Well, Rram, they don't really. However......:
A-10 has the engines mounted above the tailplane to shield them from enemy fire as well as making the engine exhaust a worse infra-red source from below. It can easily be flown on one engine, but damage/failiure to both engines will naturally bring it down, - for that it is designed to be a forgiving belly lander.
Now a brand new design, The SU-32:
"The crew¹s cabin has been designed in the shape of a single titanium bronze capsule, the construction of which was perfected on an Su-25 low-flying attack aircraft. There is defensive armour on the fuel tank, the engines and other vitally important parts of the aircraft. "
Speaking of SU's, the SU25 "Frogfoot" has engine armament and is known to have suvived hits from stinger missiles.
Now the F16 and the F15 are no close support aircraft, so a totally different design. They rarely return from a mission with bullet holes. In a dogfight however, they could be hit, presumably from the high 6, where the F15's entire wing section is over the engines, and the Fuselage of the F16.
hmmm, Rram, I don't know.
