SDR CA010503015

Service difficulty report · Shaft · Skrsky S76C

Difficulty date: March 23, 2001
Submitted: May 11, 2001
Operation: General aviation
Make and model: Skrsky S76C
Aircraft time: 1,204 hours
Engine: Tmeca ARRIEL2B
System (JASC): 2421 · AC Generator-Alternator
Part: Shaft
Part number: 31176002
Condition: Worn
Location: Generator
Stage of operation: IN
How discovered: V
Nature of condition: O
Precautionary procedure: K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

(CAN) AIRCRAFT GENERATOR TURNS AT 12,000 RPM IS DRIVEN BY THE MAIN TRANSMISSION OF HELICOPTER & FAN CAME LOOSE ON SHAFT, RETENTION NUT MS21042-4 HAD SELF LOCKING FRICTION STILL WITHIN LIMITS. FAN IS A FIT ON SHAFT BY NUT TORQUE ONLY, NUT MUST NOT HAVE BEEN ON TIGHT ENOUGH, EVEN THOUGH NUT FRICTION WAS WITHIN LIMITS. FAN BEGAN TO VIBRATE AND A HIGH FREQUENCY VIBRATION WAS FELT. FAN COST IS US$4,900.00 FOR A SIMPLE FAN BLADE WITH REQUIRED AN EXCHANGE GENERATOR COST US$13,000.