I've probably spent more time then most here out on the ramp in very close proximity to engines running at full power, the diagrams of the safe zones given in the AMM can begin to seem overly cautious and complacency is likely to set in the more often a person is actually out there doing it. These days with FADEC the engines are almost plug and play with regards to rigging, but in the olden times we'd have to set limits for rpm and egt, accel and decel rates as well as just look for any fuel or oil leaks. I've been out at the blast fence for hours trying to get things dialed in. The adjustments require you to be hands on with the engine when it's running at T/O power often times while standing on a ladder. I'm guilty of having been complacent, I would normally use over ear hearing protection and rarely wear a baseball cap at work but one rainy day we were finishing up an engine change on a G-III and I didn't feel like getting my head wet so I put on a cap and quickly figured out it and my ear muffs weren't compatible so I switched to ear plugs and off we went to the blast fence. Adjusting a Spey engine requires a ladder and multiple trips from the engine to the cockpit so the person running the engine and the person adjusting it can communicate and ensure we're on the same page, we use the ailerons and speed brakes as references to fine tune things, but it normally involves a lot of running back and forth and it can become a bit tiresome. The fuel control on a Spey is mounted towards the front of the engine just a little aft of the trailing edge of the wing, I don't recall what adjustment I was making, probably accel/decel, and I decided to take a load off and have a seat on the trailing edge directly under the inlet rather than stand on the ladder. You can probably figure out where this story is going, as I felt the baseball cap start to get sucked off my head I had a few things run through it, first was the hat was going to hit the fan and then how much • would hit the fan when I got back to the hangar. I was young with ninja like reflexes and grabbed my hat as it was coming off and caught it, but I had my adjustment tool in the same hand and not only gave myself a nice lump but also a small cut on the top of my head. We got it all done and everything was okay but I'd certainly taught myself a lesson, those safety zones exist for a reason. Occasionally seeing the aforementioned pictures of wing mounted engines and what can happen when people aren't respecting those safety zones always reaffirms my sometimes overcautious approach. I have to add if someone here ever works on Gulfstreams you need to be outside of the airplane on the ground to see two things, stand at the nose safety position and watch one test accel/decel on each engine separately and look at one when it's at max diff on the ground, the cabin windows inflate about 3/4-1".
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