Service difficulty report · Bearing · Airtrc AT502B

Difficulty date
October 5, 2023
Submitted
October 5, 2023
Operation
General aviation
Aircraft
N5197X
Make and model
Airtrc AT502B
Aircraft serial
502B0571
Aircraft time
9,040 hours
Propeller
Hartzl HCB4TN3
Part
Bearing
Part number
B61442
Condition
Cracked
Location
Propeller
Part time
3,043 hours
Component
Propeller · Hartzl · HCB4TN3
Component part number
HCB4TN3
Stage of operation
UK
How discovered
O
Nature of condition
O
Precautionary procedure
O

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

What was found

PROP ORIGINALLY REMOVED FOR ISSUES WITH PROP NOT FULLY CYCLING THROUGH ITS FULL RANGE OF MOTION. HAD ONE BLADE THAT WAS NOT ACTUATING PROPERLY. WAS TAKING LONGER THAN NORMAL TO GO TO FEATHER. PROP WAS DELIVERED TO NORTHWEST PROPELLER SERVICE FOR OVERHAUL. BEGAN DISASSEMBLY AND DISCONNECTED LINK ARMS. FOUND BLADE 3 WOULD NOT ROTATE FREELY AND APPEARED TO RATCHET. THE OTHER 3 BLADES APPEARED TO ROTATE NORMALLY. WHILE DISASSEMBLING BLADE CLAMPS FOUND 1 A-321 CLAMP SCREW WAS LOSE ON ONE OF THE OTHER CLAMPS AND THE LEADING EDGE SCREW ON BLADE 3 WAS EXCESSIVELY TIGHT. UPON FURTHER DISASSEMBLY THE FOLLOWING OBSERVATIONS WERE MADE: BLADE 3 HAS BROKEN BALL BEARING AND BEARING RACE FRACTURED AND IN NUMEROUS PIECES. BLADE CLAMPS SHOW EXTENSIVE DAMAGE. BLADE 1 HAS BROKEN BALL BEARINGS AND THE RACE WAS CRACKED. BLADE 1 BLADE CLAMPS SHOW DAMAGE BUT THE OTHER TWO BLADES HAVE SOME DAMAGED AND CRACKED BEARINGS WITH OBVIOUS BRINELLING ON THE BEARING RACES. BLADE 2 AND 4 BLADE CLAMPS DO NOT APPEAR TO HAVE ANY DAMAGE. BLADE 3 HUB ARM IS DAMAGED BEYOND LIMITS AND THE HUB IS SCRAP DUE TO BEARING RETAINER, WHICH APPEARS TO HAVE BEEN SPINNING IN THE CLAMP AS WELL AS DAMAGE FROM THE BROKEN BEARINGS. HARTZELL HAS BEEN NOTIFIED.