The Crash of GermanWings Flight 4U9525.

Yesterday an Airbus A320 operated by German airline GermanWings crashed into mountains in the French Alps en route from Barcelona, Spain to Dusseldorf, Germany. Due to the force of the crash all 150 passengers and crew on board were killed. There appears to have been no communication with Air Traffic Control (ATC).

According to third party flight tracking data that may not be 100% accurate the aircraft took off as normal for Barcelona and turned out across the Mediterranean Sea where it gradually climbed to it's approved cruising altitude of 38,000ft (10,850 metres). A minute later the aircraft began a sharp but controlled descent as if making an approach for landing. After 10 minutes of this descent the aircraft had dropped to an altitude of 6,800ft (1,940 metres) at which point it collided with a mountain side likely resulting in a fiery explosion.

In the absence of any other information it is hard to offer any explanation of why the crash occurred particularly because I am not a pilot nor an aviation expert. However I suspect there are a series of scenarios that will be looked at.

The first of these is that the pilot did it on purpose as part of a suicide bid. This is something that investigators always have to rule out but it is extremely unlikely because all commercial airliners have at least two pilots on board. Therefore they would both have had to made a suicide pact and then kept it secret from all the other flight crew and their colleagues on the ground which is as unlikely as it sounds. So this is something that the investigators will look at as a matter of routine but it's something that only really happens in movies.

There has also been some speculation about the computer systems on the A320 which operate something known as envelope control. Essentially this means that the computer monitors the parameters of flight such as speed, altitude aptitude etc. If it finds something to be outside of the normal parameters (the envelope) it automatically takes action to correct the problem.

Back in November 2014 an airworthiness notice was issued for the A320's envelope control system after an aircraft belonging to GermanWings parent company Lufthansa went into a rapid descent after the computer system wrongly decided that is was climbing. I should point out though that the pilots can over-ride the computer and that is exactly what happened in November which is why all similar aircraft were not grounded.

I also find it impossible to believe that an experienced crew would have failed to notice that the plane was descending for a full 10 minutes not least because ATC would have noticed any unapproved descent and got on the radio demanding to know what the crew were doing.

Another possible explanation is that there was an engine failure but the consistent airspeed throughout the descent would seem to rule that out. Plus it is almost impossible for both the engines on an A320 to fail at the same except if there was something extremely random like birds striking both engines but that would normally trigger a sharper descent.

It is possible that one of the aircraft's engines failed or experienced a flame out and the crew descended to slow the aircraft to a speed where they could attempt to restart the engine. However that would have left them with a good five minutes to communicate with ATC to explain the problem if for no other reason then to make sure they didn't collide with any other aircraft in the area. Plus flying that low over a mountain range is considered more dangerous then trying to continue on one engine.

The only other explanation I can think of is that the aircraft suffered some sort of catastrophic control panel failure that left the crew both unable to correctly measure their altitude, speed etc and to communicate with ATC. I wouldn't like to speculate on what could cause such a failure but it could be a computer problem or something as simple as a fire that destroyed the electronic circuits. 

17:40 on 25/3/15 (UK date).