Expert: Paul Soderman - 11/16/2004

Question
A friend and I were commenting the other day how it is very rare to hear about an airliner gliding into a safe (or at least survivable), landing on land or water.  Especially since WWII bombers did so on a fairly regular basis.

My question is how would an aircraft fare during an unpowered landing, both on land and water, if the underwing engines were ejected by some means?

My belief is that gliding range would increase dramatically (due to loss of drag and weight), and water landings would be safer to attempt (less chance of the engine hitting the water and cartwheeling the plane).

Thank you for your time.

Answer
Hi Ed

Fortunately, unpowered landings of commercial transport are rare nowadays because of the redundancy in the power plants.  Which is good because they don't glide very well as you suspect.  Large aircraft are really heavy and tend to glide like a rock.  I recall a crash landing off the coast of Africa a few years ago caused by a hijacking and the plane basically came apart.  There were  survivors, but barely.  As for ejecting the engines over water, that would help avoid the nose down moment, but the means of safely disconnecting the fuel lines and other services just before a crash and never doing it accidently in flight, would add a complication that would be difficult to sell to Boeing, I would think.  Plus, the other problem is that with low wing aircraft one wing tip usually hits the water before the other and if speed is sufficient, the plane will still cartwheel or yaw violently.  I suppose the high wing bombers of WWII bled off enough speed before the wing tips hit.  Over land, ejecting engines to improve gliding would require a certainty that no one on the ground would be clobbered by the engines.

Sorry Ed, your idea has merit under a narrow set of conditions, but would be very difficult to implement for all conditions it seems to me.

Paul