Airworthiness Directive · Amendment 39-21632 · Main rotor blades
Airbus Helicopters Deutschland GmbH Helicopters
This AD applies to all Airbus Helicopters 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 in any category.
The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters 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. This AD was prompted by a report of sudden severe vibrations and a cracked open blade trailing edge caused by a loosened lead inner weight. This AD requires inspections to determine if any bolted main rotor blades are installed, and replacement of the affected main rotor blades. The FAA is issuing this AD to address the unsafe condition on these products.
Within 30 days after the effective date of this AD, review the log card (or equivalent record) and visually inspect each main rotor blade to determine if any bolted main rotor blades (i.e., main rotor blade with bolted lead inner weight) are installed in accordance with paragraphs 2.A.1., 2.B.1., 2.B.2., and 2.B.3. of the Accomplishment Instructions of Eurocopter Alert Service Bulletin No. ASB-MBB-BK117-10-125, dated February 14, 2005. If during the review, the total hours time-in-service (TIS) cannot be positively determined, this AD requires treating that part as having accumulated more than 3,000 total hours TIS. If any bolted main rotor blade (i.e., main rotor blade with bolted lead inner weight) is installed, replace the main rotor blade in accordance with paragraph 2.B.4. of the Accomplishment Instructions of Eurocopter Alert Service Bulletin ASB-MBB-BK117-10-125, dated February 14, 2005, as follows:
(1) For a bolted main rotor blade that has accumulated less than 2,300 total hours TIS on the blade since bolting of the lead inner weight as of the effective date of this AD: Before accumulating 2,500 total hours TIS on the blade since bolting of the lead inner weights.
(2) For a bolted main rotor blade that has accumulated 2,300 total hours TIS up to 3,000 total hours TIS inclusive, on the blade since bolting of the lead inner weight as of the effective date of this AD: Within 200 hours TIS after the effective date of this AD.
(3) For a bolted main rotor blade that has accumulated more than 3,000 total hours TIS on the blade since bolting of the lead inner weight as of the effective date of this AD: Within 50 hours TIS after the effective date of this AD.
Where Eurocopter Alert Service Bulletin ASB-MBB-BK117-10-125, dated February 14, 2005, specifies to send a form to the manufacturer to determine TIS since bolting, this AD does not include that requirement.
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.
