Airworthiness Directives; Airbus Helicopters Deutschland GmbH Helicopters

[Federal Register Volume 90, Number 220 (Tuesday, November 18, 2025)]
[Rules and Regulations]
[Pages 51504-51506]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-20135]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-1106; Project Identifier MCAI-2023-01052-R; 
Amendment 39-23159; AD 2025-20-06]
RIN 2120-AA64


Airworthiness Directives; Airbus Helicopters Deutschland GmbH 
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: 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.

DATES: 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.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov 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.
    Material Incorporated by Reference:
    <bullet> 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: [email protected]; 
website: easa.europa.eu. You may find this material on the EASA website 
at ad.easa.europa.eu.
    <bullet> You may view this material at the FAA, Office of the 
Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-
321, Fort Worth, TX

[[Page 51505]]

76177. For information on the availability of this material at the FAA, 
call (817) 222-5110. It is also available at regulations.gov under 
Docket No. FAA-2025-1106.

FOR FURTHER INFORMATION CONTACT: Aryanna Sanchez, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
phone: (817) 222-4058; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    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 Federal Register 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 regulations.gov under 
Docket No. FAA-2025-1106.

Discussion of Final Airworthiness Directive

Comments

    The FAA received no comments on the NPRM or on the determination of 
the costs.

Additional Changes Made to This AD

    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.

Conclusion

    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.

Material Incorporated by Reference Under 1 CFR Part 51

    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 ADDRESSES section.

Differences Between This AD and the MCAI

    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.

Interim Action

    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.

Costs of Compliance

    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.

Authority for This Rulemaking

    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

[[Page 51506]]

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 that authority because it addresses 
an unsafe condition that is likely to exist or develop on products 
identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2025-20-06 Airbus Helicopters Deutschland GmbH: Amendment 39-23159; 
Docket No. FAA-2025-1106; Project Identifier MCAI-2023-01052-R.

(a) Effective Date

    This airworthiness directive (AD) is effective December 23, 
2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Airbus Helicopters Deutschland GmbH Model 
MBB-BK 117 D-2 and MBB-BK 117 D-3 helicopters, certificated in any 
category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 2100, Air 
Conditioning System.

(e) Unsafe Condition

    This AD was prompted by reports of airspeed and altitude 
indication errors. The FAA is issuing this AD to address airspeed 
and altitude indication errors. The unsafe condition, if not 
addressed, could lead to reduced situational awareness, possibly 
resulting in a significant increase in crew workload.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Requirements

    (1) 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 AD 
2023-0175, dated October 5, 2023 (EASA AD 2023-0175).
    (2) The owner/operator (pilot) holding at least a private pilot 
certificate may revise the existing Rotorcraft Flight Manual for the 
helicopter and must enter compliance with this requirement into the 
helicopter maintenance records in accordance with 14 CFR 43.9(a) and 
14 CFR 91.417(a)(2)(v). The record must be maintained as required by 
14 CFR 91.417, 121.380, or 135.439.

(h) Exceptions to EASA AD 2023-0175

    (1) Where EASA AD 2023-0175 refers to its effective date, this 
AD requires using the effective date of this AD.
    (2) Where EASA AD 2023-0175 requires compliance in terms of 
flight hours, this AD requires using hours time-in-service.
    (3) Where paragraph (1) of EASA AD 2023-0175 states ``by 
incorporating the air conditioning system (ACS) rotorcraft flight 
manual supplement (RFMS) altitude correction procedure, as defined 
in appendix 1 of this AD'', this AD requires replacing that text 
with ``by incorporating the ACS RFMS altitude correction procedure, 
as defined in appendix 1 of this AD, into the Limitations section 
and by adding a visual flight rules (VFR) only restriction to the 
procedure''.
    (4) Where paragraph (1) of EASA AD 2023-0175 specifies to inform 
all flight crews, and operate the helicopter accordingly, this AD 
does not require those actions as those actions are already required 
by existing FAA operating regulations (see 14 CFR 91.505 and 14 CFR 
135.21).
    (5) Where paragraph (2) of EASA AD 2023-0175 states ``which 
includes the same content as the ACS RFMS altitude correction 
procedure'', this AD requires replacing that text with ``which 
includes information identical to the information in the ACS RFMS 
altitude correction procedure, as defined in appendix 1 of this 
AD''.
    (6) This AD does not adopt the ``Remarks'' section of EASA AD 
2023-0175.

(i) No Reporting Requirement

    Although the material referenced in EASA AD 2023-0175 specifies 
to submit certain information to the manufacturer, this AD does not 
include that requirement.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, International Validation Branch, FAA, has the 
authority to approve AMOCs for this AD, if requested using the 
procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, 
send your request to your principal inspector or local Flight 
Standards District Office, as appropriate. If sending information 
directly to the manager of the International Validation Branch, send 
it to the attention of the person identified in paragraph (k) of 
this AD and email to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Additional Information

    For more information about this AD, contact Aryanna Sanchez, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone (817) 222-4058; email: 
[email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference of the material listed in this paragraph 
under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material as applicable to do the actions 
required by this AD, unless the AD specifies otherwise.
    (i) European Union Aviation Safety Agency (EASA) AD 2023-0175, 
dated October 5, 2023.
    (ii) [Reserved]
    (3) For EASA material identified in this AD, contact EASA, 
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 
000; email: [email protected]; website: easa.europa.eu. You may 
find this EASA material on the EASA website at ad.easa.europa.eu.
    (4) 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.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on November 14, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division,Aircraft 
Certification Service.
[FR Doc. 2025-20135 Filed 11-17-25; 8:45 am]
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