FAA Proposes Airworthiness Directive for AHD MBB-BK 117 D-2 Helicopters Over Fuel Leak Risk

The Federal Aviation Administration is proposing a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters, acting under 14 CFR Part 39. The proposed rule was prompted by certification test results involving a certain common cargo hook beam (CCHB) installed on the affected helicopters, which revealed that the CCHB could result in fuel leakage following a survivable accident.

Background and Rationale

According to the proposed rule, the unsafe condition was first identified during certification testing of the CCHB installation on AHD Model MBB-BK117 D-3 and D-3m helicopters. The European Union Aviation Safety Agency (EASA), acting as the Technical Agent for Member States of the European Union, issued EASA AD 2025-0153, dated July 18, 2025, to address this condition on those variants. The FAA's notice states that, due to design similarity, AHD Model MBB-BK117 D-2 helicopters across all variants could also be affected by the same unsafe condition. The FAA further explains that this condition, if not addressed, could lead to fuel leakage and a possible fire after a survivable accident involving a helicopter with a certain CCHB installed. The affected CCHB part number identified in the underlying EASA directive is L851M1301101.

Proposed Requirements

The proposed AD would require modification of the CCHB and fuel system and installation of structural reinforcement, accomplishing the actions specified in EASA AD 2025-0153, which the FAA has incorporated by reference. The proposal also specifies that, as an alternative to the modification, operation of a helicopter with the affected CCHB part number installed would be prohibited. Additionally, the proposed AD would prohibit installing the affected CCHB on any helicopter. The EASA directive also specifies procedures to modify the helicopter by installing an improved cargo hook weighing system concurrently with the CCHB and fuel system modification.

The FAA notes that these products have been approved by the civil aviation authority of another country and are approved for operation in the United States, and that pursuant to the FAA's bilateral agreement with the State of Design Authority, that authority notified the FAA of the unsafe condition. The FAA states it is issuing this NPRM after determining that the unsafe condition is likely to exist or develop on other products of the same type design.

What to Watch

The FAA must receive public comments on this NPRM by November 30, 2026. Comments should reference Docket No. FAA-2026-11812; Project Identifier MCAI-2025-01222-R. The agency states it will consider all comments received by the closing date and may amend the proposal as a result. Submissions containing Confidential Business Information should be directed separately to the designated Aviation Safety Engineer and must be marked "PROPIN" on each relevant page.

Related

• Build hub
• FAA Issues Final Airworthiness Directive for Boeing 757 and 767 Over 5G C-Band Radio Altimeter Interference in Canadian Airspace
• FERC Advances Four Energy Infrastructure Proceedings; FAA Issues Immediate Boeing 737 Airworthiness Fix
• FERC Discloses Exempt Off-the-Record Communication in Docket ER26-2389-000