Federal Register / Vol. 89, No. 189 / Monday, September 30, 2024 / Proposed Rules 79477 

check analysis—Aluminum PPM allowable; 

of Austro MSB–E4–039/3, before further 

flight, replace the pistons, piston rings, conrods assembly, and crankcase, or replace the 

engine core in accordance with paragraph 2., 

Technical Details, Engine core replacement; 

or Pistons, piston rings, crankcase and conrod assy replacement; as applicable, of 

Austro MSB–E4–039/3. 

(5) For Group 3 and Group 4 engines, 

within the applicable compliance times 

specified in Table 3 to paragraph (g)(5) of this 

AD, replace the pistons, piston rings, and 

con-rods assembly, or replace the engine core 

in accordance with paragraph 2., Technical 

Details, Engine core replacement; or Pistons, 

piston rings and con-rod assy replacement, as 

applicable, of Austro MSB–E4–039/3. 

TABLE 3 TO PARAGRAPH (g)(5)—REPLACEMENT FOR GROUP 3 AND 4 ENGINES

Engine group Compliance time 

Group 3 engines that do not have an ESN identified in Table 2 to paragraph (g)(1) of this AD.Before exceeding 900 FHs since new, or within 15 FHs after December 11, 2023 (the effective date of AD 2023–20–03), whichever occurs later. 

Group 3 engines that have an ESN identified in Table 2 to paragraph 

(g)(1) of this AD.

Before exceeding 900 FHs since new, or within 15 FHs after the effective date of this AD, whichever occurs later 

Group 4 engines that do not have an ESN identified in Table 2 to paragraph (g)(1) of this AD.Before exceeding 1,000 FHs since new, or within 25 FHs after December 11, 2023 (the effective date of AD 2023–20–03), whichever occurs later. 

Group 4 engines that have an ESN identified in Table 2 to paragraph 

(g)(1) of this AD.

Before exceeding 1,000 FHs since new, or within 25 FHs after the effective date of this AD, whichever occurs later. 

Note 1 to paragraph (g)(5): FHs since new 

indicated in Table 3 to paragraph (g)(5) of 

this AD are FHs accumulated by the engine 

since first installation on an airplane or since 

last overhaul as of December 11, 2023 (the 

effective date of AD 2023–20–03) for Group 

3 and 4 engines that do not have an ESN 

identified in Table 2 to paragraph (g)(1) of 

this AD, or as of the effective date of this AD 

for Group 3 and 4 engines that have an ESN 

identified in Table 2 to paragraph (g)(1) of 

this AD. 

(h) Terminating Action 

(1) Replacement of the pistons, piston 

rings, con-rods assembly, and crankcase, or 

replacement of the engine core, as specified 

in paragraph (g)(4) of this AD, constitutes 

terminating action for the repetitive oil 

analysis required by paragraph (g)(2) of this 

AD. 

(2) Replacement of the pistons, piston 

rings, and con-rods assembly, or replacement 

of the engine core, as specified in paragraph 

(g)(5) of this AD, constitutes terminating 

action for the repetitive oil analysis required 

by paragraph (g)(2) of this AD. 

(i) Definitions 

For the purpose of this AD: 

(1) Group 1 engines are engines having an 

ESN listed in Table 1 of No. MSB–E4–039/ 

3. 

(2) Group 2 engines are engines having an 

ESN listed in Table 2 of No. MSB–E4–039/ 

3. 

(3) Group 3 engines are engines having an 

ESN listed in Table 3 of No. MSB–E4–039/ 

3. 

(4) Group 4 engines are engines having an 

ESN listed in Table 4 of No. MSB–E4–039/ 

3. 

(j) Credit for Previous Actions 

(1) You may take credit for the actions 

required by paragraph (g)(1), (4), or (5) of this 

AD, if you performed those actions before 

December 11, 2023 (the effective date of AD 

2023–20–03) using Austro Engine GmbH 

Mandatory Service Bulletin No. MSB–E4– 

039/0, dated October 24, 2022. 

(2) You may take credit for the actions 

required by paragraph (g)(1), (4), or (5) of this 

AD if you performed those actions before the 

effective date of this AD using Austro Engine 

GmbH Mandatory Service Bulletin No. MSB– 

E4–039/2, Revision 2, dated July 26, 2023. 

(k) No Return of Parts/Reporting 

Requirement 

Although the service information specifies 

returning certain parts and submitting certain 

information to the manufacturer, this AD 

does not include those requirements. 

(l) 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 (m)(1) of this AD and 

email to AMOC@faa.gov. 

(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. 

(m) Additional Information 

(1) For more information about this AD, 

contact Morton Lee, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, Suite 

410, Westbury, NY 11590; phone: (860) 386– 

1791; email: morton.y.lee@faa.gov. 

(2) Material identified in this AD that is not 

incorporated by reference is available at the 

address specified in paragraph (n)(3) of this 

AD. 

(n) Material Incorporated by Reference 

(1) The Director of the Federal Register 

approved the incorporation by reference 

(IBR) 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) Austro Engine GmbH Mandatory Service 

Bulletin No. MSB–E4–039/3, Revision 3, 

dated November 22, 2023. 

(ii) [Reserved] 

(3) For Austro Engine GmbH material 

identified in this AD, contact Austro Engine 

GmbH, Rudolf-Diesel-Strasse 11, A–2700 

Weiner Neustadt, Austria; phone: +43 2622 

23000; website: austroengine.at. 

(4) You may view this material at FAA, 

Airworthiness Products Section, Operational 

Safety Branch, 1200 District Avenue, 

Burlington, MA 01803. 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 fr.inspection@nara.gov. 

Issued on September 23, 2024. 

Steven W. Thompson, 

Acting Deputy Director, Compliance & 

Airworthiness Division, Aircraft Certification 

Service. 

[FR Doc. 2024–22064 Filed 9–27–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–2320; Project 

Identifier MCAI–2024–00268–T] 

RIN 2120–AA64 

Airworthiness Directives; Airbus SAS 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 


ddrumheller on DSK120RN23PROD with PROPOSALS1
79478 Federal Register / Vol. 89, No. 189 / Monday, September 30, 2024 / Proposed Rules 

certain Airbus SAS Model A350–941 

and –1041 airplanes. This proposed AD 

was prompted by an updated stress 

analysis on the forward (FWD) cargo 

door and its attachment piano hinges 

that revealed a risk of cracking and 

crack propagation on piano hinges 2 and 

3, originating from opening-closing 

fatigue cycles of the FWD cargo door. 

This proposed AD would require an 

inspection of the affected parts, and 

applicable corrective actions, as 

specified in a European Union Aviation 

Safety Agency (EASA) AD, which is 

proposed for incorporation by reference 

(IBR). The FAA is proposing this AD to 

address the unsafe condition on these 

products. 

DATES: The FAA must receive comments 

on this proposed AD by November 14, 

2024. 

ADDRESSES: You may send comments, 

using the procedures found in 14 CFR 

11.43 and 11.45, by any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

regulations.gov. Follow the instructions 

for submitting comments. 

• Fax: 202–493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue SE, 

Washington, DC 20590. 

• Hand Delivery: Deliver to Mail 

address above between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–2320; 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 NPRM, the mandatory 

continuing airworthiness information 

(MCAI), any comments received, and 

other information. The street address for 

Docket Operations is listed above. 

Material Incorporated by Reference: 

• For EASA material identified in this 

proposed AD, contact EASA, KonradAdenauer-Ufer 3, 50668 Cologne, 

Germany; telephone +49 221 8999 000; 

email ADs@easa.europa.eu; website 

easa.europa.eu. You may find this 

material on the EASA website at 

ad.easa.europa.eu. It is also available at 

regulations.gov under Docket No. FAA– 

2024–2320. 

• You may view this material at the 

FAA, Airworthiness Products Section, 

Operational Safety Branch, 2200 South 

216th St., Des Moines, WA. For 

information on the availability of this 

material at the FAA, call 206–231–3195. 

FOR FURTHER INFORMATION CONTACT: Dat 

Le, Aviation Safety Engineer, FAA, 1600 

Stewart Avenue, Suite 410, Westbury, 

NY 11590; telephone 516–228–7300; 

email dat.v.le@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

The FAA invites you to send any 

written relevant data, views, or 

arguments about this proposal. Send 

your comments to an address listed 

under the ADDRESSES section. Include 

‘‘Docket No. FAA–2024–2320; Project 

Identifier MCAI–2024–00268–T’’ at the 

beginning of your comments. The most 

helpful comments reference a specific 

portion of the proposal, explain the 

reason for any recommended change, 

and include supporting data. The FAA 

will consider all comments received by 

the closing date and may amend this 

proposal because of those comments. 

Except for Confidential Business 

Information (CBI) as described in the 

following paragraph, and other 

information as described in 14 CFR 

11.35, the FAA will post all comments 

received, without change, to 

regulations.gov, including any personal 

information you provide. The agency 

will also post a report summarizing each 

substantive verbal contact received 

about this NPRM. 

Confidential Business Information 

CBI is commercial or financial 

information that is both customarily and 

actually treated as private by its owner. 

Under the Freedom of Information Act 

(FOIA) (5 U.S.C. 552), CBI is exempt 

from public disclosure. If your 

comments responsive to this NPRM 

contain commercial or financial 

information that is customarily treated 

as private, that you actually treat as 

private, and that is relevant or 

responsive to this NPRM, it is important 

that you clearly designate the submitted 

comments as CBI. Please mark each 

page of your submission containing CBI 

as ‘‘PROPIN.’’ The FAA will treat such 

marked submissions as confidential 

under the FOIA, and they will not be 

placed in the public docket of this 

NPRM. Submissions containing CBI 

should be sent to Dat Le, Aviation 

Safety Engineer, FAA, 1600 Stewart 

Avenue, Suite 410, Westbury, NY 

11590; telephone 516–228–7300; email 

dat.v.le@faa.gov. Any commentary that 

the FAA receives which is not 

specifically designated as CBI will be 

placed in the public docket for this 

rulemaking. 

Background 

EASA, which is the Technical Agent 

for the Member States of the European 

Union, has issued EASA AD 2024–0129, 

dated July 5, 2024 (also referred to as 

the MCAI), to correct an unsafe 

condition for certain Airbus SAS Model 

A350–941 and –1041 airplanes. The 

MCAI states an update of the stress 

analysis resulted in a new definition of 

interface load distribution between the 

FWD cargo door and the associated 

fuselage piano hinges. Further 

investigation revealed a risk of cracking 

and crack propagation on the affected 

parts, originating from opening-closing 

fatigue cycles of the FWD cargo door. 

Under this condition, door operation 

could cause damage to the FWD cargo 

door surrounding structure. 

The FAA is proposing this AD to 

address damage to the FWD cargo door 

surrounding structure, which could 

reduce the structural integrity of the 

airplane. 

You may examine the MCAI in the 

AD docket at regulations.gov under 

Docket No. FAA–2024–2320. 

Material Incorporated by Reference 

Under 1 CFR Part 51 

EASA AD 2024–0129 specifies 

procedures for performing a detailed 

inspection for cracks and damage 

(including dents, discoloration, 

punctures, nicks, and scratches) of the 

FWD cargo door piano hinges 2 and 3, 

and obtaining and following 

instructions for repair of cracks and 

damage. EASA AD 2024–0129 also 

specifies procedures for checking the 

condition and integrity of the temporary 

protection system (TPS) layer, if 

installed, removing any damaged TPS 

layer, and applying a new layer if the 

TPS layer was damaged, removed, or 

cleaned. 

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. 

FAA’s Determination 

This product has been approved by 

the aviation authority of another 

country and is approved for operation in 

the United States. Pursuant to the FAA’s 

bilateral agreement with this State of 

Design Authority, it has notified the 

FAA of the unsafe condition described 

in the MCAI referenced above. The FAA 

is issuing this NPRM after determining 

that the unsafe condition described 

previously is likely to exist or develop 

in other products of the same type 

design. 

Proposed AD Requirements in This 

NPRM 

This proposed AD would require 

accomplishing the actions specified in 

EASA AD 2024–0129 described 

previously, except for any differences 


ddrumheller on DSK120RN23PROD with PROPOSALS1
Federal Register / Vol. 89, No. 189 / Monday, September 30, 2024 / Proposed Rules 79479 

identified as exceptions in the 

regulatory text of this proposed AD. 

Explanation of Required Compliance 

Information 

In the FAA’s ongoing efforts to 

improve the efficiency of the AD 

process, the FAA developed a process to 

use some civil aviation authority (CAA) 

ADs as the primary source of 

information for compliance with 

requirements for corresponding FAA 

ADs. The FAA has been coordinating 

this process with manufacturers and 

CAAs. As a result, the FAA proposes to 

incorporate EASA AD 2024–0129 by 

reference in the FAA final rule. This 

proposed AD would, therefore, requires 

compliance with EASA AD 2024–0129 

in its entirety through that 

incorporation, except for any differences 

identified as exceptions in the 

regulatory text of this proposed AD. 

Using common terms that are the same 

as the heading of a particular section in 

EASA AD 2024–0129 does not mean 

that operators need comply only with 

that section. For example, where the AD 

requirement refers to ‘‘all required 

actions and compliance times,’’ 

compliance with this AD requirement is 

not limited to the section titled 

‘‘Required Action(s) and Compliance 

Time(s)’’ in EASA AD 2024–0129. 

Material required by EASA AD 2024– 

0129 for compliance will be available at 

regulations.gov under Docket No. FAA– 

2024–2320 after the FAA final rule is 

published. 

Costs of Compliance 

The FAA estimates that this AD, if 

adopted as proposed, would affect 28 

airplanes of U.S. registry. The FAA 

estimates the following costs to comply 

with this proposed AD: 

ESTIMATED COSTS FOR REQUIRED ACTIONS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Inspection (cargo door piano hinges) and 

TPS layer check.

1 work-hour × $85 per hour = $85 ................. $0 $85 $2,380 

The FAA has received no definitive 

data on which to base the cost estimates 

for the on-condition actions specified in 

this proposed AD. 

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 

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 

The FAA determined that this 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would 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 this proposed regulation: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Would not affect intrastate 

aviation in Alaska, and 

(3) Would 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 Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 14 CFR part 

39 as follows: 

PART 39—AIRWORTHINESS 

DIRECTIVES 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

Airbus SAS: Docket No. FAA–2024–2320; 

Project Identifier MCAI–2024–00268–T. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by November 

14, 2024. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Airbus SAS Model 

A350–941 and –1041 airplanes, certificated 

in any category, as identified in European 

Union Aviation Safety Agency (EASA) AD 

2024–0129, dated July 5, 2024 (EASA AD 

2024–0129). 

(d) Subject 

Air Transport Association (ATA) of 

America Code 53, Fuselage. 

(e) Unsafe Condition 

This AD was prompted by an updated 

stress analysis on the forward (FWD) cargo 

door and its attachment piano hinges that 

revealed a risk of cracking and crack 

propagation on piano hinges 2 and 3, 

originating from opening-closing fatigue 

cycles of the FWD cargo door. The FAA is 

issuing this AD to address potential failure of 

the piano hinges due to cracking. The unsafe 

condition, if not addressed, could result in 

damage to the FWD cargo door surrounding 

structure and consequent reduced structural 

integrity of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Requirements 

Except as specified in paragraph (h) of this 

AD: Comply with all required actions and 

compliance times specified in, and in 

accordance with, EASA AD 2024–0129. 

(h) Exceptions to EASA AD 2024–0129 

(1) Where EASA AD 2024–0129 refers to 

‘‘16 May 2024 [the effective date of EASA AD 

2024–0098],’’ this AD requires using the 

effective date of this AD. 

(2) Where paragraph (2) of EASA AD 2024– 

0129 specifies ‘‘if, during the DET as required 

by paragraph (1) of this AD, any crack or 

damage is detected, before next flight, contact 

Airbus for approved instructions and, within 

the compliance time specified therein, 


ddrumheller on DSK120RN23PROD with PROPOSALS1
79480 Federal Register / Vol. 89, No. 189 / Monday, September 30, 2024 / Proposed Rules 

accomplish those instructions accordingly,’’ 

this AD requires replacing that text with ‘‘if 

any crack or damage is detected, the crack or 

damage must be repaired before further flight 

using a method approved by the Manager, 

International Validation Branch, FAA; or 

EASA; or Airbus SAS’s EASA Design 

Organization Approval (DOA). If approved by 

the DOA, the approval must include the 

DOA-authorized signature.’’ 

(3) This AD does not adopt the ‘‘Remarks’’ 

section of EASA AD 2024–0129. 

(i) Additional AD Provisions 

The following provisions also apply to this 

AD: 

(1) Alternative Methods of Compliance 

(AMOCs): 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 

responsible Flight Standards Office, as 

appropriate. If sending information directly 

to the manager of the International Validation 

Branch, mail it to the address identified in 

paragraph (j) of this AD. Information may be 

emailed 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. 

(2) Contacting the Manufacturer: For any 

requirement in this AD to obtain instructions 

from a manufacturer, the instructions must 

be accomplished using a method approved 

by the Manager, International Validation 

Branch, FAA; or EASA; or Airbus SAS’s 

EASA Design Organization Approval (DOA). 

If approved by the DOA, the approval must 

include the DOA-authorized signature. 

(3) Required for Compliance (RC): Except 

as required by paragraphs (h)(2) and (i)(2) of 

this AD, if any material referenced in EASA 

AD 2024–0129 contains paragraphs that are 

labeled as RC, the instructions in RC 

paragraphs, including subparagraphs under 

an RC paragraph, must be done to comply 

with this AD; any paragraphs, including 

subparagraphs under those paragraphs, that 

are not identified as RC are recommended. 

The instructions in paragraphs, including 

subparagraphs under those paragraphs, not 

identified as RC may be deviated from using 

accepted methods in accordance with the 

operator’s maintenance or inspection 

program without obtaining approval of an 

AMOC, provided the instructions identified 

as RC can be done and the airplane can be 

put back in an airworthy condition. Any 

substitutions or changes to instructions 

identified as RC require approval of an 

AMOC. 

(j) Additional Information 

For more information about this AD, 

contact Dat Le, Aviation Safety Engineer, 

FAA, 1600 Stewart Avenue, Suite 410, 

Westbury, NY 11590; telephone 516–228– 

7300; email dat.v.le@faa.gov. 

(k) 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 this AD specifies otherwise. 

(i) European Union Aviation Safety Agency 

(EASA) AD 2024–0129, dated July 5, 2024. 

(ii) [Reserved] 

(3) For EASA AD 2024–0129 identified in 

this AD, contact EASA, Konrad-AdenauerUfer 3, 50668 Cologne, Germany; telephone 

+49 221 8999 000; email ADs@

easa.europa.eu; website easa.europa.eu. You 

may find this EASA AD on the EASA website 

at ad.easa.europa.eu. 

(4) You may view this material at the FAA, 

Airworthiness Products Section, Operational 

Safety Branch, 2200 South 216th St., Des 

Moines, WA. For information on the 

availability of this material at the FAA, call 

206–231–3195. 

(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 fr.inspection@nara.gov. 

Issued on September 23, 2024. 

Peter A. White, 

Deputy Director, Integrated Certificate 

Management Division, Aircraft Certification 

Service. 

[FR Doc. 2024–22180 Filed 9–27–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–2322; Project 

Identifier MCAI–2024–00065–Q] 

RIN 2120–AA64 

Airworthiness Directives; THOMMEN 

AIRCRAFT EQUIPMENT AG Digital Air 

Data Computers 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 

certain THOMMEN AIRCRAFT 

EQUIPMENT AG (THOMMEN) AC32 

Digital Air Data Computers. This 

proposed AD results from occurrences 

of AC32 Digital Air Data Computers 

(ADCs) that stop functioning below 

certain temperatures. This proposed AD 

would require replacing an affected 

AC32 Digital ADC with a serviceable 

part. The FAA is proposing this AD to 

address the unsafe condition on these 

products. 

DATES: The FAA must receive comments 

on this NPRM by November 14, 2024. 

ADDRESSES: You may send comments, 

using the procedures found in 14 CFR 

11.43 and 11.45, by any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

regulations.gov. Follow the instructions 

for submitting comments. 

• Fax: (202) 493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue SE, 

Washington, DC 20590. 

• Hand Delivery: Deliver to Mail 

address above between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. 

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 NPRM, the mandatory 

continuing airworthiness information 

(MCAI), any comments received, and 

other information. The street address for 

Docket Operations is listed above. 

Material Incorporated by Reference: 

• For THOMMEN AIRCRAFT 

EQUIPMENT material identified in this 

proposed AD, contact THOMMEN 

AIRCRAFT EQUIPMENT AG, 

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. 

FOR FURTHER INFORMATION CONTACT: 

William Reisenauer, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, 

Suite 410, Westbury, NY 11590; phone: 

(516) 228–7301; email: 9-AVS-AIRBACO-COS@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

The FAA invites you to send any 

written relevant data, views, or 

arguments about this proposal. Send 

your comments to an address listed 

under ADDRESSES. Include ‘‘Docket No. 

FAA–2024–2322; Project Identifier 

MCAI–2024–00065–Q’’ at the beginning 

of your comments. The most helpful 

comments reference a specific portion of 

the proposal, explain the reason for any 

recommended change, and include 

supporting data. The FAA will consider 

all comments received by the closing 

date and may amend this proposal 

because of those comments. 

Except for Confidential Business 

Information (CBI) as described in the 

following paragraph, and other 


ddrumheller on DSK120RN23PROD with PROPOSALS1