I seem to remember two S61 gearboxes burning out. One on the North Sea and the other an SAR machine. Engine run down and settling onto the back of a supply boat. A calm sea state was regarded as a good 61 ditching day.
The S76 threw a blade at Aberdeen and we flew next day with tie wraps holding the blade bearings in. When the turbines started bursting a ring of armour plate was placed around them to stop them damaging the luggage.
The old Puma 330 had problems with pitch horn bearings, inclined shaft hinges and a fatal at Aberdeen where an engine run down when the other was pulled back for training.
For the inaugural flight of the 234 they placed tea and biccies for the passengers, there being a cabin attendant. At the appointed time the locker was opened and there was a sea of writhing crumbs. Again a calm sea was 234 water taxiing time to get to the Shetland basin. A 234 was also responsible for the greatest loss of life.
The 332 started going through gearboxes like a lottery winner. There must have been three in the air at the same time in the hangar. Rotor heads cracking offshore, innumerable spurious fire warnings and again an inclined shaft hinge pin coming out. It took about two years to solve all the problems.
Alan Bristow, an ex test pilot, used to create at the helicopters companies because he did not know why the users had to do all the advanced test flying for them; this covered all companies.
It happened so often in those days that it didn't make the papers.