AD 2021-15-52 Prompted By A Fatal Accident In Which An Outboard Main Rotor Hub Strap Pin (Pin) Sheared Off During Flight

The FAA is adopting a new airworthiness directive (AD) for various restricted category helicopters originally manufactured by Bell Textron Inc.

This AD was prompted by a fatal accident in which an outboard main rotor hub strap pin (pin) sheared off during flight, resulting in the main rotor blade and the main rotor head detaching from the helicopter. This AD requires removing certain pins from service and prohibits installing those pins on any helicopter. The FAA previously sent an emergency AD to all known U.S. owners and operators of these restricted category helicopters and is now issuing this AD to address the unsafe condition on these products. This AD is effective August 13, 2021. Emergency 2021-15-52, issued on July 8, 2021,

Supplementary Information: On July 6, 2021, the FAA issued Emergency AD 2021-15-51 (Emergency AD 2021-15-51) for Bell Textron Inc. Model 204B, 205A, 205A-1, 205B, and 212 helicopters. That action was prompted by a Bell Textron Inc., Model 212 helicopter fatal accident in which a pin part number (P/N) 204-012-104-005 with a serial number (S/N) prefix “FNFS” sheared off during flight, resulting in the main rotor blade and the main rotor head detaching from the helicopter. The pin had accumulated only 20 total hours time-in-service (TIS). An inspection of a different Model 212 helicopter revealed that another pin installed, and made by the same manufacturer with the same S/N prefix, was deformed; this pin had accumulated only 29 total hours TIS. Failure of the pin could result in the main rotor blade detaching from the helicopter and subsequent loss of control of the helicopter.

Transport Canada, which is the aviation authority for Canada, has issued Canadian Emergency AD CF-2021-23, dated July 5, 2021 (Transport Canada Emergency AD CF-2021-23), to correct an unsafe condition for Bell Helicopter Textron Inc., Model 204B helicopters, S/Ns 2001 through 2070 and 2196 through 2199; Model 205A-1 helicopters, S/Ns 30001 through 30065, 30067 through 30165, 30167 through 30187, 30189 through 30296, and 30298 through 30332; Model 205B helicopters, S/Ns 30066, 30166, 30188, and 30297; and Model 212 helicopters, S/Ns 30501 through 30999, 31101 through 31311, 32101 through 32142, and 35001 through 35103. Transport Canada advises that during an investigation of a Bell Textron Inc., Model 212 fatal accident in Canada, it was discovered that a pin P/N 204-012-104-005 with an S/N prefix “FNFS”, sheared off during flight, leading to detachment of the main rotor blade and the main rotor head. The pin had accumulated only 20 hours of service, and inspection of another Canadian Bell Textron Inc., Model 212 helicopter found a pin of the same P/N, made by the same manufacturer, with the same S/N prefix “FNFS”, to be deformed after only approximately 29 hours in service. According to Transport Canada, failure of a pin will result in detachment of the main rotor blade and loss of control of the helicopter.

Transport Canada also advises that, although the defective pins were only reported on Bell Textron Inc., Model 212 helicopters, pins of the same P/N can also be installed on Bell Textron Inc., Model 204B, 205A1, and 205B helicopters. While the cause of failure has not been determined, as a precautionary measure and to address the risk of detachment of affected pins in flight, Bell has issued alert service bulletins that specify replacing pins P/N 204-012-104-005 that have S/N prefix “FNFS”.

Accordingly, Transport Canada Emergency AD CF-2021-23 requires replacement of affected pins. Transport Canada considers its emergency AD an interim action and states that further AD action may follow.

After Emergency AD 2021-15-51 was issued, the FAA determined that pin P/N 204-012-104-005 with S/N prefix “FNFS” could also be installed on restricted category helicopters originally manufactured by Bell Textron Inc. These helicopters include, but are not limited to, the following:

• Rotorcraft Development Corporation Model HH-1K helicopters;
• Robinson Air Crane Inc.; Rotorcraft Development Corporation; and Tamarack Helicopters, Inc., Model TH-1F helicopters;
• Bell Textron Inc.; Overseas Aircraft Support, Inc. (type certificate previously held by JTBAM, Inc.); and Rotorcraft Development Corporation Model TH-1L helicopters;
• Richards Heavylift Helo, Inc., Model UH-1A helicopters;
• International Helicopters, Inc.; Overseas Aircraft Support, Inc.; Red Tail Flying Services, LLC; Richards Heavylift Helo, Inc.; Rotorcraft Development Corporation; Southwest Florida Aviation International, Inc. (helicopters with an SW204 or SW204HP designation are Southwest Florida Aviation International, Inc., Model UH-1B helicopters); and WSH, LLC (type certificate previously held by San Joaquin Helicopters), Model UH-1B helicopters;
• Bell Textron Inc.; Overseas Aircraft Support, Inc.; Rotorcraft Development Corporation; Smith Helicopters; and West Coast Fabrications Model UH-1E helicopters;
• AST, Inc.; California Department of Forestry; Robinson Air Crane, Inc.; Rotorcraft Development Corporation; and Tamarack Helicopters, Inc., Model UH-1F helicopters;
• Arrow Falcon Exporters Inc.; Global Helicopter Technology, Inc.; Hagglund Helicopters, LLC; JJASPP Engineering Services, LLC; Northwest Rotorcraft, LLC; Overseas Aircraft Support, Inc.; Richards Heavylift Helo, Inc.; Rotorcraft Development Corporation; Southwest Florida Aviation International, Inc. (helicopters with an SW205 designation are Southwest Florida Aviation International, Inc., Model UH-1H helicopters); and Tamarack Helicopters, Inc., Model UH-1H helicopters;
• Bell Textron Inc.; Overseas Aircraft Support, Inc.; and Rotorcraft Development Corporation Model UH-1L helicopters; and
• Robinson Air Crane, Inc.; and Rotorcraft Development Corporation Model UH-1P helicopters.

Therefore, the FAA issued Emergency AD 2021-15-52 to address the unsafe condition on these helicopters. Emergency AD 2021-15-52 requires removing the affected pins from service and prohibits installing those pins on any helicopter. The FAA sent the emergency AD to all known U.S. owners and operators of these helicopters

FMI: www.regulations.gov