Service difficulty report · Grip · Tandem CH47DTAN

Difficulty date
February 6, 2024
Submitted
February 6, 2024
Operation
General aviation
Aircraft
N949CH
Make and model
Tandem CH47DTAN
Aircraft serial
900205
Aircraft time
10,523 hours, 7,013 cycles
Part
Grip
Part number
145R207516
Part serial
AM362
Condition
Cracked
Location
Aft Rotor Head A
Part time
4,332 hours
Component
Aft Rotor Head
Component part number
145R200420
Stage of operation
FF
How discovered
V
Nature of condition
Z, P
Precautionary procedure
K

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

What was found

A CRACK WAS FOUND ON THE AFT ROTOR HEAD, RED PITCH HOUSING (GRIP) PART NO.:145R2075-16, SERIAL NO.: AM362 LOCATED FROM THE EDGE OF THE PITCH HOUSING DAMPER ATTACHMENT UPPER LUG, TRAVELING PAST THE BUSHING FOR THE DAMPER ATTACHMENT BOLT FURTHER INTO THE PITCH HOUSING CASTING. THIS WAS FOUND DURING DAILY MAINTENANCE INSPECTION BY ONSITE MX STAFF AT THE END OF THE FLIGHT DAY. AFT ROTOR HEAD ASSEMBLY WAS REMOVED FROM SERVICE AND REPLACED WITH A SERVICEABLE ASSEMBLY. NO DEFECTS WERE NOTED TO THE DAMPER OR ANY OTHER ATTACHING PARTS. AFFECTED AFT ROTOR HEAD ASSY. TO INCLUDE AFFECTED PITCH HOUSING WAS OVERHAULED AND RETURNED TO SERVICE ON 9/24/2021. DURING THE OVERHAUL PROCESS THE UPPER BUSHING LOCATED NEAR THE CRACK WAS VISUALLY INSPECTED AND DIMENSIONALLY INSPECTED AND CHECKED PER THE OH MANUAL. FLUORESCENT PENETRANT NDT PROCESS WAS ALSO ACCOMPLISHED AT THIS TIME. THE DAMAGED AFT ROTOR HEAD ASSY. WAS ORIGINALLY INSTALLED ON 2/28/2023. THIS AIRCRAFT IS CURRENTLY OPERATING IN CHILE ON A FIRE CONTRACT.