Another one.
With one passenger I was flying my Bell 206L a hundred miles out in the Gulf of Mexico.
Just cruising along, when the helicopter suddenly shook violently for a split second.
The passenger, white faced, said, WHAT THE **** WAS THAT!
I said, "Damned if I know, but we are landing on 323. (the closest platform about 6 minutes away).
We arrived and landed without anything more happening.
I called "Roving Maintenance".
A PHI pilot mechanic and mechanic, that flies offshore working on any helicopter problems that pop up during the day.
The mechanic looked the bird over good but could not find any problem.
He told me to run the bird up, while he looked for any problems.
About the time I got the engine up to 100% the mechanic came running around the front of the helicopter yelling, "SHUT IT DOWN, SHUT IT DOWN!
I yelled, as I shut the engine down, "What the hell's wrong?
He said, "Number 2 tail rotor driveshaft bearing is GONE!
I said, "What the hell do you mean, ""GONE". It can't be Gone? The tailboon would be chopped off".
(That bearing is the second tail rotor drive shaft bearing supporting the tail rotor drive shaft that goes from under the engine back to the Tail Rotor. The shaft is spinning at a high RPM.
Unsupported the shaft would part and cut off the tailbone like a saw.
The Helicopter would go inverted and spin down to crash (killing everyone onboard).
He said, "The inner and outer bearing race is still there but all the bearings are gone. (Leaving the t/r driveshaft unsupported and spinning at thousands of RPM. )
About that time it dawned on me, that I had flown about six minutes, during which it was impossible for the spinning tail rotor drive shaft to NOT cut off the tail boom and kill us.
I went down to the Galley, where the passenger was having a Coffee, and told him what happened. And that it was "impossible" for the helicopter to still be flying after that bearing failed.
I told him, from today on, you are living on borrowed time. There is no reason that we weren't killed today.