914 owners - gearbox slipper clutch recall

[slb]

NEW RELEASE

 

MANDATORY ROTAX SERVICE BULLETIN:

 

"Replacement of the overload clutch of 914 (series)"

 

SB-914-050 / SB-914-050UL

 

ATTENTION ROTAX 914 OWNERS,

 

A GEARBOX SLIPPER CLUTCH RECALL

 

MAY AFFECT YOUR ENGINE!

 

Due to a deviation in the manufacturing process, certain ROTAX 914 series engines with optional gearbox overload clutches may be prone to unwanted slippage. Such a condition could lead to an over-rev of the engine during high power settings. The service bulletins SB-914-050 and SB-914-050UL describe the range of engine serial numbers known to be affected. Even so, not all the engines with affected serial numbers necessarily include an optional slipper clutch. To verify if your 914 engine has a slipper clutch that might be affected by this SB, a simple test can be performed by locking the crankshaft and checking for 30 degrees of free play prop movement (non slipper versions have no prop free play movement). For more information on testing your gearbox for inclusion of a slipper clutch, see this video.

 

The SBs also define a range of gearbox serial numbers which may be affected. As with engines, not all gear boxes with affected serial numbers necessarily include a slipper clutch, therefore the same verification test can be performed by locking the crankshaft and checking for 30 degrees of free play prop movement.

 

Also affected by this SB are any engine in which a clutch has been replaced or installed in the gearbox between November 1st 2014 and May 13th 2015 during general maintenance or overhaul.

 

This is a MANDATORY service bulletin, and replacement of the overload clutch on affected engines must be accomplished at the next BRP maintenance event or within the next 25 hours of operation, but at the very latest by November 9th, 2015.

 

IF you suspect a slipping clutch (observation of engine speed increasing without a corresponding increase in propeller speed) then the replacement must be carried out BEFORE THE NEXT FLIGHT.

 

For affected new engines not yet installed in an aircraft or yet to perform first start up, the bulletin must be carried out before first engine run.

 

Whenever conditions have resulted in the maximum engine speed or boost pressure being exceeded, the events must be recorded in the engine logbook as specified in the 914 Operator’s Manual section 4.2 and the ‘Overload Clutch breakaway torque measurement’ procedure should be performed, as described in the 914 Line Maintenance Manual chapter 05-50-00. The breakaway torque measurement usually requires the gearbox to be removed and mounted to a solid attachment. For further information on correct procedures for removal of the gearbox, see the following video.