A twin engine plane is designed to fly safely on one engine. This is because at cruise, a plane only uses about 15% of available engine power (from each engine), or in the case of a single engine, 30%, the rudders making up for the yaw moment from the thrust differential. Similarly, it can land with one engine as well, because lets be honest, how often do you land a plane at full throttle? But, if an engine unexpectedly shuts down/falls off/explodes during takeoff, with no rudder deflection, the aircraft will very quickly yaw and roll to the side of the unpowered engine, and pitch downward. The resulting dive is dangerous because, not only is the plane suddenly moving rapidly toward the ground, but also, since the plane is canted to the side, not all of the lift produced by the pilot pulling back on the stick is converted into upward rotation (some of it causes the airplane to move horizontally). Thus, it takes a lot more elevator deflection from a possibly damaged hydraulic system to right the aircraft. When you're only 1000 ft off the ground, the result is what happened today.

As far as differences in aircraft design go, it really doesn't come significantly into play on a twinjet in this situation. Any two engine aircraft (engines mounted mid-wing) will exhibit these dynamics if it is faced with a catastrophic engine failure while at high power. Design mainly comes into play when dealing with the less severe scenario of a catastrophic engine failure while at cruise altitude and power.

And to think I was lurking here to take a break from my aero homework .

Edited to add content.

[This message has been edited by terradevil (edited 11-12-2001).]