Airworthiness Directive · Amendment 39-21025 · Sikorsky Aircraft Corporation Helicopters
Sikorsky Aircraft Corporation Helicopters
This AD applies to Model S-70, S-70A, S-70C, S-70C(M), and S-70C(M1) helicopters, certificated in any category, with a tail rotor (T/R) blade part number 70101-31000 (all dash numbers) with a serial number (S/N) up to and including A009-08915.
Note 1 to paragraph (c) of this AD: Each T/R blade is marked with the S/N.
The FAA is adopting a new airworthiness directive (AD) for certain Sikorsky Aircraft Corporation (Sikorsky) Model S-70, S-70A, S- 70C, S-70C(M), and S-70C(M1) helicopters. This AD was prompted by four incidents of disbonding between the tail rotor (T/R) blade pitch horn and the torque tube. This AD requires recurring visual and tap inspections of the T/R blade, and depending on the outcome, replacing the T/R blade. The FAA is issuing this AD to address the unsafe condition on these products.
Before the first flight of each day:
(1) Visually inspect each T/R blade for a crack, leading edge erosion, and trailing edge skin disbonding and separation, paying particular attention to the area from the midspan to the pitch control horn. If there is a crack, any leading edge erosion, trailing edge disbonding, or trailing edge separation, before further flight, replace the T/R blade with an airworthy part.
(2) Tap test inspect each T/R blade for disbonding in the pitch horn to torque tube bond area. If there is any disbonding, before further flight, replace the T/R blade with an airworthy part.
