Summary
The FAA proposes to supersede airworthiness directive (AD) 77- 04-06, which applies to Messerschmitt-Bolkow-Blohm (MBB) (now Airbus Helicopters Deutschland GmbH (AHD)) Model BO-105A and BO-105 C helicopters; AD 2002-13-06, which applies to certain Eurocopter Deutschland GmbH (ECD) (now Airbus Helicopters Deutschland GmbH (AHD)) Model BO-105A, BO-105C, BO-105 C-2, BO-105 CB-2, BO-105 CB-4, BO-105 CS-2, BO-105 CBS-2, BO-105S, and BO-105LS A-1 helicopters; AD 2016-25- 14, which applies to certain Airbus Helicopters Deutschland GmbH (AHD) Model BO-105LS A-3 helicopters; and AD 2021-10-14, which applies to certain Airbus Helicopters Deutschland GmbH (AHD) Model BO-105A, BO- 105C, BO-105S, and BO-105LS A-3 helicopters. AD 77-04-06 requires reducing the life limit on certain main rotor gearbox (MGB) supports. AD 2002-13-06 requires determining the calendar age, number of flights, and flight hours time-in-service (TIS) on certain tension-torsion (TT) straps; revising the Airworthiness Limitations Schedule (ALS) of the existing maintenance manual; removing and replacing each TT strap that has exceeded its life limit, or if the TT strap's total hours TIS or number of flights and age are not known; and modifying certain parts. AD 2016-25-14 requires establishing a life limit for certain TT straps and removing certain parts that have exceeded the new life limit. AD 2021-10-14 requires replacement of certain TT straps with serviceable parts, and implementation of a new storage life limit for certain TT straps. Since the FAA issued those ADs, new and more restrictive airworthiness limitations have been issued. This proposed AD would require incorporating into existing maintenance records requirements (airworthiness limitations) as specified in a European Union Aviation Safety Agency (EASA) AD, which is proposed for incorporation by reference (IBR). This proposed AD would also prohibit the installation of certain part-numbered TT straps. The FAA is proposing this AD to address the unsafe condition on these products.