2012-SW-069-AD Airbus Helicopters (Previously Eurocopter France Helicopters) Model SA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters, to require checking certain tail rotor gearbox (TDB) oil level, inspecting the magnetic plug, replacing the TGB guide brush, and measuring for play.