air france A330 crash

[cptn_star]

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apil ko ha....ang pitot tubes sa airbus a330 duna man na heater to protect from icing at high altitudes...ngano kaha mao na suspect noh? sakto on the possible loss of proper air speed indicator on the cockpit...ambot lang sab. latest evidence point to mid air disintegration.

dili lang airbus 330 ang naay heated pitot tubes...almost all aircraft flying nowadays are equipped with heated pitot tubes...i couldnt actually welcome the idea of pitot tube failure as a cause...the most probable cause that would be plausible for me is extreme wind shear that could have tossed the aircraft at just about any attitude...that may have contributed to structural disintegration...

[Tarmac]

apil ko ha....ang pitot tubes sa airbus a330 duna man na heater to protect from icing at high altitudes...ngano kaha mao na suspect noh? sakto on the possible loss of proper air speed indicator on the cockpit...ambot lang sab. latest evidence point to mid air disintegration.

Yes, the A330 pitot tubes have heaters, but in a thunderstorm the ice can accumulate so rapidly (almost instantaneously) that the heaters are overwhelmed. But the heaters usually manage to melt the ice away after a few minutes.

Unreliable airspeed indications is one of the seven memory items for the A330. In other words, the pilots must know by heart the first few things needed to deal with an unreliable airspeed condition. And this entails disconnecting the autopilot and flying the plane manually. Why? Because the plane doesn't know how fast the plane is flying. Because it doesn't know how fast it is flying the autopilot might attempt to maintain the wrong speed (for example, the autopilot tries to maintain a commanded speed of 280 kts indicated airspeed when in reality the plane is only flying at 200 kts and is close to stalling).

To counter this, the pilots must fly the plane manually using a certain pitch and power combination. The pilots know that if they want a certain speed, they must keep the engines at a certain setting and the plane's nose attitude at a particular number of degrees. They don't need to to do this for the whole flight, they only need to do this until the airspeed indication comes back to normal which it normally does after a few minutes (usually when the pitot heat finally melts the ice away). A few weeks ago at the height of Tropical Storm Feria, an airliner from one of the local airlines reported an unreliable airspeed indication after flying into a region of heavy rain. The crew dealt with it properly and the plane landed safely.

In the case of AF447, the unreliable airspeed indication was a factor in the crash in that it was the first abnormal condition detected and reported by the maintenance computers. Unfortunately, things must have snowballed so rapidly from there that the crew was overwhelmed or distracted so much that they lost control of the aircraft. Consider the following: It was a dark night. They were flying through a line of thunderstorms. They were being tossed about (the pilots reported heavy turbulence). They must have been busy trying to pick their way through the weather. That in itself is cause for a lot of anxiety in the cockpit. Then inadvertently, they fly right smack into a thunderstorm and lose airspeed indication. The anxiety level suddenly kicks up several notches. Was it enough to overwhelm the crew? We'll find out when the black boxes are recovered (if they are recovered).

With regard to similarities between Air France 447 and the Yemenia crash, I don't think aircraft system failures were a factor in the latter accident. They were maneuvering to land off a very demanding approach procedure. It was also a dark night with strong, gusting winds. I have my suspicions but I don't think the plane had anything to do with it.