AD 2022-21-11 Requires Repetitive Inspections Of Each MRB

The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Inc. Model 204B, 205A, and 205A-1 helicopters and various restricted category helicopters.

This AD was prompted by a report of cracked main rotor blades (MRBs). This AD requires repetitive inspections of each MRB and removing any cracked MRB from service. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective November 16, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain serial-numbered Bell Textron Inc. Model 204B, 205A, and 205A-1 helicopters, and all restricted category Model HH-1K, SW205A-1, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters, with MRB part number (P/N) 204-011-250-001, -005, -009, -113, or -117 installed.

The NPRM published in the Federal Register on June 29, 2022 (87 FR 38686). The NPRM was prompted by reports of chordwise cracks in MRB P/N 204-011-250-113. The cracks originated from the extreme trailing edge between blade station 190 and 210; this area is currently not inspected during routine maintenance. In the NPRM, the FAA proposed to require cleaning certain areas of the upper and lower skin surfaces of each MRB with a cheesecloth. If the cheesecloth is snagged or frayed while cleaning an MRB, removing paint from the area that caused the snagging and then either visually or eddy current inspecting the area for a crack would be required. The NPRM also proposed to require wiping each MRB with isopropyl alcohol and immediately after the blade dries, inspecting the area for a dark line, which is an indication that excess alcohol is bleeding out of a crack or edge void. If there is a dark line, removing paint from the area where there is a dark line and inspecting for a crack in the skin would be required. Finally, the NPRM proposed to require removing any cracked MRB from service. The FAA is issuing this AD to address the unsafe condition on these products.

FMI: www.regulations.gov