FAA releases AD on helicopter loss of tail rotor authority

Loss of tail rotor authority in Sikorsky helicopters is the subject of a new airworthiness directive (AD 2026-11-05) from the FAA. Pilots and operators should take notice as it becomes effective on July 9, 2026.The directive states that fatigue fractures in the yaw pedal damper housing and attachment bolt have resulted in a loss of auxiliary system fluid, which could lead to loss of control over the tail rotor.What prompted the ADThe AD follows an accident involving a Sikorsky helicopter that lost tail rotor authority, which was caused by auxiliary system fluid loss through the fractures. During the investigation, a non-conforming yaw pedal damper housing lug radius was identified. Additionally, improper maintenance and improper operation were contributing factors to the unsafe condition. Affected helicopter modelsThe AD covers 76 U.S.-registered helicopters across seven operators, all variants of the Sikorsky S-61 family:Carson Helicopters S-61L and SH-3HCroman Corporation SH-3HGlacier Helicopter CH-3EReynolds Aviation USAF CH-3C, CH-3E, HH-3C, and HH-3ESikorsky Aircraft Corporation S-61A, S-61D, S-61E, and S-61VSikorsky Aircraft S-61L, S-61N, S-61NM, and S-61RSiller Helicopters CH-3E and SH-3ARequired inspections and corrective actionsThe FAA will require that a preflight inspection of the lockwire is needed to ensure it does not rotate under finger pressure. It will also require a visual inspection to be done on the auxiliary servo assembly located in the controls compartment. Operators should look for hydraulic fluid leakage, cracks, missing or loose lockwire and bolts that are loose, missing, cracked, fractured or stretched. Refer to Sikorsky Aircraft Corporation S-61 Helicopter Alert Service Bulletin ASB 61B65-25 for the full corrective action procedures.Operators will have to determine the remaining life of their yaw pedal damper check valve housing within 10 hours of time-in-service once this AD is effective. Its new service life limit is 30,000 hours in service. Within 150 hours TIS or 4 months, whichever occurs first, they must perform a Fluorescent Penetrant Inspection (FPI) on the housing. Once the FPI is complete, operators must then perform the repetitive visual inspection every 15 hours TIS going forward. The helicopters' existing rotorcraft flight manual and airworthiness limitations section of the maintenance manual will need to be updated to meet the requirements of the AD.Compliance costs and impact on owners, operators, and buyersOwners and operators of any of these helicopters will have to pay for these services and replacement parts, with visual inspections expected to cost U.S. operators $6,460 per inspection cycle in aggregate. Additional one-time compliance costs include the FPI, life determination, RFM revision, and maintenance manual update. This extra cost will need to be budgeted for and aircraft part companies should keep yaw pedal damper check valve housing parts in stock as the AD comes into effect.Buyers should consider this issue when purchasing a new helicopter and ensure that their pre-buy inspection includes these parts.