Me Myself

Not in a life time !! The aircraft just bled its energy so fast. Getting to the end of the runway was really fantastic.
You have to try to imagine the magnitude of such an event. As someone put very accuratly on the site earlier, no one knows what he would do in such a case. Trying to get the grip of what's happening and to think of a way to remedy ot it in a such a short period of time is hard to imagine.
I'm glad I had a chance to try it on the sim, it does give you an idea of what the unthinkable is about.

golfyankeesierra

and it ends with:

..........

PAXboy

I understand, Me Myself that the elapsed time from loss of power to impact was 50 seconds +/-. Could you verify that from your SIM session?

pattern_is_full

The "update" is a final report on a June '06 Nott. East Midlands Boeing 737-300 accident/incident - but to be fair the AAIB website has a screwy revolving link, so if you click at the wrong instant, you something different than you intended. And it does say "5/2008 Update" - just updating on the wrong subject....

Likely what happened to Sky9

Me Myself

Afraid not and if it was, even in the sim, it did feel very very short. Bear in mind this is just something we did at the end of recurent training because we had 10 minutes to spare. No rocket science. We just wanted to get the feel of what these guys must have experienced. We started at 4 dme, configured full flaps and retarded the engine one after the other to end up almost precisely at the same spot. Didn't change flaps setting because we didn't think of it too busy flying, but then, no fence in the sim.
Again, caught in the real thing I really don't know what my reaction would have been and I just hope they would have been along Cpt Burkill's lines.
Any sensible pilot will think the same way.

All of us flying the 777 would really like Boeing to come up with some explanations so it can be fixed and allow us to relax a bit.

Bearcat

I have asked it again and again , what is the envoirnment envelope re temps for a 777? In the 320 it is SAT -70.

I note when they checked the fuel freeze temps at the accident site, they were -57c.

They had loads of juice coming into land (10 tons), fuel must have been like jelly for some reason....hmmmm.

Xeque

Me Myself - I can well understand how you guys feel.

A question from someone whose regular steed is a C150. The report states that the autopilot disengaged at 175 agl when the speed had decayed to 108 knots. Is it normal to keep the autopilot engaged so late in the approach? Or were they exercising a Cat 3 autoland where (I guess) the autopilot stays engaged.

The report seems to pretty well squash any thoughts of fuel contamination, freezing etc. Also, it seems to indicate that there was nothing wrong with the fuel delivery system apart from the mention of cavitation damage.

What's left? Way back in this thread I (tongue in cheek) said 'Windows fatal error'. Is this what its going to turn out to be - the old 'blue screen of death'? Dilbert on a bad day?

wilyflier

Bearcat
OAT +8 or +10.Like jelly or like froth? or both?

Mariner9

The freeze point of the fuel may well have been -57C when tested, but if a kerosene is cooled to wax precipitation, wax drops out and is not redissolved into the fuel, then the freeze point of the Kero will be lower after the event. In other words the freeze point of the fuel would have been above -57C prior to wax precipitation, if it had occured.

However, if that were the case with BA038, the question arises what happened to the wax and why were no traces found? (I presume the investigation has included GC analysis of the bulk fuel and residual fuel on the filters for comparitive paraffin component profiling)

L337

Xeque: BA fly a monitored approach. It was the FOs sector, so the Captain flew the approach for him. The FO took control at 750'. Now normally what would happen, the FO (in this instance) would have disconnected the autopilot, and continued to do a manual landing. What follows is conjecture, but it is a fair bet to say that, as the AT failed to respond, and the situation unfolded. Both pilots would have looked inside and gone "WTF". Best decision was, I would hazard to leave the autopilot in and try and work out what the hell was going on. During this small window a decision was made to retract the flap one stage. That saved the day. As the speed decayed the A/P disconnected, and they hit the ground.

Would hand flying a "fly by wire" aeroplane helped in these circumstances? No idea. Those who have tried it in the sim would suggest that they made the best of what they were presented with.

It is important to remember that they first had to notice the problem. Then they had to diagnose it, then they had decide what to do. All close to the ground in circumstances they would never have seen before, and never have been trained for. That they made the crucial decision to retract the flap that saved the day cannot be under emphasised.

What I do know is that, God forbid, If I am ever presented with something so unusual in such a parlous position, I can find it within me to do as well as those guys did.

/respect

Oluf Husted

Dear fellow PPRuNers,

Since the BA38 crew, unknowingly, flew a: "Green Approach" (idle) with the engine anti-ice system in "Auto" they probably had some core engine icing, that caused the hesitation.

That must scare, all involved in a B777 flight (app. 1000 times a day) with an average of 200 seats sold, equals 200.000 human beings and some in the leadership of BA, RR, AAIB and Boeing, sh..less.

That why, the AAIB did't find any signs of ice damage, it just melted away.


Oluf Husted

davecr

Nice bit of shameless self promotion there Oluf......

Thank you, also, for pointing out what "Engine anti-ice" is, as many of the airline professionals and the AAIB would OBVIOUSLY not have a clue as to what causes it or how to look for traces of it after an accident!

Just because you can't find any ice in the engine doesn't mean you can't establish an icing condition using collected data!

"that caused the hesitation" - there was no hestitation, the engine was completely unresponsive and continued running at idle until impact.

obie2

PAXboy wants to know if the time from 4DME to touchdown equates to 50 secs, or there abouts. No one seems to want to tell him!

Assuming 180 kts average over 4nm= 80 secs.

Adjust the average, adjust the time...simple!

borghha

dear Oluf,

I read your anti-ice plea 'for your grandmother to understand' and found it not only very amusing but very interesting indeed. (I am a frequent SLF, and being an interpreter, was able to read your text in danish)
However, your analysis refers only to stator/rotor blade ice formation while taxiing and the way to get rid of it prior to TO and after landing. So if I understand you correctly, what you call 'the hesitation' of BA 038' engines could have been caused by ice debris, but can what happened to this flight (engines throttling down to somewhere above flight idle and staying there) be described as mere 'hesitation'? or do you think there wasn t enough time for the engines to resume normal operation? and how would this relate to the cavitation found in the HP pumps?

and, following from your theory, no 'green approach for you in certain weather conditions?

Fly safely.

Me Myself

Surely you're joking right ?? Unknowingly ??? This approach has been going on since basically .........the ice age !! I find myself repeating " Roger, 160 kt til 4 DME " in my sleep.
Since you are coming from 210 kt down to 180 kt and requested to keep 160 kt til 4, this is basically a green approach.
I suggest that, like the rest of us, you wait for the final report instead you make any phony assumptions.

davecr

PS Oluf, how often do you fly 160kts IAS fully conifgured at idle thrust?

Oluf Husted

Dear davecr,

According to the AAIB report, page 2, from feb. 2008 (latest): "The Engines initially responded but, at a hight of about 72o ft, the thrust of the right engine reduced. Some seven seconds later, the trust reduced on the left engine to the same level"

That is "Hesitation" in my book.

The different Jet Engine Producers, Airbus & Boeing and The Airlines has over the last 50 years been "Out of Synch" about recommendations and actual Anti-ice and De-ice Procedures.

And not until 1994, it was never admitted that, at idle power, the anti-ice systems does not work.

Oluf Husted

Oluf Husted

Dear davecr,

Anytime I had speed to "bleed of" but at 1ooo ft, (or at the very latest) 500 ft, pilots have to be "stabilized" and so it seems to be with the BA38 crew.

Oluf

davecr

Dear Oluf,

As I too aim to be stable at 500' on a daily basis, I am well aware of this

It seems to be a language problem here, as you seemed to suggest that the aircraft was idle all the way down to being at its "stable" criteria. Furthermore, our interpretation of the word "hesitation" seems to differ slightly.....

Nevertheless, I think you are out of order to be speculating about the cause of this accident, especially using the words that you did. Excuse me for having more trust in the AAIB then an engine icing enthusiast.

Can I also point out that this type of approach is not carried out unknowingly, but is highly encouraged due to fuel savings and noise restrictions in this part of the World? As mentioned before, min 160kts until 4DME or somewhere along those lines is the standard at London airports.

Dave

Oluf Husted

Dear borghha,

Right, no (fully computerized) "Green Approach" to me, but a late descent and a less than idle power setting when the anti-ice systems "on" is OK!

It is also valid, when airborne, what i wrote about run-ups during taxi "out" and "in. You need MORE than idle power, to get hot air enough, to keep the metal/platinium in the front end of a jet engine above freezing point.

So, my guess is, that the BA38 flew at idle power from FL400 to 720 ft, and even if the selected anti-ice "On" it does not work at idle, even if it should according to certifications.

Oluf