AD NUMBER: 2019-05-05

PRODUCT: 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.

ACTION: Final Rule.

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 97-26-03 for the aircraft listed above. AD 97-26-03 required visual inspections for cracks in the ribbed area of the main rotor (M/R) mast flange (flange).

Since issuing AD 97-26- 03, the FAA has 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.

DATES: This AD is effective April 17, 2019.

COST: The FAA estimates that this AD affects 62 helicopters of U.S. Registry. Operators may incur the following costs in order to comply with this AD:

Labor costs are estimated at $85 per work-hour.

Visually inspecting the flange for a crack requires 0.25 work-hour for an estimated cost of about $21 per helicopter and $1,302 for the U.S. fleet per inspection cycle. Replacing the M/R mast requires 10 work-hours and parts cost $50,000 for an estimated cost of $50,850 per helicopter.

FMI: AD