Jump to content
Join the Unexplained Mysteries community today! It's free and setting up an account only takes a moment.
- Sign In or Create Account -
Lottie

Airliner Crash Lands at Heathrow Airport

104 posts in this topic

Recommended Posts

questionmark
You said there are no electronics involved however it seems that it is all electronics unless in an emergency the pilot chooses to "go outside the control envelope". Can you link me to something where it says the manual override reverts to cable/pulleys as it seems that would add an awful lot more complexity/weight/lack of reliability etc. and defeat the whole point of going down the fly-by-wire route in the first place. It would be more sensible to have redundant electronic circuits for manual control.

That is the Airbus way... but Boeing could not do that after polemizing about the lack of security after Airbus introduced fly by wire in commercial aircraft. But even in Airbuses there is still a mechanical override in case of emergency.

Share this post


Link to post
Share on other sites
keithisco
From what I have read about this accident and this plane for both engines to refuse power at the same time it MUST have been a command from somewhere, I just wonder where ?

eidt: it had two Trent 895 engines, manufactured by Rolls-Royce.

Not according to wiki:

http://en.wikipedia.org/wiki/Boeing_777

Absolutely correct MM. The 895 is a derivative of the RB211 powerplants (FROM THE 747). they have an electronic interface. This gives scope to look back at my original comment that the engines were not at fault but possibly the Command Control software that allowed both engines to "not-resond".

I am seriously leading to software problems now, even not having any hard evidence from the flight recorders to go on.

Share this post


Link to post
Share on other sites
Moon Monkey

If it is absolutely impossible to access the reference input from outside the loop then it leads back to software/data presentation glitches like those seen in that the Australian flight 'close-call'.

http://www.atsb.gov.au/publications/invest...0503722_001.pdf

Edited by Moon Monkey

Share this post


Link to post
Share on other sites
keithisco
That is the Airbus way... but Boeing could not do that after polemizing about the lack of security after Airbus introduced fly by wire in commercial aircraft. But even in Airbuses there is still a mechanical override in case of emergency.

That depends on which family of aircraft you are talking about. The electrical and electronic interfaces would now receive a Lloyds 100A certificate for competence. Airbus have to complete 1,000,000 take offs and landings, completely without physical intervention to achieve FAA and EASA approval. This (IMO) is the way forward, always have a senior pilot on-board, but flying aircraft is no longer the domain of overly-rated pilots. I do not think that it will be more than 2/3 decades before fully automated aircraft will be the normal mode of transportation.

Airbus (A380) took a hit 2 years ago, due to wiring problems, but that has been resolved, and I had the honour of watching the A380 land and take off in Getafe (Spain) and I never knew it was arriving, it was that quiet....

Just my "two cents"

Share this post


Link to post
Share on other sites
questionmark
If it is absolutely impossible to access the reference input from outside the loop then it leads back to software/data presentation glitches like those seen in that the Australian flight 'close-call'.

http://www.atsb.gov.au/publications/invest...0503722_001.pdf

Pretty scary that one, especially the blocking auto brakes, you get the plane to the ground after wrestling like Hulk Hogan and then you loose your undercarriage because the wheels block... great!

Share this post


Link to post
Share on other sites
questionmark
take off in Getafe (Spain) and I never knew it was arriving, it was that quiet....

I remember that airport, I once landed on the military part by error (in the mid '70s), boy did I cause an alarm .... :cry:

Share this post


Link to post
Share on other sites
keithisco
I remember that airport, I once landed on the military part by error (in the mid '70s), boy did I cause an alarm .... :cry:

Definitely scary!!! It must have been just before, or just after General Franco's death (1975) when Spain was still a dictatorship. It is now the hub for EADS and Airbus in Spain, and is shared with the air force, no commercial traffic allowed at all. But, for security, it just makes me laugh. It's a Eurofighter (Typhoon) proving ground, the A400M is being developed there, radioactive materials are stored there, but you can just walk onto site!! :angry:

One of the other airports in Madrid (Cuatro Vientas) was sold by the Mayor here just last year without any vote being taken on the decision, guess democracy still has a long way to go

Share this post


Link to post
Share on other sites
questionmark
Definitely scary!!! It must have been just before, or just after General Franco's death (1975) when Spain was still a dictatorship. It is now the hub for EADS and Airbus in Spain, and is shared with the air force, no commercial traffic allowed at all. But, for security, it just makes me laugh. It's a Eurofighter (Typhoon) proving ground, the A400M is being developed there, radioactive materials are stored there, but you can just walk onto site!! :angry:

One of the other airports in Madrid (Cuatro Vientas) was sold by the Mayor here just last year without any vote being taken on the decision, guess democracy still has a long way to go

I was flying from LECO to Madrid VFR on a Mignet 152 (classical wood-tube-cloth) 2 seater and somehow screwed up my navigation. In those days radio was not yet mandatory and naturally I did not have one. Never saw that many guns pointed at me as that time again. Yep, scary. But as soon as the Teniente realized that it was a honest mistake he invited me to a drink, to calm my nerves. Then they got one of the pilots to show me how to get to Cuatro Vientos.

ED: it was 1973, I had just gotten my PPL and it was my first major excursion.

Edited by questionmark

Share this post


Link to post
Share on other sites
keithisco
I was flying from LECO to Madrid VFR on a Mignet 152 (classical wood-tube-cloth) 2 seater and somehow screwed up my navigation. In those days radio was not yet mandatory and naturally I did not have one. Never saw that many guns pointed at me as that time again. Yep, scary. But as soon as the Teniente realized that it was a honest mistake he invited me to a drink, to calm my nerves. Then they got one of the pilots to show me how to get to Cuatro Vientos.

ED: it was 1973, I had just gotten my PPL and it was my first major excursion.

Well,

If you ever want to re-trace that journey let me know. Be glad to show you around. There is a good collection of vintage jets on the apron at the airport. I extend that offer to Mid and Lord Umbergar as well as any other Aviators out there.

Edited by keithisco

Share this post


Link to post
Share on other sites
questionmark
Well,

If you ever want to re-trace that journey let me know. Be glad to show you around. There is a good collection of vintage jets on the apron at the airport. I extend that offer to Mid and Lord Umbergar as well as any other Aviators out there.

I would not know where to find a serviceable Mignet nowadays (smirk). But I'll take you up on the offer the next time I am in Madrid.

Share this post


Link to post
Share on other sites
Fluffybunny
I was flying from LECO to Madrid VFR on a Mignet 152 (classical wood-tube-cloth) 2 seater and somehow screwed up my navigation. In those days radio was not yet mandatory and naturally I did not have one. Never saw that many guns pointed at me as that time again. Yep, scary. But as soon as the Teniente realized that it was a honest mistake he invited me to a drink, to calm my nerves. Then they got one of the pilots to show me how to get to Cuatro Vientos.

ED: it was 1973, I had just gotten my PPL and it was my first major excursion.

That is classic...I did something nearly as stressful when I first got my ppl years ago. I learned to fly at Chino Airport, a wonderful place that is also a WWII plane museum. It is not too far from Los Angeles and you have to be careful when you head west as you can easily get into LAX airspace very quickly, and Ontario International is not very far the other direction, so flying vfr for fun in the area is a bit like running the gauntlet trying to remember what altitudes the Class B stuff is in the area, which drops up and down all over the place...there are very narrow corridors in the area until you get out away from the airports over the desert where I practiced manuevers.

anyhoo...cessna 152... inexperienced pilot...LAX approach airspace...angry voices on the radio... ughhh... The time when I wish that little plane had rocket boosters to get me the heck out of there...

I assumed I had lost my license, but I guess they never even reported it...

Share this post


Link to post
Share on other sites
questionmark
That is classic...I did something nearly as stressful when I first got my ppl years ago. I learned to fly at Chino Airport, a wonderful place that is also a WWII plane museum. It is not too far from Los Angeles and you have to be careful when you head west as you can easily get into LAX airspace very quickly, and Ontario International is not very far the other direction, so flying vfr for fun in the area is a bit like running the gauntlet trying to remember what altitudes the Class B stuff is in the area, which drops up and down all over the place...there are very narrow corridors in the area until you get out away from the airports over the desert where I practiced manuevers.

anyhoo...cessna 152... inexperienced pilot...LAX approach airspace...angry voices on the radio... ughhh... The time when I wish that little plane had rocket boosters to get me the heck out of there...

I assumed I had lost my license, but I guess they never even reported it...

ain't it fun when they guy at the ATC tries to stay polite despite wanting to use every cuss word in the book?

Share this post


Link to post
Share on other sites
Fluffybunny
ain't it fun when they guy at the ATC tries to stay polite despite wanting to use every cuss word in the book?

Oy. Most stressfull time I ever had in the air. He skipped the being polite and went straight to curt, condescending and rude; but not so bad as to read innapropriate on a transcript...He had obviously done that before...

Of course I have no idea what kind of snafu I caused as I was not tuned to LAX approach so I could have been the center of many a diversion and really thrown things off for him...

I promised myself to take up crop dusting or some other "low traffic" flying after that :)

Share this post


Link to post
Share on other sites
questionmark
I promised myself to take up crop dusting or some other "low traffic" flying after that :)

Hmmm, guess that is a career too :lol:

I quit flying in the early 80s in Germany, they hardly have any space that is not a B or C or restricted military zone. Absolutely no fun. Here on the island sometimes I wish I had kept my license current, if only to leave at any time the "island fever" hits me. But keeping a full TPL with IFR and multi engine is quite expensive.

Share this post


Link to post
Share on other sites
questionmark
Back in the late 1990's, the 'new' GMS digital mobile phones crashed servers in our computer apparatus room. However, these computers where NOT shielded against RF. I'm sure the systems on an aircraft WOULD be.

However, as a hyphothesis: if you started bombarding an aircrafts systems with EM pulses then we would expect multiple failures and error signals. This didn't happen in this case.

Meow Purr.

This cellphone crashing a computer made my dust-off my collection of old clunkers, and yes I managed to crash one, a Olivetti system 1, a so called minicomputer build in the late 70s. The reason was that the ferrite bead memory array is susceptible to radio frequency interference. No solid state computer crashed though, even the Sinclar ZX81 worked without a problem, and you can hardly call that one tempest proof.

Share this post


Link to post
Share on other sites
keithisco

Hey Guys,

thought I'd stick this picture here (courtesy of BBC). 4 engines, no ETOPS concerns :-)

post-54624-1201123802_thumb.jpg

Dont you just love Burt Rhutan!!

Share this post


Link to post
Share on other sites
Space Commander Travis
Hey Guys,

thought I'd stick this picture here (courtesy of BBC). 4 engines, no ETOPS concerns :-)

post-54624-1201123802_thumb.jpg

Dont you just love Burt Rhutan!!

How about this then?

post-18342-1201163175_thumb.jpg

Share this post


Link to post
Share on other sites
questionmark

Heathrow crash inquiry focuses on fuel supply

By David Millward, Transport Editor

Last Updated: 3:56pm GMT 24/01/2008

Investigators examining the causes of last Thursday's crash landing of a Boeing 777 at Heathrow have switched their focus to fuel supply.

The Air Accident Investigation Branch said that it would examine the "complete fuel flow path" from the aircraft tank to the engine fuel nozzles.

According to the AAIB's latest report the two engines on the 777 did not shut down, as first thought. It said that the thrust on the right engine fell – which could explain why the plane appeared to bank as it approached Heathrow.

Then eight seconds later, the thrust on the left engine also fell. Both however continued to work, but with inadequate power. Investigators have also established that the engine control commands worked normally.

Suggestions that the plane ran out of fuel have been dismissed. The aircraft was found to have an adequate supply when it was examined on the ground.

The mystery now is why the engines failed to respond despite the automatic throttle appearing to work normally. In the wake of the latest report the consensus among pilots is that the plane's difficulties could hinge on the failure of fuel to reach the engine.

Clues as to what happened on Thursday may be contained in reports of previous engine difficulties – which were disclosed by The Daily Telegraph.

Six have been logged by American safety investigators, two of which do relate to fuel problems.

Oil pump contamination was identified as the reason for an Air France 777 suffering an "uncommanded engine shutdown" on July 1 1998, which caused the plane to be diverted to Tenerife while en route from Sao Paolo to Paris.

The on June 6 2001 a Thai Airways 777 suffered a ruptured fuel tube on a flight en route from Taipei to Bangkok. The plane was diverted to Danang, Vietnam after the pilot recorded plummeting fuel levels. British Airways has 43 Boeing 777s.

A spokesman said that the airline was continuing to co-operate with the AAIB inquiry, but refused to say whether any action was being taken as a result of its initial report.

Rolls Royce, the manufacturer of the engines on the stricken 777 also declined to discuss the significance of the latest findings or what action it was taking as a result.

A spokesman said the company was co-operating with the continuing investigation.

Source: The Telegraph

---***---

So my bet is the switch-off solenoid, any takers?

Share this post


Link to post
Share on other sites
keithisco

Help me out on this....

right engine thrust reduces, so left engine increases workload to compensate, and to maintain altitude relative to the glideslope. Control surfaces actively respond to the localiser (ILS approach) 8 seconds later the left engine loses thrust... did they go into "Spooling Down Mode"? I guess thats one question, but probably not from the statement issued.

Remembering that it is twin engined, so ETOPS ( Extended-range Twin-engine Operations) 120 certification (possibly 180) applies to its construction which means that no single point of failure to both engines is allowed. So a switch - off solenoid (if you mean the engine shutdown, Airbus terminology) still doesnt seem likely, can never rule such a thing out though.

Actually this incident could have a knock-on effect in terms of its ETOPS certification if a single-point-failure mode IS discovered. If no failure can be found then that will be even worse because the correct course of action would be grounding of the fleet from the same build - until the fault is found. Lets hope they find something concrete. It's taken a long time for confidence to return to the aircraft industry.

Share this post


Link to post
Share on other sites
Fluffybunny
Actually this incident could have a knock-on effect in terms of its ETOPS certification if a single-point-failure mode IS discovered. If no failure can be found then that will be even worse because the correct course of action would be grounding of the fleet from the same build - until the fault is found. Lets hope they find something concrete. It's taken a long time for confidence to return to the aircraft industry.

That is exactly what I was thinking. It is so much better when they find a bundle of vibration frayed wires, or an obvious line of code that is the culprit. To not know, and not be able to reproduce the incident is going to be a long term grounding problem; specifically for the plane, but I think it is going to have wider impliations for fly by wire planes in general...people are going to be nervous for a very long time. It turned out as well as can be this time, but who know next time...randomness is not kind to plane investigators.

Share this post


Link to post
Share on other sites
Adam_666

wow bet that was scarey

Share this post


Link to post
Share on other sites
keithisco
That is exactly what I was thinking. It is so much better when they find a bundle of vibration frayed wires, or an obvious line of code that is the culprit. To not know, and not be able to reproduce the incident is going to be a long term grounding problem; specifically for the plane, but I think it is going to have wider impliations for fly by wire planes in general...people are going to be nervous for a very long time. It turned out as well as can be this time, but who know next time...randomness is not kind to plane investigators.

I'll put you on list with QM, and Lord U, for a trip to Getafe and see the A400M, MRTT, and their amazing collection of vintage jets. I'll PM nearer the time (if you can make it), with plans and potential dates, but no rush. It's good to ba able to talk to enthusiasts! :D

Add to that a visit to Eurocopter in Madrid, amazing chopper!!

Edited by keithisco

Share this post


Link to post
Share on other sites
chemical-licker

fuel! holy crap :o

Years of avaition and then this, sounds like a student prank, "lets pour some sugar in the tank" :hmm:

Share this post


Link to post
Share on other sites
keithisco

Latest (abridged) update courtesy of the BBC:

Link to full story: Full BBC Report

Instead the investigators specifically mention the plane's fuel system.

The Boeing 777 has three fuel tanks - one in the centre that is used up first, and one on each wing, which would have been in use during the later stages of the flight.

There are six different pumps to push the fuel to the engines. If any pump fails, fuel can be routed via an alternate.

If an engine fails the fuel can be 'balanced' between the wings to take account of the one-sided thrust, and the fact that the tank on one wing will empty faster than the other.

Fuel examination

Keeping everything working is an 'electronic engine control', part of a system called the FADEC which monitors the power needed.

This takes into account a range of variables including: the configuration of the aircraft, the condition of the outside air, the state of the engines themselves, and of course, the position of the plane's throttles.

This system knows the limitations of the engines and stops them being damaged by heat or pressure. Crucially it is supposed to work independently of the plane's autopilot, to make sure the engines function properly.

It is this collection of computers, tanks, pumps, sensors and their backups, which the investigators are examining closely.

But they will also be examining the fuel. It might have been contaminated. Or fuel "waxing" may have occurred.

This results from partial freezing, and pilots say the outside air temperature at some altitudes en route to the UK was down to minus 70 degrees that day - some of the coldest readings they could remember.

There are heating systems to bring the fuel up to the temperature required. Perhaps these failed.

Close scrutiny

The US Federal Aviation Administration has identified seven previous incidents involving Boeing 777s where ice and melting water clogged up the sensors and pressure lines of the FADEC system, preventing it from controlling the engines properly.

The biggest concern was that this could happen on both engines simultaneously, a scenario eerily similar to last week's crash.

The FAA's findings only related to General Electric GE90 aircraft engines. The pair on the British Airways Boeing were Rolls Royce engines. Maybe they suffered a similar problem

Share this post


Link to post
Share on other sites
Moon Monkey

First report is out. No evidence of mechanical failures.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.