Airworthiness Directive · Amendment 39-12056 · Eurocopter Deutschland GMBH Model MBB-BK 117 Helicopters
Eurocopter Deutschland GMBH Model MBB-BK 117 Helicopters
Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, certificated in any category.
This amendment supersedes an existing airworthiness directive (AD) that applies to Eurocopter Deutschland GMBH (ECD) Model MBB-BK 117 helicopters. That AD currently requires, before further flight, creating a component log card or equivalent record and determining the calendar age and number of flights on each tension-torsion (TT) strap. This amendment establishes a life limit for certain main rotor TT straps. This amendment is prompted by an accident in which a main rotor blade (blade) separated from an ECD Model MBB-BK 117 helicopter due to fatigue failure of a TT strap. The actions specified by this AD are intended to prevent fatigue failure of a TT strap, loss of a blade, and subsequent loss of control of the helicopter.
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.
