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-   -   BA038 (B777) Thread (https://www.pprune.org/rumours-news/340666-ba038-b777-thread.html)

WojtekSz 11th January 2010 20:26

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 11th January 2010 21:19


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 12th January 2010 10:50


..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 13th January 2010 13:00


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 13th January 2010 14:27

Airbus type Logic ?
 
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 13th January 2010 15:02

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 13th January 2010 15:19

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 13th January 2010 18:48

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 13th January 2010 21:38

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 17th January 2010 08:55

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 17th January 2010 09:56

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 17th January 2010 12:33

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 17th January 2010 13:13

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 17th January 2010 13:58


Originally Posted by SelfLoadingFreight-Yup
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 and 1005 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 17th January 2010 14:15

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 17th January 2010 21:37

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 17th January 2010 21:57

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 17th January 2010 22:00

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

bubbers44 18th January 2010 18:41

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 18th January 2010 20:27

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).


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