I'm assuming that the tail rotor drive pinion is normally lubricated by the MGB lube oil system. Is this a known weak point in this type of MGB design?
As for the flotation collars not working, I'm assuming that the rate of descent and high G forces may have played a part there. The fact that the pilots were attempting an auto-rotation due to tail rotor failure and got their speed below 85 knots to arm the flotation system just re-enforces that they were doing their best with what they could and by the book.
What's still bugging me is why were they flying at 800 feet and 133 knots when they knew that the MGB lube oil system was compromised? What height would you have to be at to ensure that an auto-rotation operation could be implemented effectively? Was the lube oil temperature reading falsely low, and until the tail rotor drive failed they had no knowledge of anything else amiss that would warrant going from land as soon as possible to land immediately? Has the RFM been fully updated to ensure that this cannot happen again?
Going forward, would it not make sense to have temperature sensors at all critical points in the MGB? These could then pick up excessive heat build-up and force a land immediately action as well as lube oil pressure < 5psi. The only other options are to have either an ELS and/or more robust MGB components to achieve a true dry-run capability. I wonder what the CH-148 new MGB design is going to be...
Last edited by maxwelg2; 18th Jun 2009 at 21:37.