Airworthiness Directive · Amendment 39-13424 · Eurocopter Deutschland Model MBB-BK-117 A-1, A-3, A-4, B-1, B-2, and C-1 Helicopters
Eurocopter Deutschland Model MBB-BK-117 A-1, A-3, A-4, B-1, B-2, and C-1 Helicopters
Model MBB-BK-117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters with either: (a) Tail rotor (TR) transmission, part number (P/N) 4639003001 or 4639003007, with serial number (S/N) 900 through 932 plus all S/ Ns overhauled or repaired after July 15, 2001, and bearing, P/N 4639310006, S/N 3246 through 3598; or (b) Intermediate (INT) gearbox, P/N 4639002001 or 4639002005, with S/N 902 through 928 plus all S/Ns overhauled or repaired after July 15, 2001, and bearing, P/N 4639310006 with S/N 3246 through 3598.
This amendment adopts a new airworthiness directive (AD) for Eurocopter Deutschland (Eurocopter) Model MBB-BK-117 A-1, A-3, A-4, B- 1, B-2, and C-1 helicopters with a certain tail rotor (TR) transmission or intermediate (INT) gearbox installed. This action requires inspecting the magnetic plug of the TR transmission and INT gearbox for metal particles before the first flight of each day. Replacing an unairworthy TR transmission, INT gearbox, or bearings with airworthy parts is also required within 30 days after the effective date of this AD. This amendment is prompted by a report of production-related cracks on the cage of bearings installed in certain TR transmissions and INT gearboxes. This condition, if not corrected, could result in cracking and separation of the bearing cage, failure of a bearing, failure of the TR transmission or INT gearbox, and subsequent loss of control of the helicopter.
