Airworthiness Directive · Amendment 39-23277 · Main rotor head
Airbus Helicopters Deutschland GmbH (AHD) Helicopters
This AD applies to all Airbus Helicopters Deutschland GmbH (AHD) 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 (AHD) 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 a main rotor head (MRH) having the same part number (P/N) and serial number (S/N) as another MRH due to incorrect modification instructions where the modified part S/N was not re-identified and the MRH can be operated with the wrong associated log card if accidently interchanged. This AD requires performing a one-time consistency check of the P/N and S/N of the MRH, performing corrective actions if applicable, determining if the MRH has been modified, and re-identifying the modified MRH. This AD also allows replacing the MRH as an optional action and prohibits the installation of an affected MRH on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2025-0028, dated February 7, 2025 (EASA AD 2025-0028).
(1) Where EASA AD 2025-0028 refers to its effective date, this AD requires using the effective date of this AD.
(2) Where EASA AD 2025-0028 requires compliance in terms of flight hours, this AD requires using hours time-in-service.
(3) Where paragraphs (2) and (4) of EASA AD 2025-0028 specify discrepancy, for the purposes of this AD, a discrepancy can be defined as the serial number on the MRH [Main Rotor Head] not matching the serial number on the helicopters existing log card or equivalent record.
(4) Where the material referenced in EASA AD 2025-0028 specifies “check”, this AD requires replacing that text with “inspect”.
(5) Where EASA AD 2025-0028 and the material referenced in EASA AD 2025-0028 specifies “MRH log card”, this AD requires replacing that text with “existing helicopter log card or equivalent record”.
(6) Where EASA AD 2025-0028 or the referenced material specifies to contact AH [Airbus Helicopters] to obtain approved instructions, or specifies a part is eligible for installation in accordance with AH instructions, this AD requires those actions done in accordance with a method approved by the Manager, 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.
(7) This AD does not adopt the “Remarks” section of EASA AD 2025-0028.
Although the material referenced in EASA AD 2025-0028 specifies to submit certain information to the manufacturer, this AD does not require that action.
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.
