L
Lincsbodger
Just watched an interesting documentary about Air France Flight 447, which was a scheduled commercial flight from Rio de Janeiro to Paris, an Airbus 330, that crashed into the Atlantic Ocean on 1 June 2009, killing all 216 passengers and 12 crew members.
The guy pointed out that these days, air crashes are usually the result of a chain of unusual events which singly arent critical, bu together bring it down.
Since the black boxes are two miles under the sea, its unlikely you'll eveer get to the truth, but this guy, a retired air crash investigator, has put together a theory, backed up with evidence and tests in a simulator. The sequence of events goes like this:
1. AF447 flies towards a small storm, behind which is a humongous storm. The radar cant see the large storm behind, because the small hides it - the radar cant see through the small storm, until its too late. AF447 is on autopilot.
2. AF447 finally spots the massive storm, and is forced to go through it.
3. The Auto Thrust system adjust thrust to maintain airspeed slightly slower. You go slower in a storm otherwise turbulence rips the plane apart. The pilot doesnt notice the Autothrust has adjusted the speed because unlike older mechanical controls, the thrust levers in an Aribuss dont move when adjusted by auto systems.
4. The storm has exactly the right rare conditions for a very rare phenomena to occur - supercooled water. This is very pure water well below freezing point that is still liquid. When it hist the pitot tibes on the plane, it freezes solid instantly, blocking the tubes. The flight computers are now well stuffed, because airspeed is acritical piece of information.
5. Without airspeed data , the autopilot kicks out. 20 seconds later the Autothrust system also disengages.
6. The pilots are forced to manually fly the plane, with inaccurate flight data. Basically, they're now guessing.
7. Because they dont know the true airspeed, they probably did exactly what the book says, which is reduce thrust to 85% and raise the nose 5 degrees, probably unaware the autothrust already reduced airspeed.
8. The plane then stalls, because its going to slow. One wing stalls before the other. IN a simulator, a test pilot did this and lost 19,000 ft of altitude before he recovered out the stall, in a fighter plane. Commercial pilots are no longer taught to recover from extreme stalls. The procedure to recover from stall is to force the nose down vertical to get air flowing over the wings and recover lift. If one wing stalls before the other, it throws the plane into a violent corkscrew, making it harder to recover.
So, it looks like the managed to get the plane straight and level, but ran out of height, and hit the water flat and horizontal. The scandal is that the problem with pitot tubes freezing up was already known ,and all pitot tubes were being replaced, but AF447 hadnt been done and was flying on old design pitots.
It was all very interesting...........
The guy pointed out that these days, air crashes are usually the result of a chain of unusual events which singly arent critical, bu together bring it down.
Since the black boxes are two miles under the sea, its unlikely you'll eveer get to the truth, but this guy, a retired air crash investigator, has put together a theory, backed up with evidence and tests in a simulator. The sequence of events goes like this:
1. AF447 flies towards a small storm, behind which is a humongous storm. The radar cant see the large storm behind, because the small hides it - the radar cant see through the small storm, until its too late. AF447 is on autopilot.
2. AF447 finally spots the massive storm, and is forced to go through it.
3. The Auto Thrust system adjust thrust to maintain airspeed slightly slower. You go slower in a storm otherwise turbulence rips the plane apart. The pilot doesnt notice the Autothrust has adjusted the speed because unlike older mechanical controls, the thrust levers in an Aribuss dont move when adjusted by auto systems.
4. The storm has exactly the right rare conditions for a very rare phenomena to occur - supercooled water. This is very pure water well below freezing point that is still liquid. When it hist the pitot tibes on the plane, it freezes solid instantly, blocking the tubes. The flight computers are now well stuffed, because airspeed is acritical piece of information.
5. Without airspeed data , the autopilot kicks out. 20 seconds later the Autothrust system also disengages.
6. The pilots are forced to manually fly the plane, with inaccurate flight data. Basically, they're now guessing.
7. Because they dont know the true airspeed, they probably did exactly what the book says, which is reduce thrust to 85% and raise the nose 5 degrees, probably unaware the autothrust already reduced airspeed.
8. The plane then stalls, because its going to slow. One wing stalls before the other. IN a simulator, a test pilot did this and lost 19,000 ft of altitude before he recovered out the stall, in a fighter plane. Commercial pilots are no longer taught to recover from extreme stalls. The procedure to recover from stall is to force the nose down vertical to get air flowing over the wings and recover lift. If one wing stalls before the other, it throws the plane into a violent corkscrew, making it harder to recover.
So, it looks like the managed to get the plane straight and level, but ran out of height, and hit the water flat and horizontal. The scandal is that the problem with pitot tubes freezing up was already known ,and all pitot tubes were being replaced, but AF447 hadnt been done and was flying on old design pitots.
It was all very interesting...........
