I have had 6 single engine failures on the S61N and one on the Super Puma L1. Of the 6 engine failures on the S61N, five came without warning. Only one had warning when in a straight and level flight the fuel shut off valve closed by itself electrically(physically it is in the OPEN position). Until today Sikorsky could not explain why it happened as the valve is to remain in its last energised position. The engine flamed out about 30 sec later.
On the Super Puma L1, the lady whispered "fuel" followed by both booster pumps failed light on one of the engines.We still had plenty of fuel in the tank. Again within a short while the donk failed. Later I found that one of the pipe lines from the tank to the engine had came loose and disconnected!