Federal Register / Vol. 90, No. 26 / Monday, February 10, 2025 / Rules and Regulations 9207 

Issued on January 21, 2025. 

Suzanne Masterson, 

Deputy Director, Integrated Certificate 

Management Division, Aircraft Certification 

Service. 

[FR Doc. 2025–02395 Filed 2–7–25; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–2023; Project 

Identifier MCAI–2023–01246–T; Amendment 

39–22934; AD 2025–02–01] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier, 

Inc., Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

Bombardier, Inc., Model BD–100–1A10 

airplanes. This AD was prompted by 

uncommanded horizontal stabilizer 

motion during several in-service events 

caused by a problem with the trim 

switch wiring. This AD requires 

installing the pitch/roll trim switch 

relays. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective March 17, 

2025. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of March 17, 2025. 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–2023; 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: 

• For Bombardier material identified 

in this AD, contact Bombardier Business 

Aircraft Customer Response Center, 400 

Coˆte-Vertu Road West, Dorval, Que ́bec 

H4S 1Y9, Canada; phone 514–855–2999; 

email ac.yul@aero.bombardier.com; 

website bombardier.com. 

• 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. 

It is also available at regulations.gov 

under Docket No. FAA–2024–2023. 

FOR FURTHER INFORMATION CONTACT: 

Steven Dzierzynski, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, 

Suite 410, Westbury, NY 11590; 

telephone 516–228–7300; email 9-avsnyaco-cos@faa.gov. 

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 certain Bombardier, Inc., Model 

BD–100–1A10 airplanes. The NPRM 

published in the Federal Register on 

August 21, 2024 (89 FR 67577). The 

NPRM was prompted by AD CF–2023– 

77, dated December 7, 2023, issued by 

Transport Canada, which is the aviation 

authority for Canada (Transport Canada 

AD CF–2023–77) (referred to after this 

as the MCAI). The MCAI states that 

during several in-service events, 

following a STAB TRIM FAULT 

advisory message and an autopilot 

disconnect, both pilot and co-pilot 

commands to trim the horizontal 

stabilizer nose-up resulted in a nosedown movement of the horizontal 

stabilizer. In some events, the horizontal 

stabilizer reached the full travel nosedown position before the crew 

recognized the nature of the problem, 

and quickly recovered control of the 

airplane for safe landing. An issue with 

the trim switch wiring installation was 

identified as the main cause of the inservice unintended horizontal stabilizer 

motion events. The current wiring of the 

system is such that, if trim is enabled 

via the copilot-side trim switch, and the 

pilot-side trim switch malfunctions, it is 

possible for trim to move uncommanded 

or opposite to the intended direction. 

In the NPRM, the FAA proposed to 

require installing the pitch/roll trim 

switch relays. The FAA is issuing this 

AD to address the problem with the trim 

switch wiring, which is the main cause 

of the uncommanded horizontal 

stabilizer motion. The unsafe condition, 

if not addressed, could result in 

increased crew workload and reduced 

safety margins, and if the flightcrew is 

unable to regain control of the 

horizontal stabilizer, would result in 

loss of control of the airplane and high 

control forces. 

You may examine the MCAI in the 

AD docket at regulations.gov under 

Docket No. FAA–2024–2023. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received a comment from an 

individual. The following presents the 

comment received on the NPRM and the 

FAA’s response to that comment. 

Request To Develop a Preventive 

Maintenance Program To Assess 

Affected Airplanes 

The commenter suggested that 

Bombardier should develop a 

preventive maintenance program to 

assess if the proposed AD would apply 

to the same airplanes of different serial 

numbers. The commenter referenced 

another AD (PA–28 wing spar), pointing 

out that operators were only required to 

repair the affected part if damage or 

failure was detected. The commenter 

noted that a preventive replacement of 

the affected part was not required, and 

that is something that Bombardier 

should consider researching. The 

commenter further asserted that this 

would only be considered if engineers 

and researchers can show with evidence 

that periodic inspections outweigh the 

cost of a preventive repair. 

The FAA does not agree. The NPRM 

specifically stated that ‘‘The FAA is 

issuing this NPRM after determining 

that the unsafe condition described 

previously is likely to exist or develop 

on other products of the same type 

design.’’ Bombardier has confirmed that 

airplanes having serial number 20937 

and subsequent, also subject to the 

unsafe condition addressed in this AD, 

were modified in production. Further, 

this AD bypasses any type of preventive 

maintenance inspection prior to 

modifying the trim switches because 

Bombardier has determined that the 

trim switches have a problem with the 

wiring installation, which is why all 

affected trim switches must be rewired 

(not simply inspected and repaired only 

if damage or failure is found). No 

change has been made to this AD in this 

regard. 

Conclusion 

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 

reviewed the relevant data, considered 

the comment received, and determined 

that air safety requires adopting this AD 


ddrumheller on DSK120RN23PROD with RULES1
9208 Federal Register / Vol. 90, No. 26 / Monday, February 10, 2025 / Rules and Regulations 

as proposed. Accordingly, the FAA is 

issuing this AD to address the unsafe 

condition on this product. Except for 

minor editorial changes, 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 Bombardier 

Service Bulletin 100–27–22 and 

Bombardier Service Bulletin 350–27– 

012, both dated December 29, 2022. 

This material specifies procedures to 

install the pitch/roll trim switch relays. 

The installation includes reworking the 

plate assembly; installing relay bracket 

assemblies, relays, ground return stacks 

on the relay bracket assemblies, wires 

for the relays, and line replaceable units 

and trays on the left-side and right-side 

avionic racks; and performing 

operational testing. These documents 

are distinct since they apply to different 

airplane serial numbers. 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. 

Costs of Compliance 

The FAA estimates that this AD 

affects 359 airplanes of U.S. registry. 

The FAA estimates the following costs 

to comply with this AD: 

ESTIMATED COSTS FOR REQUIRED ACTIONS

Labor cost Parts cost Cost per product Cost on U.S. operators 

Up to 45 work-hours × $85 per hour = Up to $3,825 ................. $3,582 Up to $7,407 ............................ Up to $2,659,113. 

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 

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 

■ 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: 

2025–02–01 Bombardier, Inc.: Amendment 

39–22934; Docket No. FAA–2024–2023; 

Project Identifier MCAI–2023–01246–T. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective March 17, 2025. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Bombardier, Inc., 

Model BD–100–1A10 airplanes, certificated 

in any category, serial numbers 20003 

through 20500 inclusive and 20501 through 

20936 inclusive. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 27, Flight controls. 

(e) Unsafe Condition 

This AD was prompted by uncommanded 

horizontal stabilizer motion during several 

in-service events caused by a problem with 

the trim switch wiring. The FAA is issuing 

this AD to address the problem with the trim 

switch wiring. The unsafe condition, if not 

addressed, could result in increased crew 

workload and reduced safety margins, and if 

the flightcrew is unable to regain control of 

the horizontal stabilizer, would result in loss 

of control of the airplane and high control 

forces. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Installation of Pitch/Roll Trim Switch 

Relays and Tests 

Within 3,000 flight hours or 5 years, 

whichever occurs first, from the effective 

date of this AD, install the pitch/roll trim 

switch relays, in accordance with sections 

2.B. and 2.C. of the Accomplishment 

Instructions of the applicable material 

specified in paragraph (g)(1) or (2) of this AD. 

(1) Bombardier Service Bulletin 100–27– 

22, dated December 29, 2022 (for airplane 

serial numbers 20003 through 20500 

inclusive). 

(2) Bombardier Service Bulletin 350–27– 

012, dated December 29, 2022 (for airplane 

serial numbers 20501 through 20936 

inclusive). 

(h) 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 (i) 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 


ddrumheller on DSK120RN23PROD with RULES1
Federal Register / Vol. 90, No. 26 / Monday, February 10, 2025 / Rules and Regulations 9209 

by the Manager, International Validation 

Branch, FAA; or Transport Canada; or 

Bombardier, Inc.’s Transport Canada Design 

Approval Organization (DAO). If approved by 

the DAO, the approval must include the 

DAO-authorized signature. 

(i) Additional Information 

For more information about this AD, 

contact Steven Dzierzynski, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, Suite 

410, Westbury, NY 11590; telephone 516– 

228–7300; email 9-avs-nyaco-cos@faa.gov. 

(j) 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) Bombardier Service Bulletin 100–27–22, 

dated December 29, 2022. 

(ii) Bombardier Service Bulletin 350–27– 

012, dated December 29, 2022. 

(3) For Bombardier material identified in 

this AD, contact Bombardier Business 

Aircraft Customer Response Center, 400 CoˆteVertu Road West, Dorval, Que ́bec H4S 1Y9, 

Canada; phone 514–855–2999; email ac.yul@

aero.bombardier.com; website 

bombardier.com. 

(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 January 16, 2025. 

Victor Wicklund, 

Deputy Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2025–02397 Filed 2–7–25; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–1467; Project 

Identifier AD–2023–01241–T; Amendment 

39–22935; AD 2025–02–02] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for all The 

Boeing Company Model 737–100, –200, 

–200C, –300, –400, and –500 series 

airplanes. This AD was prompted by a 

report indicating cracks in the frame 

inner chord and web at station (STA) 

727. This AD requires an inspection for 

any repair installed, repetitive 

inspections of the frame inner chord 

and web at STA 727 for any crack, and 

applicable on-condition actions. The 

FAA is issuing this AD to address the 

unsafe condition on these products. 

DATES: This AD is effective March 17, 

2025. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of March 17, 2025. 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–1467; 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 Boeing material identified in 

this AD, contact Boeing Commercial 

Airplanes, Attention: Contractual & Data 

Services (C&DS), 2600 Westminster 

Boulevard, MC 110–SK57, Seal Beach, 

CA 90740–5600; telephone 562–797– 

1717; website myboeingfleet.com. 

• You may view this material at the 

FAA, Airworthiness Products Section, 

Operational Safety Branch, 2200 South 

216th Street, Des Moines, WA. For 

information on the availability of this 

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

It is also available at regulations.gov 

under Docket No. FAA–2024–1467. 

FOR FURTHER INFORMATION CONTACT: 

Muoi Vuong, Aviation Safety Engineer, 

FAA, 2200 South 216th Street, Des 

Moines, WA 98198; telephone: 562– 

627–5205; email: Muoi.Vuong@faa.gov. 

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 The Boeing Company Model 

737–100, –200, –200C, –300, –400, and 

–500 series airplanes. The NPRM 

published in the Federal Register on 

May 20, 2024 (89 FR 43792). The NPRM 

was prompted by a report indicating 

cracks in the frame inner chord and web 

at STA 727 between S–11L and S–13L. 

In the NPRM, the FAA proposed to 

require an inspection for any repair 

installed, repetitive inspections of the 

frame inner chord and web at STA 727 

for any crack, and applicable oncondition actions. The FAA is issuing 

this AD to address cracks in the left and 

right frames at STA 727 before they 

reach a critical length. The unsafe 

condition, if not addressed, may result 

in the inability of a principal structural 

element to sustain limit load, which 

could adversely affect the structural 

integrity of the airplane. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

three commenters, including Aviation 

Partners Boeing, FlyPersia Airline, and 

Sudan Civil Aviation Authority. In 

addition, the FAA received a comment 

from an individual whose request is not 

specific to this AD or a request the FAA 

can act on. This comment is outside the 

scope of this rulemaking. The following 

presents the comments received on the 

NPRM and the FAA’s response to each 

comment. 

Effect of Winglets on Accomplishment 

of the Proposed Actions 

Aviation Partners Boeing stated that 

the installation of winglets per the 

Supplemental Type Certificate (STC) 

ST01219SE does not affect the actions 

specified in the proposed AD. 

The FAA agrees with the commenter. 

The FAA has redesignated paragraph (c) 

of the proposed AD as paragraph (c)(1) 

of this AD and added paragraph (c)(2) to 

this AD to state that installation of STC 

ST01219SE does not affect the ability to 

accomplish the actions required by this 

AD. Therefore, for airplanes on which 

STC ST01219SE is installed, a ‘‘change 

in product’’ alternative method of 

compliance (AMOC) approval request is 

not necessary to comply with the 

requirements of 14 CFR 39.17. 

Request To Expand the Area of 

Inspection 

FlyPersia Airline requested that the 

area of inspection for any repair and 

repetitive high frequency eddy current 

inspection include the frame inner 

chord and web at STA 663.75 through 

STA 727 between stringers S–11 and S– 

13 left and right sides. The commenter 

stated that the mentioned crack on 

stringers S–11 and S–13 left and right 

might also exist on those stringers at 

STA 663.75 through STA 727, because 

on Model 737–300 airplanes there is a 

landing gear cavity, which impresses 

circumferential structure unity on STA 

663.75. 


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