Originally Posted by
DaveReidUK
For the 737NG for example, Boeing quotes a danger zone defined as a 10 foot arc centred on the CFM56 nose cone at ground idle and 14 feet at higher power settings.
There are few, if any points within those arcs where the existing beacons aren't visible.
A beacon/light on the engine intake might make the association of "This Engine is Engine Running" more obvious. The ground staff rushing to open cargo doors adjacent to a still running Engine #2 in a common scenario. Rush Rush is the culture of LoCost Travel and contracted airport providers.
It's also more polite than my first idea which was a neon light next to the aircraft cargo door flashing "F##k Off Suicidal Tw#t"!