73-12-06 GRUMMAN: Amdt. 39-1657. Applies to Grumman Models G-21 and G-21A Type Airplanes (Army OA-9, Navy, JRF-1 through JRF-6B under TC654) certificated in all categories.
Compliance required as indicated:
1. To prevent hazards in flight associated with the failure of the elevator torque tube assembly P/N 12755, rudder torque tube assembly P/N 12756, L.H. and R.H. rudder pedal torque tube assemblies P/N's 12757, 12758 and hinge support assembly P/N 12725, located below the cockpit floor, visually inspect these assemblies for cracks and corrosion within one month after the effective date of this A.D. unless already accomplished within the last eleven months and thereafter at intervals not to exceed twelve months in service from the last inspection.
2. On assemblies having 3000 hours or more time in service or exceeding 36 months in service, within one month's time in service after the effective date of this A.D. unless already accomplished within the last 23 monthsand thereafter at intervals of 2000 hours in service but not exceeding 24 months in service, remove and disassemble the elevator torque tube assembly P/N 12755, rudder torque tube assembly P/N 12756, the L.H. and R.H. rudder pedal torque tube assembly P/N's 12757 and 12758, and hinge support assembly P/N 12725. Inspect all parts for corrosion or cracks, using visual and dye penetrant or magnaflux inspection methods.
3. Before further flight, repair or replace corroded parts and replace cracked parts with new parts or with a used part inspected in accordance with this AD or with an equivalent part approved by the Chief, Engineering and Manufacturing Branch, FAA, Southern Region, except that the aircraft may be flown in accordance with FAR 21.197.
4. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Southern Region, may adjust the repetitive inspection interval specified in this AD.
This AD supersedes AD 72-13-05.
This amendment is effective June 14, 1973.