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SteamWake
10-26-09, 12:45 PM
Now dont get your hopes up Im not goin anywhere.

Those were the last words of a brave pilot who ditched his plane in the carribian saving all the passengers but he himself died.

The part I dont understand is yea he lost one engine but was at 3,500 feet and still had one engine running. Why was a ditching necessary?

http://www.timesonline.co.uk/tol/news/uk/article6889041.ece

Schroeder
10-26-09, 01:59 PM
Maybe because of this:
Mansell’s father, Roger, said his son had repeatedly told him that the Caribbean airline’s planes were overloaded as passengers and luggage were not weighed properly.If the plane is in a critical load out to begin with it gets pretty difficult to stay in the air with the one engine down.

GoldenRivet
10-26-09, 02:48 PM
you will hear about twin engine aircraft the following statement:

"The purpose of having two engines is so that when one fails, the other will fly you to the scene of the crash."

there is some degree of truth to that statement, especially if the aircraft is operating at high weight loading, in a hot or humid environment.

if you ask a person what percentage of performance degradation a twin engine aircraft will lose when one engine fails, the answer is almost always "fifty percent"

in fact, the percentage of performance degradation is closer to eighty percent.

SteamWake
10-26-09, 02:54 PM
80% Hrm... care to explain the physics behind that I mean its thrust to weight / drag right?

With a featherd prop I dont think the drag would be that much different.

GoldenRivet
10-26-09, 03:00 PM
From learn to fly airplanes web site. (Im without the benifit of consulting my own multi engine lesson plan at the moment for a brief explaination)

"There is a dramatic performance loss associated with the loss of an engine, particularly just after takeoff. Any airplane’s climb performance is a function of thrust horsepower which is in excess of that required for level flight. In a hypothetical twin with each engine producing 200 thrust horsepower, assume that the total level-flight thrust horsepower required is 175. In this situation, the airplane would ordinarily have a reserve of 225 thrust horsepower available for climb. Loss of one engine would leave only 25 (200 minus 175) thrust horsepower available for climb, a drastic reduction. Sea level rate-of-climb performance losses of at least 80 to 90 percent, even under ideal circumstances, are typical for multiengine airplanes in OEI flight."

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the above paragraph refers specifically to climb performance.

a properly loaded multi engine aircraft being operated within standard atmosphperic conditions with One engine inoperative would be capable of maintaining straight and level flight, however, given the loss of power it would be incapable of climbing beyond its maximum single engine altitude.

when you add the adverse loading condition to the equation

and you add the hot or humid conditions contributing to high density altitude

the result may be that the aircraft is only capable of a controlled descent. (this is very frequently the case when weight loading issues are involved.)