Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-1106; Project Identifier MCAI-2023-01052-R; Amendment 39-23159; AD 2025-20-06]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-2 and MBB-BK 117 D-3 helicopters. This AD was prompted by reports of airspeed and altitude indication errors. This AD requires revising the existing rotorcraft flight manual supplement (RFMS) for the helicopter, replacing the air conditioning system (ACS) condenser outlet grids with ACS condenser outlet covers, and prohibiting the installation of ACS condenser outlet grids. The FAA is issuing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This AD is effective December 23, 2025. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of December 23, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-1106; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. <E T="03">Material Incorporated by Reference:</E> • For European Union Aviation Safety Agency (EASA) material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: <E T="03">ADs@easa.europa.eu;</E> website: <E T="03">easa.europa.eu.</E> You may find this material on the EASA website at <E T="03">ad.easa.europa.eu.</E> • You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2025-1106. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Aryanna Sanchez, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-4058; email: <E T="03">aryanna.t.sanchez@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Background</HD> The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 D-2 and MBB-BK 117 D-3 helicopters. The NPRM was published in the <E T="04">Federal Register</E> on June 18, 2025 (90 FR 25911). The NPRM was prompted by AD 2023-0175, dated October 5, 2023, issued by EASA, which is the Technical Agent for the Member States of the European Union (EASA AD 2023-0175) (also referred to as the MCAI). The MCAI states that there have been reports of airspeed and altitude indication errors. Subsequent investigation revealed that the ACS condenser outlets are in close proximity to the static ports, and air from the outlets affects the static ports during flight. The static ports and pitot tubes measure different pressures, which are then used to calculate airspeed, altitude, and vertical speed. Incorrect readings can then occur. This condition, if not corrected, could lead to reduced situational awareness, possibly resulting in a significant increase in crew workload. In the NPRM, the FAA proposed to require revising the existing RFMS for the helicopter, replacing the ACS condenser outlet grids with ACS condenser outlet covers, and prohibiting the installation of ACS condenser outlet grids. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-1106. <HD SOURCE="HD1">Discussion of Final Airworthiness Directive</HD> <HD SOURCE="HD1">Comments</HD> The FAA received no comments on the NPRM or on the determination of the costs. <HD SOURCE="HD1">Additional Changes Made to This AD</HD> In the NPRM, the FAA proposed an exception that would not require a note from the referenced service material after replacing the left-hand or right-hand exhaust cowling assembly. However, the FAA has revised this AD to remove that exception because the note is merely a recommendation and does not mandate any action. Therefore, after replacing the left-hand or right-hand exhaust cowling assembly, operators are still required to perform all actions as specified in the required material. <HD SOURCE="HD1">Conclusion</HD> These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, and any other changes described previously, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed EASA AD 2023-0175, which specifies procedures for amending the applicable RFMS by incorporating new altitude corrections if the helicopter has ACS condenser outlet grids, and not covers, installed. EASA AD 2023-0175 also specifies procedures for replacing the ACS condenser outlet grid part number (P/N) D211M1821302 or P/N D211M1822302 with ACS condenser outlet cover P/N D211M1821402 or P/N D211M1822402 and prohibits installing ACS condenser outlet grids on any helicopter. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">Differences Between This AD and the MCAI</HD> The MCAI applies to Model MBB-BK117 D-2m and MBB-BK117 D-3m helicopters, whereas this AD does not because those models do not have an FAA type certificate. The MCAI requires operators to “inform all flight crews” of the revisions to the RFMS, and thereafter to “operate the helicopter accordingly.” However, this AD does not require those actions as those actions are already required by FAA regulations. FAA regulations require operators furnish to pilots any changes to the rotorcraft flight manual (RFM) (for example, 14 CFR 135.21) and that pilots are familiar with the RFM (for example, 14 CFR 91.505). As with any other flight crew training requirement, training on the updated RFM content is tracked by the operators and recorded in each pilot's training record, which is available for the FAA to review. FAA regulations also require pilots to follow the procedures in the existing RFM including all updates. Section 91.9 requires that any person operating a civil aircraft must comply with the operating limitations specified in the RFM. Therefore, including a requirement in this AD to operate the helicopter according to the revised RFM would be redundant and unnecessary. The MCAI does not have any flight restrictions, whereas this AD requires a revision to the RFMS restricting helicopters to operation under visual flight rules (VFR) until the helicopter is modified with ACS condenser outlet covers. The MCAI specifies amending the applicable RFMS, whereas this AD specifically requires amending the Limitations Section of the applicable RFMS. <HD SOURCE="HD1">Interim Action</HD> The FAA considers that this AD is an interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, the FAA might consider further rulemaking. <HD SOURCE="HD1">Costs of Compliance</HD> The FAA estimates that this AD affects 71 helicopters of U.S. registry. Labor costs are estimated at $85 per hour. Based on these numbers, the FAA estimates the following costs to comply with this AD. Replacing the ACS condenser outlet grids takes 20 work-hours and parts cost $970, for an estimated cost of $2,670 per helicopter and $189,570 for the U.S. fleet. Revising the existing RFM for the helicopter takes 1 work-hour for an estimated cost of $85 per helicopter and $6,035 for the U.S. fleet. <HD SOURCE="HD1">Authority for This Rulemaking</HD> Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 18k characters. 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