One of the Warrant Officers in my AeroScout platoon (Army Air Cavalry) received his nickname because he decided to show the "new guy" (me) how cool it was to hover the OH-58 helicopter up underneath a particularly large cottonwood tree. I was on a "local area orientation flight" with him, so he was PIC. I kept telling him "This doesn't look like a good idea to me..." and "Have you done this before?" He kept insisting that it was in the unit SOP (standard operating procedures) to mask the helicopter as far as possible beneath the overhanging limbs because they made for very effective camouflage...
Yeah, there was sufficient clearance below the branches – right up to the point where the rotorwash began sucking them down. I started seeing chunks of leaves and small branches flying through the rotor system, and then "Whoomp!" An almost 6-inch diameter branch came crashing through the rotor system and literally exploded. For a few seconds there, we were IFR in a brown cloud of sawdust. We landed fairly hard – but seemingly level.
So, I'm sitting there with my hand on top of the collective lever (to prevent lifting off again), leaning on it with all my weight as Mr PIC is trying as hard as he can to get us airborne again so he can hover out from underneath the tree... I inform him that we're not going anywhere, no matter WHO is supposed to be the PIC for this mission. Landing = end of flight. PIC expires on the ground. I'm the senior officer, and we are NOT moving this helicopter until maintenance has performed the appropriate inspections.
Turns out there is no such SOP (gee, really?) and he was just trying to show off for the new guy, doing something he'd never done before but always thought would be really cool to try... What could possibly go wrong? Well, for starters, cottonwood trees are notoriously "brittle" and have a habit of dropping huge limbs periodically for no apparent reason. Add a hundred mile-per-hour rotor downwash to the equation, and the result was predictable – thus my earlier questioning of his decision.
As it turns out, he was really lucky I would not allow him to take off again... The large limb was apparently termite-infested and totally rotten. It left brown stains everywhere (apparently, including in our shorts!) but did little damage. The tail rotor blades, on the other hand, were not quite so lucky. Apparently, he wasn't quite as "level" as it appeared when we landed, or there was a hummock tall enough to be a problem, because both tail rotor blades were damaged enough to have to be replaced. The blade tips were basically ripped open, and they had dirt all over them – not the brown powdery stuff from the limb. Structurally, they were totally shot – you could flex and twist them with your bare hands.
At the time, I had one of those small Olympus tape recorders that I used on every flight, to record everything that came over the intercom. (I used the tiny earpiece plugged into the mike jack of the recorder, with the earpiece in the earcup of the flight helmet. It was a cheap solution, but it worked like a somewhat "tinny" microphone, recording everything that came through the intercom / radio system. It was a good thing I had it with me and turned on, because the guy tried to blame me, saying I was the one flying the helicopter. I just pulled out the tape recorder, and played back the entire discussion, all the way through to my "We're not moving this helicopter until maintenance clears it for flight" comment.
His new callsign? Well, his actual last name was "Good", so his new callsign became "NotSo"... The best part was explaining how he got it to every new guy in the unit...