A story is told of daze of old. The Tail Rotor Drive Shaft Cover on the 42 degree vertical fin of a 205 or 212 being left unfastened. It flipped open during landing at a location to drop some pax. As the helicopter accelerated after departure the now open cover caused a very pronounced nose up attitude and the cyclic rapidly ran out of forward travel until the nose up attitude slowed the aircraft. Then the nose went back down and the aircraft accelerated again and up went the nose..this oscillation went on for a few cycles until order was restored. The helicopter was landed ASAP, shut down and there was considerable in the way of swearing and cursing. Fortunately the pilot and pax quickly cut some trees down ( it helps to be flying survey crews equipped with chain saws, axes and bush savvy ) and improvised a ladder to get up and securely fasten the cowling. A rather detailed walk-around was conducted before departing.

She was lucky. A colleague working on a car (not chopper related, I know) put his hand in the engine bay, wedding ring bridged between a 12V contact and engine block, in a few seconds it cauterized the blood supply; he lost the finger. Since hearing this I remove my wedding ring when doing work like this.

During an annual inspection last year I discovered (through oil analysis) that my main rotor trans was making metal. ****….. pulled it out and sent it off. A year later a brand new trans finally shows up. I install it go for an hour long hovering test flight.

Lose the tail rotor…double ****.

bent the landing gear and broke the bubble on surprisingly good landing. Turns out that some idiot not only didn’t refill the oil in the tail rotor gearbox a year ago, but same idiot didn’t catch it on the preflight.

I now use/recommend a U-V flashlight for all sight glass inspections.

Metal watch strap will do the same for you.
Rings have been a known hazard for years.
The military safety poster from 40 years ago showing all the tendons torn out of the hand and arm when a ring had caught on a projection.
sticks in the mind!!!!

During my days in the National Guard flying Hueys and Kiowas.....30th Infantry Division Policy was no Rings allowed...and was strictly enforced due to far too many lost fingers

Old Chum of mine was missing one of his fingers due to his wedding ring getting trapped inside an aircraft step (the kind with the spring operated push in door) when he slipped and fell.

Leave those Rings at home.....plus for you geographical bacherlors or bachelorettes. over time that finger will gain an all over sun tan and ease your risk of getting rumbled while in pursuit.

Sight glasses are notorious on engines and gearboxes.
Got called out to a police BO 105 which was suffering from low engine oil pressure.
An initial look at the tanks appeared to show oil levels normal.
A closer look showed a full tank for one engine and a "tide mark" for the second.
A look into the tank confirmed no oil.

Yes, an AAC Lynx was lost in Germany for that reason.

AS365C1 TRGB in Oz for the same reason - "tide mark" - until it finally gave up gracefully.

Sight glasses can give you information other than the level.

On two occasions a colour change from light to dark lead to internal problems in Hughes 500 main gearboxes.
Metal in the oil that was not picked up by the chip plugs.

On another occasion the sight glass of an AS350 looked like a golden snow globe with particles glittering in the oil..
Another non ferrous internal failure not picked up by chip plugs.

Blakmax, I've PM'd you, can you give me a call please, or an email, been a while, have some questions for your talents.

Collected our police squirrel post heavy maintenance, it hadn't long been resprayed to the new blue and yellow.scheme. Ambled out and contrary to my usual somnolent walkround immediately spotted the black plastic TRGB cap on the dark blue horizontal stabiliser, the panel over the TRGB was secured. I've often wondered how far we would have got.....