AD #2021-05-52 Prompted By A Report Of A Cracked Pilot Collective Stick

An Emergency Airworthiness Directive (AD) 2021-05-52 is being sent to owners and operators of certain Bell Textron Canada Limited (Bell) Model 505 helicopters.

This emergency AD was prompted by a report of a cracked pilot collective stick and grip assembly (pilot collective stick) that was discovered during a pre-flight check of the flight controls. This emergency AD requires, before further flight, visually inspecting the pilot collective stick for a crack. If no crack is found during the visual inspection, performing a fluorescent penetrant inspection (FPI) for a crack is required. Removing from service any cracked pilot collective stick is required before further flight. This emergency AD also requires reporting certain information to Bell and prohibits installing any pilot collective stick on any helicopter unless the inspection requirements have been accomplished. The unsafe condition, if not addressed, could result in failure of the pilot collective stick and subsequent loss of control of the helicopter.

Transport Canada, which is the aviation authority for Canada, has issued Transport Canada Emergency AD CF-2021-05, dated February 21, 2021, to correct an unsafe condition for Bell Model 505 helicopters, serial numbers 65011 and subsequent. Transport Canada advises of a report that a pilot collective stick cracked above the cabin floor at the junction with the collective jackshaft. This finding occurred prior to engine start during the pilot pre-flight check of flight controls for travel. The exact cause of the crack is still under investigation; due to the potential for similar failure on other Bell Model 505 helicopters, Transport Canada advises that a one-time inspection per Bell’s service information is required to detect cracks that may lead to failure of the pilot collective stick and subsequent loss of control of the helicopter.

Accordingly, the Transport Canada AD requires a one-time visual inspection and as applicable, an FPI of the pilot collective stick to detect cracking. If the pilot collective stick is found to be unserviceable, the Transport Canada AD requires replacing the collective stick with a serviceable part prior to further flight. Transport Canada advises that a serviceable collective stick is a new collective stick or a collective stick with no crack found during the visual inspection or FPI required by its AD. Transport Canada considers its AD an interim action and states that further AD action may follow.

FAA’s Determination: This helicopter model has been approved by the aviation authority of Canada and is approved for operation in the United States. Pursuant to the FAA’s bilateral agreement with Canada, Transport Canada, its technical representative, has notified the FAA of the unsafe condition described in its AD. The FAA is issuing this emergency AD after evaluating all known relevant information and determining that the unsafe condition described previously is likely to exist or develop on other helicopters of the same type design.

Related Service Information: The FAA reviewed Bell Alert Service Bulletin 505-21-20, dated February 20, 2021 (ASB 505-21-20). This service information provides instructions for a one-time inspection for cracks of the pilot collective stick and grip assembly part number M207-20M478-041/-043/-047 on Bell Model 505 helicopters, serial numbers 65011 and subsequent.

Emergency AD Requirements: This emergency AD requires, before further flight, removing the pilot collective stick from the jackshaft assembly and cleaning it as specified in ASB 505-21-20. This emergency AD also requires visually inspecting the complete circumference of the areas specified in ASB 505-21-20 for a crack. If the visual inspection does not reveal a crack, this emergency AD requires performing an FPI for a crack as specified in American Society for Testing and Materials (ASTM) E1417 or equivalent; this inspection is required in the areas specified in ASB 505-21-20. Removing from service any cracked pilot collective stick is required before further flight.

This emergency AD also requires, within 10 days after the discovery of any crack, reporting certain information to Bell. Finally, this emergency AD prohibits installing any pilot collective stick unless it has been inspected in accordance with the inspection requirements of this emergency AD.

FMI: www.regulations.gov