Emergency AD for Bell Choppers

A superseding Emergency Airworthiness Directive (AD) has been issued by the FAA to correct the applicability of Emergency AD 2009-07-51 issued on March 17, 2009. The Emergency AD requires, before further flight, inspecting each cyclic control lever assembly (lever assembly) to determine if it is correctly installed and properly staked in the lever assembly. Replacing any bearing that is incorrectly installed or improperly staked in the lever assembly is also required before further flight.

AD 2009-07-51 was prompted by a Transport Canada AD report of a bearing incorrectly installed in the copilot lever assembly. Investigation revealed that, although the inspection witness marks were applied on the bearing, it had not been properly staked during manufacture of the lever assembly. This condition, if not detected, could result in failure of a bearing, failure of a lever assembly, and subsequent loss of control of the helicopter.

Emergency AD 2009-07-51 applies to all Bell Model 206A series, 206B series, 206L series, 407, and 427 helicopters with a lever assembly, P/N 206-001-401-111, 206-001-400-115, 206-001-400-111, 407-001-320-105 or 407-001-320-109, installed.

Since the issuance of Emergency AD 2009-07-51, the FAA determined that it should have limited the applicability of Emergency AD 2009-07-51 to lever assemblies with less than 50 hours time-in-service (TIS). It issued the superseding Emergency AD to retain all of the requirements of Emergency AD 2009-07-51 but to reduce the applicability to only those helicopters with lever assemblies that have less than 50 hours TIS that may be affected by the unsafe condition.

The FAA reviewed Bell Alert Service Bulletin (ASB) No. 206-09-121, No. 206L-09-155, No. 407-09-85, and No. 427-09-23, all dated March 10, 2009. The ASBs specify that a certain bearing was installed incorrectly on the copilot lever assembly. The ASBs specify, before further flight, inspecting certain serial-numbered Bell helicopters for correct installation of the bearing.

Transport Canada, the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on certain helicopters with less than 50 flight hours or with a lever assembly installed within the last 50 flight hours.

Transport Canada advises that “it is possible that an incorrectly installed bearing could be found in any helicopter with a cyclic control lever assembly recently installed.” Failure of the lever assembly could lead to loss of control of the helicopter. Transport Canada classified the ASBs as mandatory and issued AD No. CF-2009-10, dated March 12, 2009, to ensure the continued airworthiness of these helicopters in Canada.

These helicopter models are manufactured in Canada and are type certificated for operation in the United States under the provisions of 14 CFR 21.29 and the applicable bilateral agreement. Pursuant to the applicable bilateral agreement, Transport Canada has kept the FAA informed of the situation described above. The FAA has examined the findings of Transport Canada, reviewed all available information, and determined that AD action is necessary for products of these type designs that are certificated for operation in the United States.