SDR 97ZZZX2476

Service difficulty report · Main Shaft · Skrsky S64F

Difficulty date
February 9, 1997
Submitted
March 26, 2000
Operation
General aviation
Filed by
JYDR439F
Erickson Incorporated
Aircraft
N158AC
Make and model
Skrsky S64F
Aircraft serial
64081
Part
Main Shaft
Part number
643520536101
Condition
Cracked
Location
Mgb Splines
Part time
2,969 hours
Component
643520500048
Stage of operation
IN
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

DURING O/H OF MGB, THE MAIN SHAFT WAS SUBJECTED TO A FMPI. ONE SPLINE FOUND CRACKED ACROSS THE SPLINE WIDTH ON UPPER END OF LOWER SPLINE. THE CRACK DID NOT APPEAR TO ORIGINATE WHERE THE LOWER PLANETARY SPLINE CONTACTS THE SHAFT, BUT WAS LOCATED APPROX 0.100 INCH ABOVE PLANETARY PLATE SPLINE CONTACT ZONE. THE CRACK EXTENDED FROM ROOF OF ONE SPLINE TOOTH TO THE ROOT OF ADJACENT SPLINE. APPROX 30 ADDITIONAL SPLINES HAD UNUSUAL CRACK-LIKE INDICATIONS IN ROOT RADIUS OF THE SPLINES. THESE INDICATIONS COULD NOT BE VERIFIED TO BE THE START OF CRACK. THE S HAFT IS BEING SENT TO A LAB FOR DESTRUCTIVE ANALYSIS OF THE CRACK AND ALL INDIC ATIONS. NOTE: THIS MDR PREVIOUSLY SUBMITTED, BUT INFO HAS BEEN CORRECTED.