Seems almost certainly a manufacturing defect of the shaft (AAIB says crack in the vicinity of a weld joining 2 halves of the shaft). I see EC now has a bulletin on TIPI indicating that there is a batch of suspect shafts - I believe a recent batch. Fortunately we don't have any of that batch on our fleet so we are not affected.
PCD - yes I noticed the wording as well, and of course they said some glycol was found in the MGB. There are 2 pressure switches, one for the bleed air and 1 for the glycol. After pressing the SHOT button, the system waits 20 secs and then expects both pressure switches to be showing pressure. If not, MGB EMLUBE illuminates and it is Land Immediately.
Trouble is those pressure switches are only activated with a real emergency or during maintenance, the rest of the time they do nothing except sit there and degrade. When we first got our fleet, the maintenance interval was 750 hrs and we routinely found 1 or other switches inop. We reduced the check to 375 hrs and I think we change them at 375 hrs(?). I am not sure whether this is our company procedure, or whether it is now manufacturer's procedure. In any case, chances are that the EMLUBE was working but they had indications of failure. In that respect it is a poorly designed system.
We just fleet checked the pressure switches and all ours were found to be working correctly.
This would explain oil leakage - with the engine bleed air pressurising the gearbox, oil is forced out of every orifice and low pressure seal making a right mess. (it has happened, though fortunately only on the ground!)
HC
Last edited by HeliComparator; 13th May 2012 at 13:52.