The rear of an airplane both in the air and on the ground is a dangerous place. In the air you have to concern yourself with wake turbulance (not caused by the engines, but the wingtip vorticies). On the ground you have to worry about Jet and Prop blast.

This “danger zone” is different depending on the type (jet/prop) and size of the aircraft. Below is the areas around an airplane where jet blast is dangerous.

A diagram is also available.