Airworthiness Directive · Amendment 39-12561 · Sikorsky Model S-70A and S-70C Helicopters
Sikorsky Model S-70A and S-70C Helicopters
Superseded. A later AD replaced this one: AD 2002-11-10. Comply with the one in force.
Model S-70A helicopters, serial numbers 700029, 701129, 701322, 701325, 701327, 701329, 701331, 701333, 701592, 701593,701594, 701595, 701613, 701614, 701825, 701835, 702127, and 702129, and Model S-70C helicopters, serial numbers 70583, 70785, 70788, 70792, 70793, 70794, 70797, 70798, 70799, 70800, 70811, 70812, 70813, 70830, 70831, 70836, 70837, 70848, 70855, 70856, 70867, 70868, 70879, 70884, 70892, 70910, 70918, 70927, 70928, 70929, 70949, 70950, 70951, 70954, 70957, 70958, 70959, 70965, 70966, and 701029, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for Sikorsky Model S-70A and S-70C helicopters. This action requires certain inspections of each main landing gear drag beam (beam) for a crack and removing any cracked beam before further flight. This action also requires reducing the torque of the jackpad mounting bolt retention nut (nut) of each beam. This amendment is prompted by failure of a beam due to stress corrosion resulting from sustained tensile stress due partly to excessive torque of the nut. The actions specified in this AD are intended to prevent excessive torque of the nut, failure of a beam, and subsequent loss of control of the helicopter during takeoff or landing.
