Heathrow 777 crash flattens servers Yesterday's crash-landing of a BA Boeing 777 at Heathrow had the unfortunate knock-on effect of flattening the servers of the Professional Pilots Rumour Network (PPRuNe). This morning, the site was showing the following message: PPRuNe Servers vs Exceptionaly High Number of Visitors Whilst this may be a sore point for many …
"*Spare us the "so why did you publish the link?" whines. Even if we didn't, the first thing you lot would do is Google the PPRuNe, so we've saved you the trouble."
Can we put this on Slashdot, too?
In the 'States, the NTSB at some point will release either transcripts or actual audio of the "black box." Any chance that will happen in this case?
Was Paris on-board?
Planes are pretty much run by computers now because the huge majority of plane crashes proved to be the fault of the wetware flying the plane. If you compare crash stats from the 70s to now, you can see the decline.
But as everyone on this forum knows, the hardware can fail. You can have failsafes and backups and all of that, but how many can you put on an airplane?
I have to take my hat off to the pilot. I also think an emergency override, so that the pilot could have actually operated some parts of the plane the old-fashioned way, sounds good. Would the stupid pilots panic and use the override whent he computer was doing a better job? I don't know. But good pilots shouldn't have to rely on their plane's gliding ability...
Geese are a threat to our society and we should be installing CCTV near all bodies of water in this country -- no matter what the expense, to ensure that geese can be tracked.
I propose tax money be diverted from hospitals and schools and put into projects to tag all geese, and gather all their genetic data to create a database of their full genomes and feather-prints. Geese seen to be gathering together, or in places we think they shouldn't be should be rounded up and imprisoned until it can be proved that they are planning to kill us all.
Only with a global war on geese will we finally be safe!!!!!!!
Someone doesn't need to die for it to be a crash. The plane is basically a Write-Off.
If someone wrecks your car, but you're both still alive, then that wasn't a crash was it.
A successful landing is one where the plane is in the same condition it was when it took off, and it landed on the runway is was intended to.
A Crash, as in this case, Is where the plane is smashed up, can't be used again, and did not land where intended.
The B777 must have been running Windows for Airplanes and all that was needed was to press Ctrl-Alt-Del and reboot. Unfortunately, these keys are missing from the Flight Management Computer on Boeing777,
http://img250.imageshack.us/img250/4627/b777fmccduib4.jpg
so the the pilots had to use the alternative - a fly-over-the-wires dead stick landing...
Burkill has since been praised for gliding the stricken airliner over houses and managing to belly-flop it 50 yards inside the perimeter fence ...
I have no wish to denigrate the pilot's ability (I'm a commercial pilot here in Australia) but he wouldn't have been able to put the aircraft down onto the houses even if he'd wanted to. And ANY, normally-stable aircraft can glide. What the pilot did was do what he's supposed to do which is follow the first rule in any emergency - FTFA (fly the flaming aircraft). Training and experience!
I'm making these comments only because I'm tired of all the media hype and hysteria (not to mention ignorance) surrouncing aviation incidents.
The problem being that reader's sense of humour seems to have suffered serious failure and shut itself off about 400mm above the keyboard, unfortunately they have not been able to glide themselves in to the correct terminal and thus missed the point entirely.
'We don't believe this was a terror related incident'
As if we are all living in constant fear of terror attacks, I think they have a little more propoganda to spout before that is the case.
Sorry I know its not mentioned but it was in the BBC's intial report, and I had to mention it because it annoys me that 'terror' seems to be the every other word on these peoples lips.
I agree that the bird angle doesn't really wash.
The fact that these 7 series beoings are soooo areodynamicaly effiecent and can glide for miles with very little power (yes they fly themselves folks) is probably what helped that pilot save hundreds of people from dying yesterday.
If indeed the plane did "shutdown" it's testment to the areodynamic economy of the wing design and the pilots ability. well done.
However these planes are DESIGED to continue flying in event of a bird strike.... yes these babys can (and regulary do) fly home on a single engine...FACT!
If it was a whole flock of geese taking out ALL of the engines.... well thats just unlucky!
"Planes are pretty much run by computers now because the huge majority of plane crashes proved to be the fault of the wetware flying the plane"
Well the Beeb had a pilot on yesterday saying that 95% of landings are still biologically controlled, and the computer is there as a standby.
"Well the Beeb had a pilot on yesterday saying that 95% of landings are still biologically controlled, and the computer is there as a standby."
He was talking about auto-land but on FBW airplanes every command input goes through a computer and the latter than decides what the airplane actually does, based on the control laws. This is supposed to prevent most human errors through envelope protection - when the computer does not allow the pilot to exceed critical parameters such as minimum airspeed and maximum angle of attack.
But humans proved they still can easily outwit the computer and crash the bloody plane if they want to...
For all you people claiming that an un-powered Boeing 777 is uncontrollable go and Google "Ram Air Turbine" and educate yourselves before claiming such a broad thing.
For the lazy a Ram Air Turbine is an emergency generator that pops out the bottom of the aircraft in the event of total electrical failure, it uses the wind going past the plane to provide electricity to power the hydraulics, it isn't much but better than nothing. (and the power naturally drops off with the speed.)
Any landing you can walk away from is a good landing.
Any landing you can't take off from again is a crash landing.
There is, therefore, such a thing as a good crash landing.
And the VAST majority of aircraft today are NOT fly-by-wire; the controls are directly mechanically linked to the control surfaces. The vast majority of aircraft are also not commercial aircraft.
Hilton, because she knows about direct mechanical linkages.
quick thought here for all those saying loss of power means he has no control over the fly by wire plane:
assume it was a very very unlucky bird strike or similar that took out all the engines, why would this instantly mean that the computers on board would fail? Loss of power means loss of engine power, not electrical power,
you really think those things are up there without batteries and UPS's?
>>> Would the stupid pilots panic and use the override whent he computer was doing a better job?
I have read fatal aviation accident reports that say this has already happened. The one that comes to mind is a helicopter crash somewhere in Great Britain where city, sea, mountains, and of course clouds are all mixed together. The "visiting" pilot and the old-hand pilot (acting as co-) believed the autopilot had a tendency to cut the corners on its turns, so they manually prevented the start of the turn for some time.
Shortly after that the terrain collision warning sounded very briefly, etc..
Official reviewers' rumor was that this model autopilot did not have any such corner-cutting tendency. I have no idea where the fatal misconception originated. I suppose eventually these misconceptions would be bred out...
The pilot obviously banked the aircraft to reduce lift thus the plane dropped intentionally so it would be nearer the ground when it hit it. The auxilary power unit was deployed to provide control surface avionics hence one sees the APU exhaust flap open in the pictures. The pointed end was raisedd to reduce speed. Loss of engine power was probably because there was a fuel problem caused by problem with fuel. Great bit of flying and the pilot is a hero to avoid what could have a terrorist incident in different circumstances.
Airliners have nice gliding properties but only in what's known as the clean configuration and relatively high airspeed. The landing configuration (lots of flaps and slats, landing gear down) is just about the opposite of that and flying at minimum airspeed doesn't help. So no a 777 it's not such an excellent glider in that situation. The plane needs quite a bit of power just to maintain the glide slope. So indeed if the plane lost all power then the pilots did an excellent job of energy management - it could have ended up a lot shorter than it did.
And no planes don't typically have a lot of batteries and "UPS"s. When the power from the engine is gone it's either an APU (takes a while to start) or a ram air turbine (probably the same). So indeed it's typical for at least big parts of a plane to actually shut down at least for a moment. The important bit is that it still continues flying just as it did and it can still be controlled some way or another. And when the power is back everything restarts just about immediately and functions correctly. Hence lack of Windows presence in the aerospace industry...
Just speculating but birds ingested in both engines doesn't sound to be like the most unlikely cause for the event. Both engines shutting down at 400 feet in landing configuration and low airspeed would explain the outcome and indeed the pilots did OK (but then every pilot is kind of trained to do what they did, it's just that not everyone gets to demonstrate it and it's not something airline pilots regularly train for in the simulator, I can imagine a certain amount of pale faces and sweaty hands in the cockpit after the event).
(not a triple-seven-pilot myself but an active night-rated and almost-instrument rated private one)
True enough. Get a double engine failure & resulting loss of power and you end up in a reversionary mode with the RAT deployed and unnecessary systems shut down, including some cockpit displays. Between RAT, batteries & hydraulic accumulators you have enough control to keep the aircraft flying, and to try to deal with whatever happened.
There is also limited mechanical backup for some of the control surfaces. Exactly how much depends on the aircraft type. Airliners at least will glide by nature (if sufficient height exists they always tend to recover into a glide, assuming the airframe doesn't fail first) so you can cope with limited direct control and/or no engines.
As for fallback/override modes, these exist but are basically options for deselecting some of the control filtering. With everything active the FCS will stop you exceeding various comfort and performance parameters eg. AOA, roll rate etc. etc., sometimes known as 'carefree handling and manoeuvring' because as long as you don't hit anything you don't have to be too careful about what you do with the controls. Though some of the cargo might complain!
Switch out the FCS (press the button or if feeling brave pull circuit breakers) and you end up in direct law, at which point you effectively have direct unrestricted control of the aircraft. This feels quite good to fly as you can explore the handling which is much sharper when unfiltered; the downside is you could end up with serious problems as there's nothing to stop you doing something unrecoverable, or which might break the aircraft except your own actions at the controls.
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Re: lack of fire. The tanks would be pretty empty after the flight given the distance, though I guess the main reason for no fire would be that the landing gear ripped through the gear well as the mountings failed under stress, but this part of the wing didn't include any fuel storage as the gear well, gear support structure & main spar would have taken up all the useful space at that point. Hence no ruptured tanks, and no fire.
Also remember that near empty tanks are actually more dangerous than full ones as they tend to explode due to the fuel vapour. The 787 will have a standard-fit inerting system to prevent this, but the 777 doesn't yet have this option, and I don't think anyone has retrofitted so far.
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Whatever happened (seems like engine control/avionics failure?) it looks like they just didn't have the height or airspeed to do much about the situation, gear down late on an approach really isn't the best time to try to deal with this kind of thing. A couple of minutes earlier and an unpowered approach might have been exciting, but the glide & touchdown would have been much easier as there'd be time & margin to adjust, and very few would probably have known what had happened unless they read incident reports.
In the past, whenever there was an unexplained accident, the whole fleet of that particular aircraft would be grounded as a very valid precautionary measure. But that wouldn't be something Boeing would be happy about ..... or their Airline customers. Although maybe they have rethought that financial inconvenience?
Sorry to continue my boring pedantic rant but there are actually two actual qualified pilots aboard every 777. One of them is the pilot-in-command (PIC) of the aircraft and the other one is not. One is the pilot flying (PF) and the other is the pilot not flying (PNF). The two distinctions are independent so 50% of the time it's not the "captain" (pilot-in-command) flying (or pushing the buttons of the autopilot) but the "co-pilot" and indeed the "captain" is just assisting (reading checklists and selecting flaps etc as commanded by the PF). And when something goes wrong and the PIC is the PNF then typically it makes sense for him to stay that way and instead concentrate on solving the problem and let the less experienced but equally skilled guy next to him keep controls. So still nothing unusual there.
One thing to keep in mind is that total loss of power (if that indeed was the case here) in landing configuration at 400 ft is just one of the things that the plane is sort of not really designed for. It's a bit like total power loss immediately after take-off - lots of effort goes into making that a very unlikely event but if it does happen anyway then it takes a lot of luck to avoid a disaster. You're not in total control anymore in a way, you can obviously turn the potential disaster into a certainty by doing something wrong but you're not guaranteed to be able to prevent it anymore no matter what you do. Not that you'll ever stop trying though. That's just the way things are for aircraft. Every pilot knows that and hence there's always that special moment when you're cleared for take-off and think once more if you really want to open the trottle or if you should just taxi back to the terminal and go and have a cup of coffee or something instead.
I worked as Flight Line Avionics Tech for Boeing Experimental Flight Test on the first few 777’s. About 16 months. Known as WA001 and WA002. It IS fly by wire but the elevator has a wire / cable backup.
The engines are Rolls, GE or Pratt’s they are similar but different. They have onboard FADEC type controls right on each engine. You could say they are fly by wire. If they loose signal from the auto flight systems and or the throttle quadrate transmitters in the isle stand of the cockpit they should go to FLIGHT IDLE which I was told would keep the aircraft airborne, especially close in with flaps extended.
I can tell you for a fact Boeing went to the 9’s on all the wiring for the fly by wire.
In case of catastrophic failure, each of the three Flight Control Computers has just beneath them there own UPS, if you will. They will maintain electrical power and control, but for a short time only, basically just the time needed to deploy the
RAT or Ram Air Turbine. This deploys automatically from the belly, it is a blade or prop arrangement connected to a drive unit that ‘Pops down into the air stream and turns like a mini wind mill generating power. This will supply emergency power electrical and hydraulic. I was working the aircraft in Flight Test when Boeing flew out and turned of all the power on the aircraft and flew it on ONLY RAT power.
Boeing tests more extensively than anyone else. A777 was tested to the point of destruction across the street from flight test, the so called Iron Bird. They pulled the wings off, not a cheap thing to do at 140 million a copy.
The questions I have are? Why was control lost to the engine throttles, if that is what happened. Did they go to flight idle? If so why did the aircraft glide path continue to be to steep? And how and did the RAT perform? You can thank God for the result of this incident as I do. I have flown many hours aboard the 777. But consider thanking the airlines commitment to good employees and their training and of course Boeing and their stubborn relentless flight test programs.
Stop me if I'm wrong, but I believe the poster a ways up the page may have been paraphrasing the legendary Chuck Yeager of X-1 sound-barrier-breaking fame.
Anyway, though... the wife and I do a fair amount of flying -- that is, riding on airplanes -- and after all that time, still, everytime we're on approach, all of my sensory cues fool me into thinking we're too low, too slow, and we're not going to make it. I'm sure that happens to a lot of folks. I wonder what those folks were thinking when it dawned on them that Holy Shit/e, we're _really_ not going to make it.
I'm especially impressed that the pilot was able to glide it in, as I was always under the impression that an aircraft that size had about as much "glide" as a set of car keys.
To those speculating about the power being lost; the 777 has an APU (Auxiliary Power Unit) which is like a third engine that runs to power a generator. This is enough to allow the rest of electrical systems on the aircraft to function normally without the power generation from the main engines.
Obviously without engine operation the FLIGHT power would be lost, but not the electrical. Even (or especially) the fly-by-wire systems are powered even in the event of a double-engine failure.
The most famous example of a big jet coping with just emergency power and some cool flying is for me the "Gimli glider". There are a few sites about that on the web.
There are a few choice remarks in that case: "The pilots immediately searched their emergency checklist for the section on flying the aircraft with both engines inoperative, only to find that no such section existed." and "at this point, Quintal selected ... Gimli as the landing spot. ... Gimli had decommissioned one of its parallel runways, which was then being used for sports car racing. Furthermore, on this particular day the area was covered with cars and campers for 'Family Day', and a race was being run on the former runway." And later "Mechanics were sent from Winnipeg Airport; their van ran out of fuel on the way to Gimli, leaving them stranded".
There was even a reasonable TV movie about it although the tiny effects budget didn't seem to reproduce the final safe - but quite weird - landing all that well. That plane reentered service and was retired in late 2007. Its currently listed as "stored" - maybe they couldn't face breaking it up.
@Anon Cow
Umm thanks for clarifying. I don't think I was asserting that the co-pilot was any less qualified to fly the plane. However it is worthy of note that the co-pilot was flying at all in this particular situation, rather than the more experienced (by definitiion) pilot letting him continue to force-land the plane. Generally speaking, when the proverbial hits the fan, the words "I have control" usually come into play and the more experienced pilot takes over.
The last time I personally heard them was when I'd screwed up a stall turn[1] and ended up plummeting upside-down[2] through cloud[3] towards a Military Air Traffic Zone[4].
[1] Fail
[2] Fail
[3] Fail
[4] Fail
They advised me not to join the RAF after that episode.
P.S. Extraordinary number of pilots reading el Reg - is IT paying too much or what?
Penguin because it has the same flight characteristics as a powerless 777
APU start would take time. At 2 miles out you are less then a minute from the threshold - the APU will not be of much help.
Also the APU will not provide you with any more thrust, so it does not really matter in this particular case.
Interesting point about flight idle but at such a late stage on finals and taken into account the inertia of a B777 for them to return to straight and level - would it be a good idea anyway?
The plane obviously was so low on energy that it would have impacted short of the threshold no matter what. Looks like the pilot increased the AOA at the last moment to hop over the fence and the plane then stalled onto the ground. This was as best as anyone could have done.
What really comes to mind when reading this story is, an electromagnetic impulse generated either by accident (cell phone blockers or similar) or by intent, which could be done from a small van close to the touch down spot. Nonetheless congrats to the fine BA cockpit crew !
Referring to the A.C. on Flight avionic statement on flight idle. It seems that flight idle is less power than that needed to keep level flight.
From wikibooks
"The idle rating is the minimum thrust that can be used whilst the aircraft is in flight. It is largely defined by the requirement to keep the engine running, possibly supplying secondary services to the aircraft such as hydraulic and electrical power, and, especially at high altitude, to supply passenger air at a minimum pressure. The flight idle rating is important in that the lower it is, the quicker the aircraft can descend (without going into a dive). It is often determined by stability considerations such as flutter and surge margin."
So I am guessing that flight idle is what they drop the engine thrust to when they start a descent. You notice it when the engines get a whole lot quieter and shortly after that the pilot or FO announces they have started the descent.
While an ETOPS rated aircraft like a 777 can start the APU in flight (to take over generator load if an engine fails), it isn't usually running after the engines are started. Once the engines are fully up & running you don't need the electricity or bleed air from the APU so it's shut down to save on fuel & hours. (Some aircraft shut the APU down automatically after the engines are running, some don't so you have to use the switch)
The 777 electrical system allows for an engine generator to fail (each engine supports a backup generator), or for a single engine to fail (in which case you start the APU), but failure of both engines & associated generators isn't so easy to deal with, especially if the failure is simultaneous.
Given height/time you can start the APU from the batteries, but it isn't instant - like any turbine it takes time to crank, spin up and stabilise before it can be used.
This is why the RAT pops out to give you a bit of generating capacity to keep some essential systems running, with the majority shut down automatically.
In the Heathrow incident if the engines shut down instead of just going to idle then the aircraft would have had to rely on the RAT (which could be seen deployed from the fuselage) and batteries for electrical power as there was no time or opportunity for an APU start.
it's very good that there was not serious injury to those aboard or on the ground. I'm not surprised to see a number of postings here from people in the know. this is el Reg, not MySpace, eh?
Regarding the glide characteristics of jet aircraft, over the years a number of amateurs have referred to the famous F-104 Starfighter as a missile with wings. I've been close to someone in the 104 programme from way back and they assert that they never once heard that expression from a 104 pilot. What they did hear was that the 104 had "the glide ratio of an anvil strapped to a manhole cover".
Thanks to all the knowledgeable comments from pilots and test engineers. Some have reported that the flaps and droops of the 777 appear to have been in the retracted state upon impact. Would it be typical for the pilot to raise those devices in this situation? Loss of lift traded off for reduced drag and all.
My money is on empty tanks being the cause - though I'm sure it'll never come to light if it was.
There's plenty of stories of airlines being reprimanded for flying into Heathrow without enough spare fuel to stay stacked in the holding pattern long enough at busy times. This was a long-haul flight against the prevailing weather, so possibly used more fuel than expected. The fact it cut out so close to the airport makes me think that the fuel reserve was marginal, if they had been miles out they would have diverted to a closer airport.
Surely BA the British Flag Carrier wouldn't risk the safety of an aircraft due to insufficient fuel?
"On Feb. 20, a British Airways [BAB] 747 (Flight 268 en route from Los Angeles to Heathrow) diverted itself to Manchester after declaring a Mayday for being short on fuel."
http://findarticles.com/p/articles/mi_m0UBT/is_8_19/ai_n11844072
And an actual AAIB documented example...
http://www.aaib.dft.gov.uk/cms_resources/Boeing%20747-443,%20G-VROM%2007-07.pdf
More cases...
http://query.nytimes.com/gst/fullpage.html?res=9C0CEFDA143BF934A15752C0A966958260
Pictures of the wreck seem to imply the following:
- one engine was fully shut down (no blade damage after ground impact, so can't have been spinning, or was just windmilling).
- other engine wasn't operating under power, and may have been spinning down (blades damaged/tips shed, but no catastrophic failure so can't have been doing significant rpm).
- no bird strikes as no visible damage to wings, nose or fans.
- APU exhaust vent open, so APU was starting or started, maybe under manual control though startup is automatic after dual engine fail.
- RAT appeared to be deployed, though this might possibly have been due to ground impact. RAT deploys automatically after electrical or hydraulic failures, or on manual control.
- apparently there were still 'significant' amounts of fuel on board as there was leakage post-impact, though the tanks never actually run fully dry even if there is no usable fuel left. 'Empty' wing tanks don't necessarily much as the centre tank reserve is the last bit to go. Also being an 'ER' variant there is extra fuel storage within the fuselage.
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Fuel contamination is a possibility, water for example could freeze out of the fuel, and thaw during descent when it would be much more of a problem due to the lower tank levels. This could certainly explain a dual engine failure.
Another possibility is a catastrophic electrical failure, as per previous 777 electrical fires. Though there was no sign of fire on the ground. And each engine is independently controlled. And has failover control so any likely failure certainly shouldn't take out both engines at the same time.
Another possibility is a software glitch. These aren't exactly unknown, and in the past have been due to all kinds of unusual interactions. Sometimes they're just a mystery!
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In any case they did well to get the plane onto the airport. Once the aircraft is configured for landing and the gear is down you can't glide particularly well due to the drag, so you have to use power to maintain the descent on the glideslope, and maintain the correct approach speed.
At the stage of descent they were at they didn't have enough airspeed to make the distance, nor much height to trade for airspeed. As energy management goes it was pretty marginal, and as a problem to manage it wasn't exactly easy given it must have been all of 40 seconds from beginning to end.
At the end they seem to have hit aerodynamic stall speed i.e. the plane was too slow to fly, and fell out of the sky. Luckily it had gone far enough, and was low enough that this didn't matter too much, though it didn't do the landing gear any favours.
I would guess a few people will be hitting the sims & trying this scenario out for themselves, just to see how they get on. I would also guess some of them won't make it far enough.
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Re: F104 & other fast jets. The F104 didn't exactly have a great reputation when it was working properly, I doubt many people tried to test the glide characteristics in un-powered flight. At least not many who survived to talk about it, or if they did it was because they left the aircraft at the first opportunity.
Most current fast jets don't exactly have great flight characteristics if the engine(s) fail, for one thing they don't tend to have the same level of fallback in the electrics & hydraulics so once the engines go down, taking the generators and pumps with them, it's just you and the battery warning horn riding a plane which suddenly flies like a brick and which you can't control. So you do the sensible thing & pull the handle to get out.
On a civil aircraft this isn't an available option so you just deal with the situation, luckily the plane is designed to help you do this so the outcome is generally positive.
Yes much impportant hardware is duplicated.
How much of it is *dissimilar* duplicated?
IE if an undesired hardware or software effect emerges on one of the pair, what are the chances the exact same effect will be seen on the other one(s) too?
Does it matter?
Wrt media hype: meaning no disrespect whatsoever to the flight crew, but the media should keep schtumm a bit on this, there are examples where crew initially descrived as "heroes" have turned out to share a large part of the blame (fortunatey not many examples).
A key difference between civil airliners and jet fighters is that the latter are typically capable of supersonic flight and that is shown in many design decisions (think delta wing etc) which then have consequences regarding low-speed flight characteristics, gliding properties and whether it is actually possible to make a nice controlled flared soft touchdown.
Glide ratio is one parameter that tells you at least something. E.g. the maximum glide ratio of a C152 is around 10 or 13 or something like that and is obtained with clean wing and airspeed of 60 knots or something like that. Sounds somewhat compatible with the idea of making a landing (60 knots is pretty much the speed you'll be flying on the late final anyway). BAe Hawk is a subsonic fighter/trainer, don't know the figures but do know that it can make an unpowered landing (obviously in many cases abandoning the aircraft is still the only sensible thing to do though). SAAB Draken (an old delta wing supersonic fighter, a beautiful thing by the way, we used to have them along with MIG 21s here before they were replaced with F-18 Hornets) on the other hand has a maximum glide ratio of around 5 and it's obtained with airspeed of 500 km/h (270 knots) (at least according to a pilot joke/adage but the circle of my pilot friends does include fighter pilots). Try to fly any slower than 500 km/h without power and you'll be descending at an even steeper angle. Easy to see that the numbers aren't really compatible with the notion of a nice flare and touchdown...
Regarding the crashed 777 and flaps, the figures I saw had flaps at least partially extended and indeed it would not be an option to really retract them that late in approach even though you'd think it would be good for glide ratio (you'd need to gain a lot of additional airspeed before you can do that and there's no room for that at 400 ft and you probably don't want the airspeed anyway as you have the gear down which means you're losing a lot of energy if you try to fly fast and finally you're going to be wanting to stop the thing in a minute or so). In fact for those very reasons flaps are not really ever retracted during approach period. You're already climbing and accelerating (in other words doing a go-around) if you find yourself retracting flaps after extending them in approach.
So really glide ratio is a rather theoretical figure that depends on configuration and airspeed. A maximum glide ratio of 20 with clean wing and airspeed of 250 knots or something doesn't do you much good when in landing configuration at 400 feet and flying 140 knots and there's no way to get there anymore. So you might as well forget about it and concentrate on maintaining control and keep flying whatever airspeed you were flying and just wait and see how short you'll be (you already know you will be landing short).
(the same private pilot as before) (or then again I could just be a pimply-faced 14-year-old posing as one, couldn't really tell could you, although I guess I'd be posing as an airline or fighter pilot instead while at it...)
>>How high would it have been when it hit the ground if he hadn't?!?
The same height as if he had since the ground was not moving and the plane has to *approach* the ground !!
@Anonymous Coward - F104 - I believe they were known as the "Widowmakers" for their wonderful flight characteristics !!
Just some speculative thoughts.... The engineer in me says that a twin engine failure is fishy. Simple if they ran out of fuel or had contaminated tanks. If not that, then electronic failure.
There is no such thing as a true "accident" on an airplane. A very high percentage of catastrophic events are the result of a chain of events that string themselves together and play themselves out to an end result. Software failure is a conveinient and plausible excuse; someone's a** will be totally busted at Boeing if a software glitch did this.
There are several online reports that claim the plane lost engine power at around 200m altitude (and certainly some electronic controls). After flying long haul and coincidentally passing near Gordon Brown's motorcade (probably within 300m) the 777 loses engine power. Several online newspapers have posted that the plane eventually misses Brown's jag by "25 feet". Probably somewhat of an exaggeration, but there you have it.
Now, the jag/motorcade is probably outfitted with a cellphone/radio or similar jammer? Can anyone confirm this?
There are several companies that sell them, some of them effective up to about 50m radius (but you'd need some serious battery power to keep one that powerful running for long - not only must it generate a signal, but a signal powerful enough to drown out the targeted frequency). A post above mentions jamming signals to prevent roadside explosive devices detonating (intended to be triggered remotely by cellphone).
I do know of something called a HERF gun (a high energy radio frequency device) powered by a car battery or similar which broadcasts a focussed white noise radio signal over all radio frequencies to something like 100m away and this can repeatedly crash a computer at 100m, or interfere with a vehicle's electronics (to the point of destroying some modern IC engines). Also very useful for noisy neighbours and too-loud hifi systems. Also highly illegal. It is a focussed device and directs energy in a single direction with minimum "spread". Good luck pointing a 50kg device at a moving target though...
I assume that to be efficient (and anything near portable i.e. less than the size of a huge suitcase), a cellphone jammer would target specific, known (assumingly digital) carrier frequencies and radiates a spherical signal in all directions (i.e. unfocussed). This in itself severely limits possible broadcast power, forcing you to stick to specific frequencies.
I doubt a commercial airliner has hardened circuits. It's almost certainly industrial, but not military grade equipment. Would they be sensitive enough to respond catastrophically to a jammer? Maybe to a HERF gun, but the chances are remote. A plane does have an awful lot of sensitive elecronics and radio equipment though. The involvement of a jammer (be it mobile or HERF or similar) may be confirmed by the noise a jammer may generate on any sensitive recording equipment nearby (like when a cellphone is next to a PC's speaker). It may also be confirmed by interference at that time at a local mobile tower.
Does anyone have the exact time of the crash?
Considering that this is one of the the first (is the first?) 777 crashes, I'm sure a lot of people at Boeing want to know "why?". If Boeing sweep the incident under the carpet and quickly move on (instead of like any rational and responsible manufacturer and ground the fleet) then certainly a few more awkward questions need to be asked in the interest of public safety.
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During my time in Germany, quite a few military aircraft suffered varying degrees of interference with on-board flight management systems while using commercial (radio/tv) transmitter masts as practice targets. The consequences ranged from minor glitches to total losses. Given that these aircraft presumably had hardened/shielded systems - and still suffered interference - it seems quite likely that the mobile phone jammer carried on Gordon Brown's convoy was/could have been the cause of the 777 engines remaining on flight idle as it passed within 'a few feet' (Sky News) of the convoy. Spain would also have informed the UK of last week's arrest of putative Islamic terrorists in Barcelona - and mobile phones are in use as improvised explosive device triggers - so the UK anti-terrorists boys would have been very jumpy during Brown's trip to Heathrow. and very ready to hit the button.
First, everybody walked away, which is nice.
Now, the post re jammers has some interesting thoughts.
Start with the cellphone jammer. Not only do they exist, a vehicle mounted one in Gordon's convoy would have no realistic restrictions on size and power. Also, conceptually similar wideband jammers are allegedly used by spooks where they want to prevent remote radio-controlled bombs going off. If this kind of kit were in this picture, would we ever get to know?
Set against that is the knowledge that avionics kit goes through all kinds of EMC/RFI testing, and lightning strike testing, so for a jammer to achieve this effect after the avionics had passed its testing would be interesting.
"I doubt a commercial airliner has hardened circuits. It's almost certainly industrial, but not military grade equipment."
Bad assumption. (1) See above re EMC (2) bear in mind that much of the avionics is in one of the worst thermal and mechanical environments outside of space travel, especially the engine controls, which live on the engine and therefore get hot (and cold), and get vibrated more than a little bit. It may not be TEMPEST-class and similar fibre-optic stuff, but there's various bits of (various) Mil-spec electronic stuff up there, from chips to connectors and everywhere in between.
"a twin engine failure is fishy. Simple if they ran out of fuel or had contaminated tanks. If not that, then electronic failure."
To lose one engine is a misfortune. To lose both, at the same time, does, as you suggest, sound less than random (I believe the official quote mentions "carelessness" but that doesn't seem quite right here yet).
On the engine control side of things, in grossly oversimplified terms it works like this: each engine has its own control unit which consists of two basically similar "lanes" (similar electronics, similar software). As far as is sensibly possible, inputs are duplicated so single transducer failures etc do not lead to catastrophic results. If a failure in the controlling "lane" is detected, control is transferred to the other lane in the same box. As such, it seems almost infinitely improbable that random electronic component failures would lead to simultaneous loss of responsiveness from both engines.
Cup of tea, anyone?
It seems from the preliminary AAIB statement that the throttles (both auto and manual) were doing the right thing at the right time (asking for increased thrust), based on what the flight data recorder says. In the weeks to come, we will hopefully be hearing definitively which bit(s) between the throttle and the engine(s) resulted in the engines not providing the requested increase in thrust. Yes I'm assuming (for now) that it's not a fuel shortage or similar external event.
As already noted:
"the plane dropped intentionally so it would be nearer the ground when it hit it."
and also
"Loss of engine power was probably because there was a fuel problem caused by problem with fuel."
Eileen you have a great future ahead of you in the future, sometime after now.
I heard from Australia: " Like the near miss Qantas had last week, broken tray under sink in the forward galley, blocked drain in sink, water overflows from the blocked sink, leaks through the tray and shuts down the main switch board on a 747, the plane lands with about 20 minutes emergency battery capacity left, no electrical power from any of the engines or the APU"
Anyone steering 'planes for Quantas care to comment ?
Q: This device monitors radar and automatically launches targeted multiple electronic disruption counter measures when it detects objects travelling at speed towards the..........
007: What does this do.
Q: Pay attention James this afternoon you will be driving the PM to the airport and it is vitally important that you switch this device off before you... put that down really it's like trying to teach a computer user not to loose confidential documents.
Money penny: Pretending things are your penis really doesn't impress girls over the age of thirteen.
007: Got it drive the Austin
All: No
007: Sorry Drive the Jag to the airport and bring it back in one piece.
Money penny: Don't forget to pick up the PM
Not wanting to take anything away from the aircrew, but why do the media always hail these people as heroes? I would hazard a guess that the pilot's actions were down to self-preservation as much as the survival of the passengers. So what would be the non-heroic (or even the cowardly) alternative? For the pilot to go "Yeah, whatever", sit back and admire the rapidly approaching houses? It's not as if the pilot willingly put himself in a more dangerous situation to improve the prospects for the passengers is it?
And, @anonymous coward at 23:11, grill over intake + birdstrike = bird AND bits of grill in engines.
Surely BA the British Flag Carrier wouldn't risk the safety of an aircraft due to insufficient fuel?
"On Feb. 20, a British Airways [BAB] 747 (Flight 268 en route from Los Angeles to Heathrow) diverted itself to Manchester after declaring a Mayday for being short on fuel."
http://findarticles.com/p/articles/mi_m0UBT/is_8_19/ai_n11844072
And an actual AAIB documented example...
http://www.aaib.dft.gov.uk/cms_resources/Boeing%20747-443,%20G-VROM%2007-07.pdf
http://query.nytimes.com/gst/fullpage.html?res=9C0CEFDA143BF934A15752C0A966958260
.
Deary me if you are going to provide examples of aircraft running out of fuel then at least provide positive examples....!!
The British Airways 747 from LAX actually landed with plenty of fuel the only reason they did an emergency landing was beecause of crew fuel mismanagement en route.
The Avianca 707 flight is a good case of Human error (Or to put it better an example of Human factors and Cockpit resource management). Even though they knew they were low on fuel due to a combination of circumstances they didn’t call an emergency approach where they would have received priority routings to land. (And therefore would have landed safely)
Might I suggest you read the official accident reports rather than relying on newspaper 'cuttings?'
OK, I accept "successful crash". The aeroplane was more broken than I realised.
Back in the 1980s I was told serious mishaps were more common when the first officer was flying, and They had investigated why. It wasn't because the first officer was an inferior pilot, but because the captain was a rather poor co-pilot (ie, the pilot not flying, whose support was vital.)
If the captain of this plane had tried to take control when there wasn't time for an orderly transfer, he might've caused a worse outcome. He deserves respect for not fouling things up.
Heroes: I met a bloke who'd witnessed a full gear-up landing of a 747 full of passengers; it was technically perfect and the airframe was reusable. They asked the pilot how he did it and he said "I put the passengers out of my mind and pretended I was doing it in the simulator".
You could argue that heroism's where someone's Thinking of the Children and all fired up on adrenaline, and what airline pilots do in a jam is "Just Doing My Job". You've still got to be impressed when they do it exceptionally well.
What a dull post - has anyone used the alien yet?
Delays in sending buses out to collect the passengers
Locked up with only limited water for ages
Not allowed to a toilet unaccompanied
Detained for hours without meals
No provision by BA for their eventual onward travel
No possibility of getting their bags and no financial or other arrangements to get them home
Only useful individual seems to have been a PC Plod who managed to persuade taxi drivers to take those from London home on promise of payment on arrival at destination.
How many of them have got all their possessions yet? How many will EVER get all their possessions?
PC Plod: 10 out of 10
BAA 1 out of 10
BA 0 out of 10
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