Federal Register / Vol. 89, No. 195 / Tuesday, October 8, 2024 / Rules and Regulations 81333 

do corrective actions, and repeat the test 

before further flight until the test passes. 

(l) Parts Installation Prohibition 

As of 60 days from the effective date of this 

AD, it is prohibited to install an LH DCPC 

with P/N 975GC02Y04, 975GC02Y05, 

975GC02Y06, or 975GC02Y07, on any 

airplane. 

(m) Additional AD Provisions 

(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 (n) of this AD. Information may be 

emailed to: 9-AVS-NYACO-COS@faa.gov. 

(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 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. 

(n) 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. 

(o) 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 this AD specifies otherwise. 

(3) The following material was approved 

for IBR on November 12, 2024. 

(i) Bombardier Service Bulletin 100–24–29, 

Revision 01, dated July 27, 2023. 

(ii) Bombardier Service Bulletin 350–24– 

004, Revision 01, dated July 27, 2023. 

(iii) Subject 24–61–01 DC Power Center 

(DCPC)—Removal/Installation, Chapter 24— 

Electrical Power, Bombardier Challenger 300 

Aircraft Maintenance Manual, Part Two, 

Publication No. CH 300 AMM, Revision 82, 

dated November 9, 2023: 

(A) Task 24–61–01–000–801 Removal of 

the DC Power Center (DCPC); 

(B) Task 24–61–01–400–801 Installation 

of the DC Power Center (DCPC); and 

(C) Task 24–61–01–720–801 Functional 

Test of the DC Power Center (DCPC). 

Note 1 to paragraph (o)(3)(iii): For 

obtaining the tasks specified in the 

Bombardier Challenger 300 Aircraft 

Maintenance Manual, Part Two, Publication 

No. CH 300 AMM, use Document 

Identification No. CH 300 AMM. 

(iv) Subject 24–61–01 DC Power Center 

(DCPC)—Removal/Installation, Chapter 24— 

Electrical Power, Bombardier Challenger 350 

Aircraft Maintenance Manual, Part Two, 

Publication No. CH 350 AMM, Revision 38, 

dated November 9, 2023: 

(A) Task 24–61–01–000–801 Removal of 

the DC Power Center (DCPC); 

(B) Task 24–61–01–400–801 Installation 

of the DC Power Center (DCPC); and 

(C) Task 24–61–01–720–801 Functional 

Test of the DC Power Center (DCPC). 

Note 2 to paragraph (o)(3)(iv): For 

obtaining the tasks specified in the 

Bombardier Challenger 350 Aircraft 

Maintenance Manual, Part Two, Publication 

No. CH 350 AMM, use Document 

Identification No. CH 350 AMM. 

(4) The following material was approved 

for IBR on August 15, 2023 (88 FR 44042, 

July 11, 2023). 

(i) Bombardier Service Bulletin 100–24–29, 

dated April 9, 2021. 

(ii) Bombardier Service Bulletin 100–24– 

30, dated November 29, 2022. 

(iii) Bombardier Service Bulletin 350–24– 

004, dated April 9, 2021. 

(iv) Bombardier Service Bulletin 350–24– 

005, dated November 29, 2022. 

(5) For Bombardier material identified in 

this AD, contact Bombardier Business 

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

Canada; telephone 514–855–2999; email 

ac.yul@aero.bombardier.com; website 

bombardier.com. 

(6) 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. 

(7) 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 3, 2024. 

Victor Wicklund, 

Deputy Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2024–23113 Filed 10–7–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–0227; Project 

Identifier MCAI–2023–00886–T; Amendment 

39–22838; AD 2024–18–04] 

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–700–2A12 

airplanes. This AD was prompted by a 

report indicating that the fan in a 

transformer rectifier unit (TRU) can 

become inoperative in a manner that is 

not detectable by the fan monitoring 

circuit. This AD requires replacement of 

the existing TRU Number 2 with a new 

part number that incorporates a 

correction to the fan and the monitoring 

circuit. This AD also prohibits the 

installation of affected parts. The FAA 

is issuing this AD to address the unsafe 

condition on these products. 

DATES: This AD is effective November 

12, 2024. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of November 12, 2024. 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–0227; 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; telephone 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–2024–0227. 

FOR FURTHER INFORMATION CONTACT: 

William Reisenauer, 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–700–2A12 airplanes. The NPRM 

published in the Federal Register on 

February 14, 2024 (89 FR 11228). The 


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81334 Federal Register / Vol. 89, No. 195 / Tuesday, October 8, 2024 / Rules and Regulations 

NPRM was prompted by AD CF–2023– 

53, dated July 14, 2023, issued by 

Transport Canada, which is the aviation 

authority for Canada (referred to after 

this as the MCAI). The MCAI states that 

the fan in a TRU can become 

inoperative in a manner that is not 

detectable by the fan monitoring circuit. 

An inoperative fan leads to higher TRU 

operating temperatures, which can 

trigger the activation of the load shed 

function to reduce the electrical load 

and temperature in the TRU. If the TRU 

temperature continues to rise and 

exceeds the maximum temperature 

threshold, the TRU will automatically 

disconnect. The shed electrical load will 

be transferred to the remaining two 

TRUs, which could lead to overheating 

and cascading failures on the remaining 

TRUs. 

In the NPRM, the FAA proposed to 

require replacement of the existing TRU 

Number 2 with a new part number that 

incorporates a correction to the fan and 

the monitoring circuit. The NPRM also 

proposed to prohibit the installation of 

affected parts. The FAA is issuing this 

AD to address the inability of a TRU to 

detect the fan failure. The unsafe 

condition, if not addressed, could lead 

to overheating and failures on the 

remaining TRUs, which could 

contribute to additional pilot workload 

and adversely affect the safe operation 

of the airplane. 

You may examine the MCAI in the 

AD docket at regulations.gov under 

Docket No. FAA–2024–0227. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

NetJets Inc. The following presents the 

comments received on the NPRM and 

the FAA’s response to the comments. 

Request To Update the Service Bulletin 

to the Latest Revision 

NetJets requested that paragraphs (g) 

and (i) of the proposed AD be revised 

to change Bombardier Service Bulletin 

700–24–7507, Revision 1, dated May 19, 

2023, to Bombardier Service Bulletin 

700–24–7507, Revision 2, dated October 

16, 2023. 

The FAA agrees with the request. For 

airplanes on which the actions of 

Revision 1 of the service bulletin have 

already been done, no more work is 

required by Revision 2. The FAA 

clarified with Bombardier that credit 

can be given for the accomplishment of 

actions specified in Bombardier Service 

Bulletin 700–24–7507, Revision 1, dated 

May 19, 2023. The FAA has therefore 

revised this AD to require Revision 2 

and to add credit in paragraph (i) of this 

AD for accomplishment of the actions 

specified in Bombardier Service 

Bulletin 700–24–7507, Revision 1, dated 

May 19, 2023, if completed before the 

effective date of this AD. 

Request for Allowance To Install Part 

Number G02404521–001 for TRU 

Number 1 and Number 3 

NetJets noted that the Bombardier 

Service Bulletin 700–24–7507, Revision 

2, dated October 16, 2023, limits the 

installation of TRU part number (P/N) 

G02404521–001 to the Number 2 

position. NetJets requested that an 

exception be added to paragraph (h) of 

the proposed AD to also allow the 

installation of TRU P/N G02404521–001 

for TRU Number 1 and TRU Number 3. 

The FAA does not agree to allow 

installation of TRU P/N G02404521–001 

for TRU Number 1 or Number 3. The 

TRU P/N G02404521–001 design fails to 

detect a fan failure. Bombardier Service 

Bulletin 700–24–7507, Revision 2, dated 

October 16, 2023, replaces only TRU 

Number 2 position because it has a 

higher electrical load and is more 

susceptible to the fan inoperative 

condition. TRU P/N G02404521–001 is 

no longer manufactured. The new 

production airplanes are all installed 

with TRU P/N G02404521–003. All 

TRUs that are removed from service 

(e.g., for repair) are upgraded to TRU P/ 

N G02404521–003. Therefore, this AD 

has not been changed regarding this 

request. 

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 

as proposed. Accordingly, the FAA is 

issuing this AD to address the unsafe 

condition on this product. 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 Bombardier 

Service Bulletin 700–24–7507, Revision 

2, dated October 16, 2023. This material 

specifies procedures for replacing the 

existing TRU Number 2 P/N 

G02404521–001 with new P/N 

G02404521–003, including removal of 

the secondary layer of insulation 

blanket ENM386519113C or P/N 

ENM386519113D in front of the TRU 

Number 2 fan air inlet, reidentifying the 

blanket installation by ink stamp, 

checking the electrical bond resistance 

for TRU Number 2, and performing the 

operational test. 

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 56 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 5 work-hours × $85 per hour = Up to $425 .......... Up to $34,754 .................... Up to $35,179 .................... Up to $1,970,024. 

The FAA has included all known 

costs in its cost estimate. According to 

the manufacturer, however, some or all 

the costs of this AD may be covered 

under warranty, thereby reducing the 

cost impact on affected operators. 

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 


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Federal Register / Vol. 89, No. 195 / Tuesday, October 8, 2024 / Rules and Regulations 81335 

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: 

2024–18–04 Bombardier, Inc.: Amendment 

39–22838; Docket No. FAA–2024–0227; 

Project Identifier MCAI–2023–00886–T. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective November 12, 2024. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Bombardier, Inc., 

Model BD–700–2A12 airplanes, certificated 

in any category, serial numbers 70006 

through 70166 inclusive. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 24, Electrical power. 

(e) Unsafe Condition 

This AD was prompted by a report that the 

fan in a transformer rectifier unit (TRU) can 

become inoperative in a manner that is not 

detectable by the fan monitoring circuit. The 

FAA is issuing this AD to address the 

inability of a TRU to detect the fan failure. 

The unsafe condition, if not addressed, could 

lead to overheating and failures on the 

remaining TRUs, which could contribute to 

additional pilot workload and adversely 

affect the safe operation of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Transformer Rectifier Unit (TRU) 

Number 2 Replacement 

Within 1,500 flight hours or 3 years, 

whichever occurs first after the effective date 

of this AD, replace TRU Number 2 part 

number (P/N) G02404521–001 with P/N 

G02404521–003, in accordance with the 

Accomplishment Instructions of Bombardier 

Service Bulletin 700–24–7507, Revision 2, 

dated October 16, 2023. 

(h) Parts Installation Prohibition 

As of the effective date of this AD, no 

person may install, on any airplane, a TRU 

part number G02404521–001. 

(i) Credit for Previous Actions 

This paragraph provides credit for actions 

required by paragraph (g) of this AD, if those 

actions were performed before the effective 

date of this AD using Bombardier Service 

Bulletin 700–24–7507, dated March 31, 2023, 

or Bombardier Service Bulletin 700–24–7507, 

Revision 1, dated May 19, 2023. 

(j) Special Flight Permits 

Special flight permits may be issued in 

accordance with 14 CFR 21.197 and 21.199 

to operate the airplane to a location where 

the actions required by this AD can be 

accomplished, provided no passengers and 

only essential crew are on board, and day 

visual flight rules are used. 

(k) 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 (l)(2) of this AD. Information may 

be emailed to: 9-AVS-NYACO-COS@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 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. 

(l) Additional Information 

(1) For more information about this AD, 

contact William Reisenauer, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, Suite 

410, Westbury, NY 11590; telephone 516– 

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

(2) Material identified in this AD that is not 

incorporated by reference is available at the 

addresses specified in paragraph (m)(3) of 

this AD. 

(m) 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 700–24– 

7507, Revision 2, dated October 16, 2023. 

(ii) [Reserved] 

(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; telephone 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 September 4, 2024. 

Victor Wicklund, 

Deputy Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2024–23115 Filed 10–7–24; 8:45 am] 

BILLING CODE 4910–13–P 


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