AD 2023-2232 Was Prompted By Reports Of Helicopters Losing A Tail Rotor Blade (TRB) Tip Cap

The FAA proposes to adopt a new airworthiness directive (AD) for certain Robinson Helicopter Company Model R22, R22 Alpha, R22 Beta, R22 Mariner, R44, R44 II, and R66 helicopters.

This proposed AD was prompted by reports of helicopters losing a tail rotor blade (TRB) tip cap. This proposed AD would require visually checking and inspecting certain part-numbered and serial-numbered TRB tip caps for evidence of corrosion and, depending on the results, removing the corrosion. This proposed AD would also require removing all affected TRBs from service and prohibit installing them on any helicopter. The FAA is proposing this AD to address the unsafe condition on these products. The FAA must receive comments on this proposed AD by January 22, 2024.

The FAA has received three reports of TRB tip caps coming loose due to corrosion at the bond on Robinson Helicopter Company Model R44 helicopters. Due to the similarity of the TRB tip caps on Robinson Helicopter Company Model R22, R22 Alpha, R22 Beta, R22 Mariner, R44 II, and R66 helicopters, those model helicopters are also affected by this issue.

According to Robinson Helicopter Company, it has also seen TRBs that have corroded to an unserviceable condition, including severe leading edge pitting and degradation of the bond at the tip cap. Robinson Helicopter Company advises that helicopters operating near saltwater are particularly susceptible to corrosion, especially if stored outdoors. Affected TRBs were factory-installed or shipped as spares prior to November 2022. The three reports include a TRB tip cap departing its helicopter. The separate incidents occurred during a run-up check, after landing, and during a landing on different helicopters. Accordingly, this proposed AD would require repetitively checking and inspecting the tips caps of TRB part number (P/N) A029–2 with TRB serial numbers (S/N) up to 11279 inclusive (P/N A029–2 REV A through U inclusive), TRB P/N C029–3 with TRB S/N up to 14329 inclusive (P/N C029–3 REV A through Q inclusive), and TRB P/N F029–1 with TRB S/N up to 3099 inclusive (P/N F029–1 REV A through F inclusive) for evidence of corrosion, removing corrosion, and eventual removal of those TRBs from service.

A debonded TRB tip cap can cause severe vibration and possible failure of the tail rotor gearbox housing. This condition, if not addressed, could result in increased vibrations, reduced controllability, and subsequent loss of control of the helicopter.

FMI: www.regulations.gov