Rotorcraft News Update: S-76 vertical stabilizer AD proposed
A proposed airworthiness directive for the Sikorsky S-76 would require inspections of the tail rotor vertical stabilizer aft spar assembly every 50 hours after an assembly has 1,000 hours time-in-service. It would also require track and balance of the tail rotor within 30 days and every 200 hours thereafter. The AD would affect an estimated 216 S-76A/B/Cs on the U.S. registry. It was prompted by 26 reports of fatigue cracks on the aft spar assembly web and outer caps since 1998.