Last week, the FAA issued an Emergency Airworthiness Directive (AD) to owners and operators of Bell Model 407 helicopters. (AD) 2023-17-51 stems from a report of a disbonded area in a Bell 407’s tail rotor blade “due to missing adhesive between the upper skin and core.” According to Transport Canada, which has issued its own Emergency AD, a Bell 407 operator heard an “abnormal sound” while manually rotating the tail rotor. A “tap inspection” revealed enough disbanded area in the blade to exceed allowable limits.
Subsequently, the manufacturer Bell Textron Canada Limited investigated and determined that a total of 43 tail rotor blades could have missing adhesive between their upper skin and core as a result of issues in the manufacturing process.
According to the FAA, “The initial action required by this emergency AD must be accomplished within 10 hours time-in-service or 14 days, whichever occurs first. This compliance time is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b)(3)(B).”
