To highlight the dangers of working around running engines (be it Cessna 150 or A380)
I was told by an engineer at TFS: Apparently a ground run was going on (high speed run), one engineer under the engine (secured to the engine with a harness) and an engineer on the headset by the nose gear talking to the flight deck. The engineer under the engine signaled to the engineer on the headset to shut the engine down - the signal was not understood, so the engineer approached the engine from the side to speak to the person under the engine - the instruction was communicated, and the unfortunate engineer rather that walking sideways away from the engine walked forward. That one mistake near a prop or jet and it could be your last.