AD Proposed for Bell 407 Pilot Cyclic Stick Tube

The FAA has proposed to adopt a new airworthiness directive (AD) for certain Bell Textron Canada Limited (Bell) Model 407 helicopters. This proposed AD was prompted by a report of a fractured pilot cyclic stick tube and subsequent findings of other pilot cyclic stick tubes with fatigue cracking. This proposed AD would require repetitively inspecting the pilot cyclic stick tube assembly for a crack and, depending on the results, repairing or replacing the pilot cyclic stick tube assembly. 

Transport Canada has issued AD CF-2024-18, dated May 29, 2024, to correct an unsafe condition on Bell Model 407 helicopters with a pilot cyclic stick tube assembly part number (P/N) 206-001-342-101 or 206-001-342-101FM installed. Bell received a report that a pilot cyclic stick tube assembly fractured at the lower end of the tube near the upper slotted area where it is held in place in the pivot assembly. Examination of the fractured pilot cyclic stick tube and subsequent findings of other cracked pilot cyclic stick tubes revealed fatigue cracking. Further investigation identified the root cause of the pilot cyclic stick tube cracking as the application of excessive force to the cyclic stick during the freedom of movement of the controls and cyclic centering light operation check as part of the interior and prestart check, which resulted in elevated stress at the slotted area and was aggravated by the high stress concentration design feature of the upper slotted area. 

This proposed AD would apply to all Bell 407 helicopters with affected cyclic stick tube assembly P/Ns installed, and would require accomplishing some of the actions specified in Transport Canada AD CF-2024-18 and Bell ASB 407-23-130, Revision A, dated 27 March 2023. In addition, for pilot cyclic stick tube assemblies that have accumulated 3,600 or more hours time-in-service, even if no cracks are identified on an initial inspection, repetitive detailed inspections at intervals not to exceed 300 hours time-in-service will be required. 

You can view the proposed AD here. Comments are due January 2, 2026.