- Effective
- May 15, 2025
- Published
- April 10, 2025 · 90 FR 15304–15306
- Issued
- April 29, 2025
- Models
- AC32, CN-235, CN-235-100, CN-235-200, CN-235-300, AS332C and 36 more
- Registered aircraft
- 1,651 matched by model
- Product
- Appliance · Large airplane · Rotorcraft · Small/large airplane · Small airplane
- ATA chapter
- 34 · Navigation
- Amendment
- 39-23002
- Docket
- FAA-2024-2322
- Project
- MCAI-2024-00065-Q
- Issued as
- Final rule
Unofficial copy from the Federal Register XML, document 2025-06066. Only the govinfo PDF is the legal edition. DRS record last changed November 21, 2025.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| Official PDF | 277 KB | a24d55fa…4f9f4ec | 2025-06066.pdf on govinfo.gov |
| Official PDF | 264 KB | 5740b845…4ba039e | 2025-07756.pdf on govinfo.gov |
| Federal Register XML | 26 KB | 540982bf…7de229b | 2025-06066.xml on federalregister.gov |
| Federal Register XML | 20 KB | 03c22ee8…b613a2b | 2025-07756.xml on federalregister.gov |
| FAA DRS HTML | 42 KB | d8396693…8fbd18a | FAA DRS (API key needed) |
| FAA DRS HTML | 36 KB | 751977cf…1d465b7 | FAA DRS (API key needed) |
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Summary
The FAA is correcting an airworthiness directive (AD) that published in the Federal Register. The AD applies to certain Thommen Aircraft Equipment AG (THOMMEN) AC32 Digital Air Data Computers (ADCs). As published, there were typographical errors in the some of the aircraft models in the applicability table. This document corrects those errors. In all other respects, the original document remains the same.
The airworthiness directive
2025-07-01 Thommen Aircraft Equipment AG: Amendment 39-23002; Docket No. FAA-2024-2322; Project Identifier MCAI-2024-00065-Q.
(a) Effective Date
PDF page 1This airworthiness directive (AD) is effective May 15, 2025.
(b) Affected ADs
PDF page 1None.
(c) Applicability
PDF page 2(1) This AD applies to Thommen Aircraft Equipment AG (THOMMEN) AC32 Digital Air Data Computers (ADCs) having an affected part as defined in paragraph (f)(1) of this AD.
(2) This appliance is installed on, but not limited to, the following aircraft models specified in table 1 to paragraph (c)(2) of this AD, certificated in any category.
| Type certificate holder | Aircraft model |
|---|---|
| Airbus Defense and Space S.A. (type certificate previously held by Construcciones Aeronauticas, S.A.) | CN-235, CN-235-100, CN-235-200, and CN-235-300. |
| Airbus Helicopters | AS332C, AS332C1, AS332L, AS332L1, AS332L2. |
| Airbus Helicopters Deutschland GmbH (AHD) | EC635T2+. |
| Bell Textron Inc | 212, 412, and 412EP. |
| Bombardier Inc | CL-600-1A11 (600). |
| Columbia Helicopters Inc | 107-II, 234. |
| General Atomics Aerotek Systems GmbH (type certificate formerly held by DORNIER LUFTFAHRT Inc.) | 228-100, 228-101, 228-200, 228-201, 228-202, and 228-212. |
| Gulfstream Aerospace LP | Westwind Astra 1124 (serial numbers 004-0410). |
| International Air Response | C-130A. |
| Kawasaki Heavy Industries, Limited | KV107-II. |
| Leonardo S.p.a | A109, A109A, A109A II, A109C, A109K2, A109S, AW109SP, AW139, and AW189. |
| Textron Aviation Inc | 200, 300, 500, 501, 550, and 551. |
| Viking Air Limited | CL-215-6B11 (CL-215T Variant). |
(3) This appliance is approved for installation and could be installed on various aircraft modified by Supplemental Type Certificate (STC) No. SR09595RC or ST01523WI.
(d) Subject
PDF page 2Joint Aircraft System Component (JASC) Code 3417, Air Data Computer.
(e) Unsafe Condition
PDF page 2This AD was prompted by occurrences of AC32 Digital ADCs that stopped functioning due to the power module failing at temperatures below −20 degrees Celsius. The unsafe condition, if not addressed, could result in insufficient navigational data provided to the flight crew, resulting in reduced control of the aircraft.
(f) Definitions
PDF page 2For the purpose of this AD the definitions in paragraphs (f)(1) through (4) of this AD apply:
(1) Affected part: THOMMEN AC32 Digital ADCs, part numbers (P/N) AC32.10.21.10.XX, AC32.10.21.11.XX, AC32.11.21.10.XX, and AC32.11.21.11.XX (where XX represents any alpha/numerical sequence), and having a serial number (S/N) listed in Appendix A of THOMMEN AIRCRAFT EQUIPMENT Service Bulletin SB AC32/07, Revision 1.0, dated August 31, 2023 (THOMMEN SB AC32/07 Revision 1.0).
(2) Serviceable part: Any AC32.(X) Digital ADC that is not an affected part; or an affected part where the power module has been replaced by THOMMEN, in accordance with the instructions of THOMMEN SB AC32/07 Revision 1.0.
(3) Group 1 aircraft: Have an affected part installed.
(4) Group 2 aircraft: Do not have an affected part installed but are eligible for AC32.(X) Digital ADC installation.
(g) Compliance
PDF page 2Comply with this AD within the compliance times specified, unless already done.
(h) Required Actions
PDF page 2For Group 1 aircraft: Within 12 months after the effective date of this AD, remove each affected part from service and replace it with a serviceable part in accordance with paragraph 3.A. of the Accomplishment Instructions in THOMMEN SB AC32/07 Revision 1.0, except where this material specifies to send the removed affected part to the manufacturer, this AD does not require that action.
(i) Parts Installation Prohibition
PDF page 2For Group 1 and 2 aircraft: As of the effective date of this AD, do not install an affected part on any aircraft.
(j) Special Flight Permits
PDF page 2A one-time special flight permit may be issued in accordance with 14 CFR 21.197 and 21.199 in order to fly to a maintenance base to perform the required action in this AD, provided a flight profile above −15 degrees Celsius (5 degrees Fahrenheit) is maintained.
(k) Alternative Methods of Compliance (AMOCs)
PDF page 2(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 International Validation Branch, send it to the attention of the person identified in paragraph (l) of this AD and email to: AMOC@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.
(l) Additional Information
PDF page 2For more information about this AD, contact William Reisenauer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (516) 228-7301; email: 9-AVS-AIR-BACO-COS@faa.gov.
(m) Material Incorporated by Reference
PDF page 2(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.
(3) The following material was approved for IBR on May 15, 2015 (90 FR 15304, April 10, 2025).
(i) Thommen Aircraft Equipment Service Bulletin SB AC32/07, Revision 1.0, dated August 31, 2023.
(ii) [Reserved]
(4) For Thommen Aircraft Equipment material in this AD, contact THOMMEN, Hofackerstrasse 48, 4132 Muttenz, Switzerland; phone: +41 (0) 61 965 22 22; email: sales@thommen.aero; website: thommen.aero.
(5) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call (817) 222-5110.
(6) 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 fr.inspection@nara.gov.
Rule preamble
The FAA’s background, reasoning and cost estimate, published with the AD.
DatesPage 1
This correction is effective May 15, 2025. The effective date of AD 2025-07-01 remains May 15, 2025.
The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 15, 2025 (90 FR 15304, April 10, 2025).
AddressesPage 1
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2024-2322, 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, 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:
• For THOMMEN AIRCRAFT EQUIPMENT material identified in this AD, contact THOMMEN, Hofackerstrasse 48, 4132 Muttenz, Switzerland; phone: +41 (0) 61 965 22 22; email: sales@thommen.aero; website: thommen.aero.
• You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. 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-2024-2322.
For further information contactPage 1
William Reisenauer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (516) 228-7301; email: 9-AVS-AIR-BACO-COS@faa.gov.
Supplementary informationPage 1
AD 2025-07-01, 39-23002 (90 FR 15304, April 10, 2025) (AD 2025-07-01) applies to certain part-numbered and serial-numbered THOMMEN AC32 ADCs and requires removing those ADCs from service. The ADCs are installed on, but not limited to, the aircraft models specified in table 1 to paragraph (c)(2) of the AD.
Need for the CorrectionPage 1
As published, three aircraft models contained typographical errors. Table 1 to paragraph (c)(2) of the AD referred to Airbus Helicopters Model “AS3323L2” when the correct model is “AS332L2.” In addition, Table 1 to paragraph (c)(2) of the AD referred to Leonardo S.p.a. Model “A10A” and “1099SP” when the correct models are “A109A” and “AW109SP.” These aircraft model errors do not affect compliance with the AD because table 1 to paragraph (c)(2) of the AD provides some, but not all, aircraft models on which an applicable ADC may be installed.
Material Incorporated by Reference Under 1 CFR Part 51Page 1
The FAA reviewed THOMMEN AIRCRAFT EQUIPMENT Service Bulletin SB AC32/07, Revision 1.0, dated August 31, 2023 (THOMMEN SB AC32/07, Revision 1.0). This material specifies procedures for determining if an aircraft is equipped with an affected AC32 Digital ADC listed in Appendix A, determining if the actions specified in THOMMEN SB AC32/07, Revision 1.0, were already accomplished, and replacing any affected THOMMEN AC32 Digital ADC.
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.
Correction of PublicationPage 1
This document corrects three errors and correctly adds the AD as an amendment to 14 CFR 39.13. Although no other part of the preamble or regulatory information has been corrected, the FAA is publishing the entire rule in the Federal Register.
The effective date of this AD remains May 15, 2025.
Since this action only corrects three typographical errors and does not affect compliance with the AD, it has no adverse economic impact and imposes no additional burden on any person. Therefore, the FAA has determined that notice and public procedures are unnecessary.
Adoption of the AmendmentPage 1
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
Adoption of the amendmentPage 1
1. The authority citation for part 39 continues to read as follows:
2. The FAA amends § 39.13 by adding the following airworthiness directive:
Affected TCDS · 17
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 1,651
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1950 | 1 |
|---|---|
| 1962 | 5 |
| 1963 | 1 |
| 1964 | 3 |
| 1965 | 1 |
| 1971 | 2 |
| 1972 | 10 |
| 1973 | 13 |
| 1974 | 16 |
| 1975 | 25 |
| 1976 | 23 |
| 1977 | 55 |
| 1978 | 64 |
| 1979 | 116 |
| 1980 | 117 |
| 1981 | 117 |
| 1982 | 56 |
| 1983 | 23 |
| 1984 | 32 |
| 1985 | 27 |
| 1986 | 14 |
| 1987 | 25 |
| 1988 | 57 |
| 1989 | 30 |
| 1990 | 31 |
| 1991 | 30 |
| 1992 | 20 |
| 1993 | 12 |
| 1994 | 3 |
| 1995 | 6 |
| 1996 | 2 |
| 1997 | 17 |
| 1998 | 29 |
| 1999 | 28 |
| 2000 | 33 |
| 2001 | 34 |
| 2002 | 27 |
| 2003 | 19 |
| 2004 | 14 |
| 2005 | 16 |
| 2006 | 16 |
| 2007 | 16 |
| 2008 | 9 |
| 2009 | 11 |
| 2010 | 12 |
| 2011 | 10 |
| 2012 | 17 |
| 2013 | 16 |
| 2014 | 7 |
| 2015 | 7 |
| 2016 | 9 |
| 2017 | 4 |
| 2018 | 4 |
| 2019 | 17 |
| 2020 | 9 |
| 2021 | 1 |
| 2022 | 8 |
| 2023 | 8 |
| 2024 | 13 |
| 2025 | 19 |
| 2026 | 9 |
275 with no year recorded