[Thermalseeker]

By rights any IR guided missile would have hit an engine or wing.

The 747 has 5 engines. Don't forget the APU in the tail. It's a little turbine engine that powers the on board systems. You can see the tailpipe of the APU at the rear of a 747 fuselage. Most big jets have one.....

[Non-Sequitur]

The 747 has 5 engines. Don't forget the APU in the tail. It's a little turbine engine that powers the on board systems. You can see the tailpipe of the APU at the rear of a 747 fuselage. Most big jets have one.....

APUs are used on the ground to provide power when the four main engines are shut down. Hence the name APU - Auxiliary Power Unit.