fashioned.

I'm not so sure Al wouldn't have preferred to have been flying over water when #2 exploded over Sioux City. Forced landings are exceedingly rare.

"Forced landings are exceedingly rare."

Ya.....but it only takes ONE !!!

?
 

It only takes one. For what? I've had three, all involved still breathing and still flying. The DC-10 fireball at Indiana was survived by many. It had three engines, was flying over a number of suitable asphalt runways, was not ETOPS, (E-THROPS?) and yet 180 people perished. An uncontained Turbine failure. The old arguments were mooted long, long ago. Fuel? That can be a problem anytime. Simultaneous failure? likewise. I will emphatically agree that loss of two engines in ETOPS is doodoo land. It is also a forced landing in a four engined a/c, generally. Think about it. It is certainly a forced landing in a three engined a/c. AF

"It only takes one. For what? I've had three, all involved still breathing and still flying. The DC-10 fireball at Indiana was survived by many. It had three engines, was flying over a number of suitable asphalt runways, was not ETOPS, (E-THROPS?) and yet 180 people perished. An uncontained Turbine failure."

It only takes one forced landing to ruin your day.

You've had THREE?!?! I'd be buying lottery tickets if I was you.

Are you talking about the UAL in IOWA (not Indiana)? That was kinda "close to home" (same company) so to speak.

misd-agin
I wasn't making any criticism of the crew, the incident was outside the knowledge of the crew and therefore they cannot be criticised for what they did. I was however asking if there was anything that could be learnt from the incident for the future.

Captain
 

Yes Iowa. Sorry. I think a forced landing has to do with an immediate and unavoidable landing, not whether it is survivable or not, and I don't think three of those is unusual in 40 years of flying. Without looking it up, I think it was Capt. Al Haines? Lots of help in the cockpit, and although the a/c was unflyable, people lived. The accident was powerplant related, the a/c had three engines (at least at T/O), and I think is instructive when discussing the "dangers" of ETOPS. By the way, I've always been fond of Douglas a/c, and if you fly (flew) the friendly skies, you remember my favorite, the DC-6. We may have some mutual acquaintances. AF

Yep - being lucky can make you an hero...

Again they certainly did their best but the BA public relation coup is really mind boggling :(

"Yes Iowa. Sorry. I think a forced landing has to do with an immediate and unavoidable landing, not whether it is survivable or not, and I don't think three of those is unusual in 40 years of flying. Without looking it up, I think it was Capt. Al Haines? Lots of help in the cockpit, and although the a/c was unflyable, people lived. The accident was powerplant related, the a/c had three engines (at least at T/O), and I think is instructive when discussing the "dangers" of ETOPS. By the way, I've always been fond of Douglas a/c, and if you fly (flew) the friendly skies, you remember my favorite, the DC-6. We may have some mutual acquaintances. AF"

Yes, it was Al. Are you saying HE had three forced landings, or you? I'm just thankful I never had ANY in 30 years.

Ah yes, the DC-6/7. First Type Rating. Great machine. Flew all seats. I was the last one off. I still prefer the Connie, but never got a rating in it. Probably why I liked the -8 so much; some similarities with the Connie.

Yup, we probably have some mutuals. I guess we're getting a little off course, however.

Ba 038
 

This is a pro-forma entry.

Given no futher input from AAIB, NTSB, FAA or other authorities from 14 January 2009 regarding this thread, the members continue to await further science and knowledge.

The BA038 accident remains a serious and unacceptable situation. It is hoped the interim action required by the AD note eliminates the possibility for further issues.

Nevertheless, unresolved causes for accidents and appropriate final correcctive action must be the primary focus of this thread.