Airworthiness Directive · Amendment 39-19587 · Main rotor drive system
Airbus Helicopters Deutschland GmbH (Previously Eurocopter Deutschland GmbH) Helicopters
This AD applies to Airbus Helicopters Deutschland GmbH (previously Eurocopter Deutschland GmbH) Model MBB-BK 117 A-1, MBB- BK 117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB- BK 117 C-1 helicopters, certificated any category, with a main rotor (M/R) mast assembly part number 4639 205 011 installed.
We are superseding Airworthiness Directive (AD) 97-26-03 for Eurocopter Deutschland GmbH Model MBB-BK 117 A-1, MBB-BK 117 A-3, MBB- BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117 C-1 helicopters. AD 97-26-03 required visual inspections for cracks in the ribbed area of the main rotor (M/R) mast flange (flange). Since we issued AD 97-26-03, we have determined that a certain reinforced M/R mast is not affected by the unsafe condition. This new AD retains the requirements of AD 97-26-03 and removes a certain M/R mast from the applicability. The actions of this AD are intended to address an unsafe condition on these products.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
