This one is for those of you that fly with Fenestrons.
Moons ago, in Norway, flew to a distant outpost in support of Infantry. It was a two day exercise. Weather lovely and sunny but this was only a benefit up on the mountain tops. Down in the valleys it was brass monkey cold. During the pre-flight the morning of day two I was busy clearing the snow off the fuselage and when at the Fenestron discovered that the fenestron blades were firmly stuck to the ducting by ice. Luckily I had by this stage not hand turned the main rotor blades nor of course started the rotors. So now, no matter what the weather, I always check that there is no debris in the fenestron - ice or otherwise before doing anything else.
This one was pure luck that I spotted it. Doing a walk round prior to flight one afternoon. This H300 had flown already that day and was still warm. As I scanned down the port skid something caught my eye. Something looked awkward/not quite as I was used to. Upon closer inspection I found that the skid was cracked radially just infront of the front upright and was at a slightly higher angle than normal. We were planned to do running take-off and landings as part of a limited power review. Didn't fly that machine. Another H300 on another day. Noticed that the locking wire was broken on the nut which hold the tail rotor drive shaft to the tail rotor drive and that the nut had backed off a good way.
I have a wonderful collection of mechanics tools as I believe that what I find hidden away after a Servicing is mine. Spanners under MRGB's are difficult to retrieve. The military have a stringent tool control system and I can say that none of my tools have come from that source.
Post engineering is perhaps the most critical time for all sorts of demons to lurk.
In most cases within the wording of the flight manuals is mention that on close down after flight one should listen for strange noises.
Had this been done by the previous pilot the fault I found during a pre-flight would have been discovered, snagged and the fault rectified. In the early 70ties I was doing my pre-flight on an Alouette 2 and swinging the rotor blade round found that I couldn't move the rotors round. Initially thinking that the rotor brake was locked in the 'ON' position, I returned to the cabin to release the brake. It was 'OFF'. The problem was that the MRGB was seized for some reason. I snagged the aircraft and signed out another for the flight.
I shudder when I see pilots walk up to their helicopter with nothing more than a cursory glance and fly away. I'm not that trusting.
Fuel caps left off by refuellers is a favourite.