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Investigators Suspect Computers Doomed Air France Jet
DesScorp writes "Investigators working with the wreckage of Air France flight 447 believe the aircraft suffered cascading system failures with the on-board computers, eliminating the automation the aircraft needed to stay aloft. 'Relying on backup instruments, the Air France pilots apparently struggled to restart flight-management computers even as their plane may have begun breaking up from excessive speed,' reports the Wall Street Journal. Computer malfunctions may not be an isolated incident on the Airbus A330, as the NTSB is now investigating two other flights 'in which airspeed and altitude indications in the cockpits of Airbus A330 aircraft may have malfunctioned.'"
I think you both are thinking of the FAA. The whole purpose of the NTSB is to research and investigate civil transportation accidents. They then present their conclusions and recommendations to the regulating authority in that industry. For the airline industry, the FAA then has to implement any recommendations. For the most part, the FAA does not always implement all the recommendations due to cost, business concerns, practicality, national concerns, politics, etc.
In this case, the black boxes have not been recovered and it might be very difficult to pinpoint a cause without them. But the NTSB knows of similar cases that may have occurred in the US that did not lead to accidents. If there job wasn't to ensure that the fleet of aircraft in the US is safe, they may just sit on their asses and do nothing. But it is their job to ensure safety so they will investigate whether this might have led a situation similar to the Air France flight. They will probably share their data with Air France, the Brazilian authorities, Airbus, the FAA, etc when the investigation is concluded.
Well, there's spam egg sausage and spam, that's not got much spam in it.
A GPS recorded speed of 100mph, into a 50mph headwind = 150 mph airspeed.
Have you thought this out? Why would flying into a headwind speed up the plane? Just sayin'...
Lets say the pilot wants to fly at 500 knots AIS (Indicated Air Speed). They set ground speed to 500 knots with GPS but the air is going the other way to 100 knots. Airspeed is now 600 knots.
http://michaelsmith.id.au
it doesn't speed up the plane... but the plane is moving 150 mph compared to the air. That's air speed.
Let's reverse it.. A plane must travel so fast to stay in the air.. let's say 130mph to keep things sane. So if you have a plane flying at 140mph with no wind any direction, the plane will stay up. That same plane could slow to 125mph with a 15mph headwind, and still stay up since in effect the plane is "traveling" at 140mph. Now if there was a TAIL wind of 15mph while the plane was flying at 125mph, the effective speed of the plane would only be 110mph and it wouldn't be able to stay up, it would stall.
Actually, the NTSB should be involved in this investigation. I think you can get up to 5 organizations joining to investigate a crash.
1) Country of Origin (Brazil)
2) Country of Destination (France)
3) Country of Carrier (France)
4) Country of Airframe Manufacturer (France/Germany/EU)
5) Country of Engine Manufacturer (US)
Notice that #5 was US. The engines on the plane in question were GE.
--
The internet is the greatest source of biased information in the history of mankind.
Scary stuff.
The Wall Street Journal article oversimplifies the problem with the Airbus
design philosophy. In effect; Too Damn Much reliance on the automated flight
control system for basic safety-of-flight.
A prime example?
Rudder hinges.
Airbus has notoriously
http://en.wikipedia.org/wiki/American_Airlines_Flight_587
underbuilt the rudder hinges on the A300 (and, no doubt, the A330) in the
interest of lightness and efficiency. They have chosen to rely on the
automated flight control system to limit loads on the structure, instead of
building the necessary robustness into that structure.
This is great when flight conditions are all peachy, but in a thunderstorm, at
night, with sensors (iced-up pitot tubes?) that are prone to failure, well
then you have a failure scenario that the designers never built into their
simulations, and the rescue/recovery teams in the south Atlantic find the
rudder 37 miles from the rest of the wreckage.
Forwarded from a colleague (names redacted);
>> This from a friend and NWA pilot I flew the B-757
>> with out of our Tokyo base.........Now obviously on the A-330
>>
>>
>> Well, I'm sure you have all heard of the Air France accident. I fly
>> the same plane, the A330.
>>
>>
>>
>> Yesterday while coming up from Hong Kong to Tokyo , a 1700nm
>> 4hr. flight, we experienced the same problems Air France had while
>> flying thru bad weather.
>> I have a link to the failures that occurred on AF 447. My list is
>> almost the same.
>> http://www.eurocockpit.com/images/acars447.php
>>
>> The problem I suspect is the pitot tubes ice over and you
>> loose your airspeed indication along with the auto pilot, auto
>> throttles and rudder limit protection. The rudder limit protection
>> keeps you from over stressing the rudder at high speed.
>>
>> Synopsis;
>> Tuesday 23, 2009 10am enroute HKG to NRT. Entering Nara Japan
>> airspace.
>>
>> FL390 mostly clear with occasional isolated areas of rain,
>> clouds tops about FL410.
>> Outside air temperature was -50C TAT -21C (your not supposed to get
>> liquid water at these temps). We did.
>>
>> As we were following other aircraft along our route. We
>> approached a large area of rain below us. Tilting the weather radar
>> down we could see the heavy rain below, displayed in red. At our
>> altitude the radar indicated green or light precipitation, most
>> likely ice crystals we thought.
>>
>> Entering the cloud tops we experienced just light to moderate
>> turbulence. (The winds were around 30kts at altitude.) After about
>> 15 sec. we encountered moderate rain. We thought it odd to have
>> rain streaming up the windshield at this altitude and the sound of
>> the plane getting pelted like an aluminum garage door. It got very
>> warm and humid in the cockpit all of a sudden.
>> Five seconds later the Captains, First Officers, and standby
>> airspeed indicators rolled back to 60kts. The auto pilot and auto
>> throttles disengaged. The Master Warning and Master Caution
>> flashed, and the sounds of chirps and clicks letting us know these
>> things were happening.
>> The Capt. hand flew the plane on the shortest
>> vector out of the rain. The airspeed indicators briefly came back
>> but failed again. The failure lasted for THREE minutes. We flew the
>> recommended 83%N1 power setting. When the airspeed indicators came
>> back. we were within 5 knots of our desired
The problem largely is that the difference between airspeed and ground speed can mean the difference between supersonic airflow over the airframe, or not enough to maintain flight. At cruising altitude (FL300 and above) you don't have a very large speed differential between these two danger areas, so windshear is something you want to avoid. (i.e. Thunderstorms)
Your question about wind speed is a little difficult to answer, it would depend on the aircraft type, but then it also depends upon what you are doing in the aircraft too, straight and level, in a turn, high g, and so on, so there are a whole host of factors to consider.
Both are important.
Too little airspeed = too little lift and a stall (which is very dangerous on something as big as an airliner, though theoretically recoverable at that altitude granted you'll waste quite a bit of fuel and scare the living daylights out of the passengers).
Too much airspeed = shock waves rip the wings right off the plane. They're not fighters and while those wings actually are pretty strong they can only make them so heavy and be able to carry payload.
This video shows an Airbus pilot switching off the flight computers then barrel rolling an A320:
http://www.youtube.com/watch?v=P2KygSyVE58
Any belief that Airbus pilots are somehow under the communist thumb and that square-jawed Boeing pilots would heave manfully at the controls and save the say is, um, 100% laughable.
FTA: "...the crew apparently shut down or tried to reboot their primary and secondary computer systems."
Where do they get this garbage? Do they make it up based on their experience with Windows ME?
FWIW, Airbus have *five* flight computers (not "primary" and "secondary") and any one of them can fly the 'plane. If they're all gone then the aircraft is already in little bits so no, you wouldn't ever be under the dashboard trying to 'reboot' them instead of flying (whatever 'reboot' means - they're designed to reboot themselves under a watchdog timer).
No sig today...
If you google "NTSB investigates Boeing" you 6730 searches with the most popular one about the 737 rudder problem which Boeing acknowledged and fixed. If you google "NTSB investigates Airbus" you get 4990 results. It would appear to me the NTSB investigates all accidents and near accidents regardless of the manufacturer. As a government agency the NTSB will tell the press that they are doing it. Or would you rather they tell no one what they are doing? It's their job to investigate especially in a case where the blackboxes might not be recovered. Now if this was an airplane model that didn't fly in the US, the NTSB would not investigate as it is out of their mandate. But since the Airbus 330 does fly in the US, they have to seriously look at any issues. Or would you rather a crash occur in the US before they get involved.
Well, there's spam egg sausage and spam, that's not got much spam in it.
This video shows an Airbus pilot switching off the flight computers then barrel rolling an A320:
http://www.youtube.com/watch?v=P2KygSyVE58
It's a full scale simulator not a real aircraft, you can see the border of the simulator room projection screen outside of the cockpit. Do you really thing that a man performing a barrel roll with a jumbo jet have the time to explain in a relax manner what's happening ?
It's only a demonstration about how the flight computers limit the human command to stay in flight parameters ( and prevent you to attend stupid maneuver like a barrel roll).
There are certification bodies in the US, Europe and many other countries that define what that margin is. The greater the margin the heavier the plane will be, the more fuel it will need and the less load it will be able to carry. So your question really is asking if all these certification bodies are idiots. They are not and are definitely better at it than your armchair speculation. Simple evidence is looking at the rate of crashes and fatalities over time despite the increasing amount of air travel.
How come you don't walk around always wearing a bulletproof vest? Why aren't all your house doors, windows and walls armoured? Because there are costs and benefits and they all have to weighted together to come up with something appropriate.
It would not tear apart in simple level flight within the normal speed range. It could be torn apart going too fast (ie beyond the certification limits imposed by those national bodies) but even then would not be in level flight but likely dropping. It was a massive thunderstorm with huge air currents they were going through. This is an example of what planes can survive where the plane looped, parts flew off and the wings got permanently bent. This is an example of a certification test for wing strength. FAA regulations require that wings survive 1.5 times (150 percent) of the highest aerodynamic load that the jet could ever be expected to encounter during flight for 3 seconds. That applies to all airliners. The pitot tubes keep being mentioned because they tell you how fast you are going relative to the surrounding air. If they iced over then you don't know and going to slow will result in a stall, going fast increases discomfort and going too fast can result in bits of the plane breaking off.
But to be clear it required abnormal circumstances to break apart. Way beyond anything normally or abnormally encountered. If the circumstances happened with any regularity then you would hear about this kind of accident more often.
The fault messages are generally intended for maintenance so that when the plane arrives they can be repaired as quickly as possible and the plane turned around. They also help with long term tracking of wear and tear. Current blackbox recorders record a huge amount of data which would be infeasible to transmit, especially when it has to go via satellite such as when over oceans. Plane crashes are very rare (that is why they make the news) and it is even rarer to not find the blackboxes.
You overestimate the ability of humans. We are long gone from the days of the lonesome hero sweating it with the control stick. A flying plane is a complex mechanism. You have many control surfaces, air pressures and speeds, centre of gravity, fuel consumption, engine abilities, aerodynamics etc all to take into account. A computer program can do all of that so many times better than a human which includes being both more economical and reacting quicker. The people who make planes are not idiots. Ultimately you have to take the underlying tools you use as is. For example I don't see you insis
Give me a break. This whole thing was taken in a simulator, which are *programmed* to behave how they think the airplanes will behave, using recorded data from test flights to help. Because they do not test the airframes in extreme attitudes (especially barrel rolls), they have little to no data with which to program the simulator, making demonstrations like this complete nonsense.
There are three replies to GP, and they all totally miss the point, including yours.
He wasn't trying to say that you can do a barrel roll in A320.
He was saying that you can turn off computers in A320, and still retain full manual control of the airctaft.
Coffin corner does not refer to a simple underspeed/overspeed condition. Limiting factor for speed at high altitude is Mach number, not IAS. Exceeding Mcrit leads to shockwave formation on the leading edge of the wing. This moves the centre of pressure rearwards and causes an uncontrollable nose-down pitching moment known as Mach Tuck.
It is this that can cause speeds to rise to the point where they're damaging to the airframe.
At coffin corner, slowing down will give pre-stall buffet, while speeding up gives mach buffet, the precursor to mach tuck. It's almost impossible to tell the difference between the two. Additionally, given the high TAS even small control inputs can have very rapid and extreme effects. It is exceptionally difficult to hand-fly an airliner at high altitude, especially without the benefit of automatic trim.
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