I was wondering what your take is on the Air France 447 crash where a high altitude stall caused the plane to lose lift and plunge.
I would have thought that it is basic knowledge for all pilots that pulling out of a stall requires pointing the nose of the plane down to increase air speed and lift. However, they did the opposite and pointed the nose up, making the situation worse.
How could they have gotten it so wrong?
Also, I didn't think turbulence could cause the plane to stall. How did this happen?
Jim
Hi Jim,
The Air France Flight 447 crash was a tragedy that could have been prevented if pilots were given more training on recovery from a jet upset. Most pilots were trained on stall recovery technique during their basic flying school days but it appears that this exercise was no longer required because it was thought that modern planes have been designed to make it unnecessary. Well it appears to be a mistake.
In the instance case, it was unfortunate that besides getting into a high speed stall, the plane had unreliable airspeed due to the pitot tubes being blocked by ice. There were conflicting information of aural stall warning and erratic airspeed. The nose up was caused by the pilot applying full power - this was not the correct technique for initial recovery from a stall for a jet plane.
It is easy in hindsight to ask why it had gotten so wrong. It seems there were no good visual horizon for a proper recovery due to the weather and aggravated by conflicting aural and airspeed information.
Turbulence did not cause the plane to stall. It was the combination of many other unfortunate circumstances – mainly the loss of reliable airspeed caused by the frozen pitot tubes.
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You write "by the pilot applying full power - this was not the correct technique for initial recovery from a stall for a jet plane" Yes and NO. We know this after the accident. You must don't forget the Airbus procedure was completly opposite at the time of the accident: in case of stall warning: Go around id Max power! Now after this accident and the Perpignan accident, it is officially completely opposite...
Jean(John) E., France ,
06 Dec, 2011
+0
GPS-system on board
In this case, like in my cases, where commercial airline crashes happen, it's usualy not just one thing that causes the crash. In the movie shown above we are able to see a tiny part of what went wrong during this accident. The truth is, it's far more complicated than that. Due to a hardware error ( frozen pitot tubes ), the plane's software malfunctioned as well, leaving the pilots in total mystery about the alltitude, cruising speed etc. The complete software system of airbus simply wasn't designed to cope with this situation aswell as the pilots, who weren't trained for a stall situation. A simple GPS-system could have made the difference in this case. Because at high altitude ( flying trough thin air) a difference of some 50 km/h can mean the difference between flying regular or stalling.
beerza ,
11 Jan, 2012
+0
...
One more possibility as to the crash is that the pilot have been put to mistrust by the airplane. I saw in one documentary about the AF447 crash, the procedure for pitot tube failure is to apply 80% power and 5 degrees nose up to maintain speed. But since the autothrottle was acting upto the final disconnect, the engine power could have been lower as per the auto throttle systems to get through the turbulence, but it was not reflected in the thrust levers. So, the pilot may have assumed he was having 80% thrust when in fact he was having insufficient thrust after disconnect, causing him to lose speed with the nose up attitude and hence stall.
Venkatesh ,
20 Jan, 2012
+1
Pitot Tube Anti-ice
I was just an amateur pilot but how the... Frozen pitot tubes? One of the most important things we learned at the ground-school was never to mess up with snow and ice. Did they forget to turn on the "anti-ice"? Or false indication the pitot tube "anti-ice" was on (similar to DC-10 cargo bay doors)? Or the heater was too weak for the icing conditions?
MikeVictor ,
23 Jan, 2012
+0
Pitot Tube Ice
Well, it's very possible that flight 447 encountered SLD icing and the pitot heat just couldn't keep up... If you look at the flight path and altitude in relation to the precipitation they were flying through and around at the time of the accident it's easy to see how Supercooled Liquid Droplets could have been present and overwhelmed the pitot heat system.
