10/15/2012

Watch a plane crash

Last week in the evening, the UK Channel 4 TV program showing a plane crash made fascinating viewing. It might have saved some lives.


In order to study what actually happens when a big aircraft crashes, a team of scientists spent some years preparing to deliberately crash a Boeing 727 aircraft in the desert in Mexico. For this, the air crew, composed of pilots and scientists setting up the interior experiments, had to parachute out of the aircraft. When the pilot left the aircraft it was controlled from an accompanying light aircraft by exactly the sort of hand-held remote control that we see at demonstrations of sophisticated model aircraft, such as ones organised regularly in Versoix.

Although the programme is available for UK viewers on the Channel 4 web site, it cannot be accessed from Switzerland because of copyright reasons. However, the film of the actual crash is available via YouTube.

The programme started by talking about some of the real crashes in which some passengers were killed, whilst others lived. Some of these passengers spoke, often with unsuppressed emotion, about their experience. They would have asked themselves afterwards, possibly with a guilty feeling, why they lived whilst others died.

Some changes had already happened as a result of these real earlier crashes. The emergency exits are made wider and more accessible by removing a seat next to them. This has the side effect of giving much more leg room to seats behind them, so that these seats are more favoured (and sometimes can now be obtained by paying a higher fare).

This deliberate crash showed up an extra hazard in the aftermath of the crash. There had been a worry about heavy luggage items falling from the overhead lockers, but these normally stayed shut. However, modern aircraft have a lot of cabling which runs in conduits above the passengers, and a lot of this came down, making it much more difficult to move down the aisles.

For the crash there were a number of dummies put in different positions. It was demonstrated that the brace position which we are now told to adopt is probably optimum, though the action and reaction of the crash could cause a broken ankle from the lower leg rebounding and hitting the base of the seat. This is, however, preferable to the broken neck of someone simply seated with the seat belt attached. As for someone without a seat belt attached, they are forced under the seat in front at a rather rapid rate.

One of the lesser known facts about aircraft is that the main landing gear under the wings is designed to snap off on impact, thus meaning that the main part of the fuselage hits the ground and then slides along relatively unscathed until friction stops it.

In the deliberate crash, the aircraft hit the ground nose first, and the nose wheel, which is fixed, went up into the fuselage and caused the cockpit and front part of the aircraft to shear off and finish separate from the main part of the aircraft, with little chance of survival for the pilots and first class passengers. Most of the passengers in the centre or rear of the aircraft would have survived, some even unscathed. However, in a minority of cases the aircraft hits the ground tail first, thus explaining why one of the real passengers in a real crash, seated in row 1 of the aircraft, quickly recovered consciousness and got out of a hole next to him.

Although it is highly unlikely to happen to us, since air travel is a very safe form of transport, the lesson that I learned from watching this documentary was that I should pay attention to the pre-flight safety announcements about brace position and emergency exits. Maybe this advice might one day save the life of someone reading this blog.

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