77-0355 —

And the 135 just keeps flying and flying regardless of what you call it.

It does, but these smoke trails sure speak volumes of engine's efficiency.

You would think that the US military would have replaced the engines with new efficient fan motors…

AFAIK, E3 versions for Saudi Arabia and some other customers use newer turbofans, giving them better efficiency, longer loiter times and higher cruise altitude (translating into longer detection ranges for radar). I wonder why USAF cannot afford the same upgrade for theirs.

It looks like there is a black bomb on top, ready to be dropped somewhere!