All aircraft systems and components could suffer random failures or be adversely affected by maintenance or other interventions
so much of our trust is with the maintenance people
As drivers you place faith in the system, and that it works as it should.
Had to winch a pilot and his pax out of the water after a ditching because of vibrations (helo). Turned out a component in the rotor head, which had been installed as a new item, obtained from the manufactures distribution centre, was actually time expired and should have been scrapped, but somehow made its way back into the supply chain.
Called early one morning to do a medevac in a helo. The routine was that the aircraft had been pre flighted, prepped etc the previous day, so all the responding crew had to do was pull the bungs, a quick walk around, and get the show on the road. In flight the aircraft had a bit of a vibe and was written up on return. Engineering inspection found that bearings had not been installed on any of the rotor blades. The only way that that was evident was a black powder emanating from where the bearings should have been, the black powder being the result of flying/operating. Without the black powder as a clue you would have had no idea the bearings were missing. So many questions to be asked, duplicate inspections on build up of the rotor head, vibrations during the blade tracking and test flight, pre flight during the prep for the medevac duty - was powder evident? Don't know any of the answers found. And it was not a shoddy organisation when it came to maintenance, quite the reverse in fact, but it highlights how fallible we humans are, or can be.