777 Heathrow crash
 

Anyone want to guess what happened here?

777 Heathrow crash

Reports of failure to respond to autothrottle with plenty of fuel????

Gremlins?
http://upload.wikimedia.org/wikipedi...ling_hare2.jpg

Good discussion of this on Slashdot:
http://it.slashdot.org/it/08/01/20/1430224.shtml

FWIW.

Best,

Kurt

edit: Possible causes: 1) software failure; 2) fuel delivery system; 3) fuel (refueled in China); 4) human error; 5) ???? Apparently both engines failed to respond to computer and human input.

That's some pretty good piloting.

Well they have all FDR's and CVR's, we'll find soon enough. Sounds weird if both FADEC's would quit at same time. Fuel problem would usually make engines flame out, but not at same time. As far as I understood, these two kept milling but didn't want to spool up?

I bet on the software problem (probably something high up in the chain). FBW is trippled and running on embedded systems...unlikely?

What happends with ETOPS if they find FBW guilty?

I am tipping fuel. Ran out of.

What this, "it refuelled in China". Whats the significance of that?

Fuel leaked out when it crashed, according to first rapports. Fortunately, main gears didn't puncture the tanks so no fire. Also, engines feed trought different pumps and ofte, different tanks. They don't "stop respondin" simultaniously but flame out independently accompanied by lot's of warning bells and lights.

Same with contaminated fuel...unlikely that they would both just quit or stop responding at the same time if fuel was bad.

No bird impacts on engines either...maybe water in fuel freezed in feed pipes prior to feed transfered to central tank and it just coincided with landning?

Or freek "throttle lever sender sensor snapped" thing?

http://www.aaib.dft.gov.uk/latest_news/accident__heathrow_17_january_2008___initial_repor t.cfm

" A significant amount of fuel leaked from the aircraft but there was no fire." ...
"Initial indications from the interviews and Flight Recorder analyses show the flight and approach to have progressed normally until the aircraft was established on late finals for Runway 27L. At approximately 600 ft and 2 miles from touch down, the Autothrottle demanded an increase in thrust from the two engines but the engines did not respond. Following further demands for increased thrust from the Autothrottle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond. The aircraft speed reduced and the aircraft descended onto the grass short of the paved runway surface.

The investigation is now focussed on more detailed analysis of the Flight Recorder information, collecting further recorded information from various system modules and examining the range of aircraft systems that could influence engine operation."

P.S. Do BA 777 fly polar route between LHR and Bejing? Middle of winter + polar route + water in fuel + fuel transfer =? Sound unlikely though, aren't engine feed tanks on the B777 outboard of the engines?

I still bet on SW/Autoland/FBW problem...

Problem for 777 ETOPS cert?

Top notch flying. Sounds as if they nailed the centerline, if not the runway.

We'll be sending a survey team over shortly, I'm sure. We are all assuming it will be to confirm it is a write-off for the insurance company. Then again, no one has written off a 777 yet, and no one wants to be the first. BA may be willing to spend up to the cost of new to fix this one. There are no open slots in the firing order for a few years, and they really need that airplane. Looking at that quartering left rear photo, though, with the walking beam torn loose and sticking out like that - I think she's done. I'll be in Cardiff in a couple of weeks on a 767 SIP tech assist for BA; I'm sure we will be talking about it then...

Jeff,

Great info. Any insights on the 787 delays, barrel mismatches, fasteners etc? I read on another blog that people working the line are advocating using airframe #1 for destructive testing instead of another one down the line since #1 is proving so troublesome.

For an idea of the complexity and the redundancy of the fuel system in the big planes, here is a basic diagram of a 737 fuel system. I don't think any single clogged line could cause the problem, and doubt fuel ice was an issue. Each tank has 2 feed pumps, and you can fuel either engine from any tank.

I would think it was a software problem, since neither engine responded.

http://www.b737.org.uk/schemefuel.gif

dude, fill in some some acronyms

• FDR's, -- Flight Data Recorder
• CVR's, -- Cockpit Voice Recorder
• FADEC's -- Full Authority Digital Engine Control ??
• FBW -- ???
• ETOPS -- Engines Turn Or Passengers Swim??

ETOPS Engines Turning Or Passengers Swim! :D :D :D
FDR
CVR
FADEC
FBW

There are a lot of other 'nicknames' for this one, but it really does mean FlyByWire.

Most of the nicknames start with 'fing' or 'French'

i'm sure opinions will vary widely on this subject, but when i flew professionally many of us were fond of saying 'friends don't let friends fly by wire..' :D

i'd hate to think i was screwed by a bad cb or 'bad wire'..i'd rather be the 'hero story' of the pilot who lost all hydraulic flight control assist and had to 'muscle' the plane down.. ;)

Nothing I can share here. And remember, anything you might be reading on any blog is no better than unsubstantiated rumor, based on second or third hand information at best. Everybody knows somebody who has a cousin whose brother-in-law works on... fill in the blank. Or my personal favorites, the "unamed sources" or "speaking on the condition of anomymity..." No more than internet busy-bodies; the modern equivelent of a bunch of cackling old hens.

bock-bock-bock

I'm gonna guess FADEC (Engine/fuel computer) or Auto-Throttle inputs. I think something (or someone) "told" the engines to shut off. By "told" I mean either by failure of a computer (which with redundancy is hard to believe with both engines at once) or an input commanded a spooldown. One thing for sure is pilots around the world are very interested in what happened, probably as much as Boeing is.