Tuesday, 10 January 2006 01:50
Dear Captain Lim,
I am a great fan of flying and am most interested in designs and technology aboard the aircraft. Three things have popped into my mind:
One - is it ever possible for a plane to land so hard that the tail falls off? If so, would it be the pilot*s fault for reversing the engines too early?
Two - can pilots land under a condition that one of the engines is not operating and they have to "shut it off"? It must be hard to have to fight against the constant change in direction, say, if your left engine had failed.
Lastly - I have seen in videos where planes land on one wheel. Is it really common for that to happen?
The undercarriages of planes are designed to be incredibly tough. For instance, on the Boeing 777, very thorough tests had been carried out during the development stage. The plane was subjected to quite dreadful things before being even put to passenger service.
During the test, the plane was loaded up to maximum weight (about 297 tons or 632,500 lbs) by the use of water barrels or bags of sand, making sure that it could fly with a weight far higher than what it would be for normal service. Then they loaded the tail with heavy objects, such as bags of lead to make sure it could fly with all the weight at the back, at the front or at one side. They then tested the plane to see how it would take to the harsh landings. Instead of letting the plane do a normal soft landing, they would just drive it down the runway with a great thump and examined how the structure would react.
These tests were to ensure that, in normal circumstances with passengers where it would not get anywhere near these kinds of situations, the airplane would still be fully controllable and safe to land at. With such stringent tests, if the tail were to fall off, the landing gears would have to collapse first. I wouldn't foresee such an event unless it was a real uncontrolled crash.
Further, early initiation of reverse on the engines would not have any effect or contribute to the "tail falling off". In fact, reversing the engines as soon as the plane touches down is a good pilot technique as it shortens the landing run.
Landing with one engine "shut off" is not unusual as it is designed to be capable of doing so.
Landing on one wheel is not a common thing but it can happen on smaller twin-engine planes. Yes, there is a checklist for pilots in case they are caught in a situation where one of the main landing gear fails to extend. Properly handled, a landing with one gear extended is not a serious emergency.