Airworthiness Directive · Amendment 39-22057 · Main rotor system
Airbus Helicopters Deutschland GmbH (AHD) Helicopters
This AD applies to all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, MBB-BK117 C-2, and MBB-BK117 D-2 helicopters, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK117 A-1, MBB- BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, MBB-BK117 C-2, and MBB-BK117 D-2 helicopters. This AD was prompted by the FAA's determination that aging of the elastomeric material of certain tension torsion straps (TT-Straps), during the period since manufacturing date up to first flight on a helicopter, may affect its structural characteristics. This AD requires the replacement of certain TT-Straps, implementation of storage life limits for TT-Straps, a prohibition on installing certain TT-Straps, and conditions for installation of certain other TT-Straps, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2021-0122, dated May 6, 2021 (EASA AD 2021-0122).
(1) Where EASA AD 2021-0122 refers to its effective date, this AD requires using the effective date of this AD.
(2) Where EASA AD 2021-0122 specifies the “cure date” of a TT-Strap, the cure date can be determined using the information provided in the service information specified in EASA AD 2021-0122, or by contacting Airbus Helicopters Deutschland GmbH for applicable instructions. If the option of contacting Airbus Helicopters Deutschland GmbH for instructions is chosen, those instructions must be approved by the Manager, General Aviation & Rotorcraft Section, International Validation Branch, FAA; or EASA; or Airbus Helicopters' EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.
(3) This AD does not mandate compliance with the “Remarks” section of EASA AD 2021-0122.
(4) Where the service information referenced in EASA AD 2021-0122 specifies scrapping a part, this AD requires removing that part from service.
(5) Where paragraph (1) of EASA AD 2021-0122 specifies to replace each Lord TT-Strap and Bendix TT-Strap “in accordance with the instructions of the applicable ASB,” for this AD, the replacement must be done using FAA-approved procedures.
(6) Where EASA AD 2021-0122 refers to the airworthiness limitations items of the airworthiness limitations section of the aircraft maintenance manual (AMM) for the definition of service life limit (SLL), this AD requires using the life limits specified in paragraphs (h)(6)(i) through (iii) of this AD, as applicable.
(i) For Bendix TT-Strap P/N 2604067 and P/N 117-14110: Before 10 years or 25,000 flight cycles on the part, whichever occurs first.
(ii) For Lord TT-Strap P/N J17322-1 and P/N 117-14111: Before 12 years or 40,000 flight cycles on the part, whichever occurs first.
(iii) For Lord TT-Strap P/N B622M10T1001: Before 12 years or 30,000 flight cycles on the part, whichever occurs first.
(7) Where table 1 of EASA AD 2021-0122 specifies a compliance time of “During the next helicopter periodical inspection or within 2 months, whichever occurs later after the effective date of this AD, but not exceeding the SLL,” for this AD, the compliance time is “Within 2 months after the effective date of this AD but not exceeding the applicable SLL specified in paragraphs (h)(6)(i) through (iii) of this AD.”
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.
