Airworthiness Directive · Amendment 39-18759 · Tail rotor control system
Sikorsky Aircraft Corporation
This AD applies to Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters, certificated in any category, with a tail rotor pitch change shaft (TRPCS) assembly part number (P/N) 92358-06303-041 or P/N 92358-06303-042 with less than 80 hours time-in-service (TIS) installed, except those TRPCS assemblies manufactured or overhauled on or after November 3, 2016.
We are publishing a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters, which was sent previously to all known U.S. owners and operators of these helicopters. This AD requires inspecting certain bearings. This AD is prompted by a report of a failed bearing. We are issuing this AD to address the unsafe condition on these products.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) For TRPCS assemblies with less than 5 hours TIS since new or overhaul, before further flight, remove the TRPCS assembly from service.
(2) For TRPCS assemblies with between 5 and 15 hours TIS since new or overhaul, before further flight, and for TRPCS assemblies with more than 15 hours TIS, within 20 hours TIS or before reaching 80 hours TIS, whichever occurs first:
(i) Borescope inspect the TRPCS assembly as follows, unless done within the previous 15 hours TIS.
(A) On the TR side of the TRPCS bearing, remove the plug from the end of the TRPCS, insert the borescope into the TRPCS, and determine whether the white Teflon seal and snap ring are installed. If the white Teflon seal or snap ring is missing, or if there is a rip, tear, or heat damage on the seal or if there is no gap in the snap ring, before further flight replace the TRPCS assembly.
(B) On the TR servo side of the TRPCS bearing, insert the borescope through the oil filler cap hole and determine whether the white Teflon seal, snap ring, and cotter pin are installed. If the white Teflon seal, snap ring, or cotter pin is missing, if there is a rip, tear, or heat damage on the seal, or if there is no gap in the snap ring, before further flight replace the TRPCS assembly.
(ii) If the TRPCS assembly has less than 10 hours TIS, perform ground operation with the rotor turning at 105% (N r) until the TRPCS assembly has accumulated 10 hours TIS, cycling the TR control pedals at least 10 times per hour.
(iii) Remove the TRPCS and inspect the SB2310 angular contact bearing for free rotation, purged grease with metal particles, a nick or a dent, and any cut, tear, or distortion on the bearing seal. If the bearing does not rotate freely; the bearing sounds rough or chatters; there is any purged grease with metal particles; a nick or dent; or if there is a cut, tear, or distortion in the bearing seal, before further flight, replace the TRPCS assembly.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
