Aircraft Accident Investigation

Aircraft Accident Investigation

 

Air Asia plane exploded after hitting water? This is a good question so far. Part of the plane's tail was broken into pieces and a flight data recorder was thrown more than a kilometer (.62 miles as the news show on the media)

All aircraft accidents are different; there are certain elements that are common to aircraft impacts and wreckage distribution. By organizing those elements, we can predict and explain most impact situations.

 

Some, for various reasons, will defy any rational explanation.

 

The two questions that usually need to be answered are:

 

1.What was the attitude of the aircraft at impact?

 

 

2.Was this impact survivable?

 

 

Influence of Aircraft Velocity and Impact Angle

 

Crash dynamics and wreckage distribution is influenced primarily by aircraft velocity and impact angle.

 

The velocity of the aircraft generally determines the degree of breakup and destruction of the wreckage.

 

The impact angle determines how the wreckage will be distributed. We will deal with each of these separately.

 

Water Impacts

 

These deserve a brief mention. What happens when a plane hits the water?

 

Actually, it is primarily a function of velocity. If the plane is going fast enough, the water is a solid object as far as the plane is concerned. It comes apart in about as many pieces as it would if it had crashed on land. At the other extreme, a plane that was deliberately ditched will probably sink to the bottom in one piece.

 

In a water impact, there is an impact angle, but it is related to the wave action on the surface of the water. If the water was absolutely calm, then the impact angle may be determined by examination of the wreckage. If there was heavy wave action, impact angle becomes meaningless as you don’t know whether the plane impacted on the front or backside of wave.

 

What is the significance of the distribution of wreckage on the bottom of the lake, ocean, or river?

 

In general, the wreckage distribution doesn’t mean much unless it resulted from an inflight breakup.

 

 

The actual distribution is influenced by depth, currents and the tendency of various parts to float (or be slightly buoyant) or to sink in different fashions. Some parts of the plane will sink like a rock. Others will sink like a dinner plate. Try it and you’ll see the difference.

 

One rule that does hold up fairly well is the dispersed part rule. A portion of the airplane or its contents found at a significant distance from the main wreckage probably came off inflight.    

 

Source: Aircraft Accident Investigation (Richard H. Wood / Robert W. Sweginnis)