FAA Proposes Airworthiness Directive to Prevent Fuel Leakage on Airbus MBB-BK 117 D-2 Helicopters After Survivable Accidents
ANALYSIS · October 15, 2026
Slug: airworthiness-directives-airbus-helicopters-deutschland-gmbh-ahd
Package note: This document is a Notice of Proposed Rulemaking (NPRM) published in the Federal Register on October 15, 2026 (91 FR 65492), Docket No. FAA-2026-11812. It proposes a new airworthiness directive (AD) under 14 CFR Part 39 that would require modification of the common cargo hook beam (CCHB) and fuel system plus structural reinforcement on all affected U.S.-registered helicopters. It does not issue a final rule, impose immediate legal obligations, or affect helicopters outside the defined applicability.
Primary sources
- Federal Register Documents (October 15, 2026): https://www.federalregister.gov/documents/2026/10/15/2026-21123/airworthiness-directives-airbus-helicopters-deutschland-gmbh-ahd-helicopters
The FAA has proposed a new airworthiness directive for all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-2 helicopters. The proposal stems from certification testing that showed a certain common cargo hook beam installation could cause fuel leakage after a survivable accident. If adopted, the AD would require modification of the CCHB and fuel system, installation of structural reinforcement, and would prohibit installation of the affected CCHB on any helicopter.
Core Tension
The document frames the action as addressing an “unsafe condition” identified through testing on similar models that, due to design similarity, also applies to the entire U.S. fleet of 28 MBB-BK 117 D-2 helicopters. It proposes mandatory modifications estimated to cost operators up to $229,920 per helicopter in one configuration, while offering an alternative prohibition on operating with the affected part. Open questions remain on exact compliance times, which are defined in the incorporated EASA AD 2025-0153 rather than stated directly here, and on whether the final rule will adopt any changes based on public comments due by November 30, 2026.
What the NPRM does
| Section / element | Verified text / effect |
|---|---|
| Applicability | Applies to “all Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters, certificated in any category.” |
| Unsafe condition | Prompted by test results showing the installed CCHB “could result in fuel leakage following a survivable accident.” |
| Required actions | Requires actions in EASA AD 2025-0153: modification of the CCHB and fuel system, installation of structural reinforcement; prohibits installing affected CCHB on any helicopter. |
| Alternative | EASA AD 2025-0153 specifies that, as an alternative to the modification, operating a helicopter with affected CCHB part number L851M1301101 installed is prohibited. |
| Exceptions | Uses “effective date of this AD,” converts flight hours to “hours time-in-service,” replaces “discard” with “remove from service,” replaces “check” with “inspect,” and does not adopt the “Remarks” section. |
| Costs | Estimated to affect 28 U.S. helicopters; FAA fleet-wide cost estimates by action: fuel-system modification $700,000; improved fuel pump cartridges $930,972; new-CCHB modification up to $6,437,760; retrofit-CCHB modification up to $369,208. |
| Comment deadline | Comments due by November 30, 2026. |
Claims check
| Claim | Assessment | Receipt |
|---|---|---|
| Proposed AD prompted by certification test results showing possible fuel leakage after survivable accident | Verified | Summary and Background sections cite EASA AD 2025-0153 and testing on similar D-3/D-3m models. |
| AD would require modification of CCHB and fuel system plus structural reinforcement | Verified | “Proposed AD Requirements in This NPRM” and (g) Required Actions paragraphs. |
| AD would prohibit installing certain CCHB on any helicopter | Verified | Summary, Material Incorporated by Reference, and EASA AD 2025-0153 description. |
| Unsafe condition could lead to fuel leakage and possible fire | Verified | “Background” and (e) Unsafe Condition paragraphs use nearly identical language. |
| Estimated to affect 28 U.S. helicopters; the new-CCHB option costs up to $229,920 per helicopter | Verified | “Costs of Compliance” table. |
How coverage splits
Not reviewed for this analysis.
Context / what to watch
- November 30, 2026: Deadline for public comments on the NPRM.
- Future final rule: FAA will consider comments received and may amend the proposal before issuing a binding AD with an effective date.
- Incorporated document: Exact compliance times, procedures, and part numbers are located in EASA AD 2025-0153, available in the docket.
Publish-ready ANALYSIS · Kelvic drafter, checked by KVOp against the primary source · 2026-10-15 · for /analysis/airworthiness-directives-airbus-helicopters-deutschland-gmbh-ahd