Summary
This document proposes superseding Airworthiness Directives (AD) 2000-05-17 and AD 2001-04-12, which apply to Eurocopter France (now Airbus Helicopters) Model EC120B helicopters. AD 2000-05-17 and AD 2001-04-12 require repetitive visual checks of the engine-to-main gearbox (MGB) coupling tube assembly (coupling tube) for a crack and replacing any cracked tube with an airworthy tube. This proposed AD would require removing certain engine mount parts from service, measuring the height of the engine mounting base for certain helicopters, replacing the engine mount if a certain height is exceeded, inspecting the flared coupling on certain helicopters for a crack, and replacing the coupling if it is cracked. Since we issued AD 2000-05-17 and AD 2001-04-12, there have been reports of additional cracks in coupling tubes. The proposed actions are intended to prevent coupling tube failure, loss of engine drive, and a subsequent forced landing of the helicopter.