97484 Federal Register / Vol. 89, No. 236 / Monday, December 9, 2024 / Rules and Regulations 

(c) Applicability 

This AD applies to The Boeing Company 

Model 767–300F series airplanes, certificated 

in any category, identified as Group 7, 11 

through 15, and 18 in Boeing Special 

Attention Service Bulletin 767–25–0550, 

Revision 2, dated December 18, 2023. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 25, Equipment/Furnishings. 

(e) Unsafe Condition 

This AD was prompted by a determination 

that certain cargo compartment insulation 

blankets do not adequately fit some locations 

and allow smoke to migrate past the cargo 

compartment. The FAA is issuing this AD to 

require replacing these cargo compartment 

insulation blankets. The unsafe condition, if 

not addressed, could result in a fire in the 

bilge area of the cargo compartment, which 

if not contained could lead to a smoke and 

fire event in the passenger compartment. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

Within 36 months after the effective date 

of this AD, do all applicable actions 

identified as ‘‘RC’’ (required for compliance) 

in, and in accordance with, the 

Accomplishment Instructions of Boeing 

Special Attention Service Bulletin 767–25– 

0550, Revision 2, dated December 18, 2023. 

(h) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, AIR–520, Continued 

Operational Safety 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 certification 

office, send it to the attention of the person 

identified in paragraph (i) of this AD. 

Information may be emailed to: AMOC@

faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the responsible Flight Standards Office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair, 

modification, or alteration required by this 

AD if it is approved by The Boeing Company 

Organization Designation Authorization 

(ODA) that has been authorized by the 

Manager, AIR–520, Continued Operational 

Safety Branch, FAA, to make those findings. 

To be approved, the repair method, 

modification deviation, or alteration 

deviation must meet the certification basis of 

the airplane, and the approval must 

specifically refer to this AD. 

(4) FAA AMOC letter 522–24–00097, dated 

March 12, 2024, approved for AD 2021–12– 

11, Amendment 39–21598 (86 FR 33112, 

June 24, 2021) is approved as an AMOC for 

the corresponding provisions of Boeing 

Special Attention Service Bulletin 767–25– 

0550, Revision 2, dated December 18, 2023, 

that are required by paragraph (g) of this AD. 

(5) For service information that contains 

steps that are labeled as Required for 

Compliance (RC), the provisions of 

paragraphs (h)(5)(i) and (ii) of this AD apply. 

(i) The steps labeled as RC, including 

substeps under an RC step and any figures 

identified in an RC step, must be done to 

comply with the AD. If a step or substep is 

labeled ‘‘RC Exempt,’’ then the RC 

requirement is removed from that step or 

substep. An AMOC is required for any 

deviations to RC steps, including substeps 

and identified figures. 

(ii) Steps not labeled 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 RC steps, 

including substeps and identified figures, can 

still be done as specified, and the airplane 

can be put back in an airworthy condition. 

(i) Related Information 

For more information about this AD, 

contact Julie Linn, Aviation Safety Engineer, 

FAA, 2200 South 216th St., Des Moines, WA 

98198; phone: 206–231–3684; email: 

julie.linn@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 the AD specifies otherwise. 

(i) Boeing Special Attention Service 

Bulletin 767–25–0550, Revision 2, dated 

December 18, 2023. 

(ii) [Reserved] 

(3) For Boeing material identified in this 

AD, contact Boeing Commercial Airplanes, 

Attention: Contractual & Data Services 

(C&DS), 2600 Westminster Blvd., MC 110– 

SK57, Seal Beach, CA 90740–5600; telephone 

562–797–1717; website myboeingfleet.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 November 20, 2024. 

Peter A. White, 

Deputy Director, Integrated Certificate 

Management Division, Aircraft Certification 

Service. 

[FR Doc. 2024–28781 Filed 12–6–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2023–2403; Project 

Identifier AD–2023–00888–T; Amendment 

39–22893; AD 2024–24–03] 

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 certain 

The Boeing Company Model MD–11 

and MD–11F airplanes. This AD was 

prompted by a report of a Model MD– 

11F airplane experiencing an 

uncommanded deployment of a thrust 

reverser in flight at low altitude. This 

AD requires initial and repetitive 

detailed inspections and repetitive wire 

integrity tests of the engine pylon thrust 

reverser control system wire harnesses, 

junction box assembly and junction box 

cover, left-side and right-side thrust 

reverser electrical harnesses, core 

(engine compartment) miscellaneous 

wire harness assembly, and 30-degree 

bulkhead wire harness assembly; and 

applicable on-condition actions. This 

AD also requires reporting inspection 

results. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective January 13, 

2025. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of January 13, 2025 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2023–2403; 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 

Blvd., MC 110–SK57, Seal Beach, CA 

90740–5600; telephone 562–797–1717; 

website myboeingfleet.com. 


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• 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–2023–2403. 

FOR FURTHER INFORMATION CONTACT: Tak 

Kobayashi, Aviation Safety Engineer, 

FAA, 2200 South 216th St., Des Moines, 

WA 98198; telephone 206–231–3553; 

email takahisa.kobayashi@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 The Boeing Company 

Model MD–11 and MD–11F airplanes 

equipped with General Electric (GE) 

CF6–80C2D1F high-bypass turbofan 

engines. The NPRM published in the 

Federal Register on December 29, 2023 

(88 FR 90134). The NPRM was 

prompted by a report of a Model MD– 

11F airplane equipped with three GE 

CF6–80C2D1F high-bypass turbofan 

engines experiencing an uncommanded 

deployment of a thrust reverser in flight 

at low altitude. In the NPRM, the FAA 

proposed to require a one-time detailed 

inspection of the engine pylon thrust 

reverser control system wire harnesses; 

repetitive detailed inspections and wire 

integrity tests of the engine pylon thrust 

reverser control system wire harnesses, 

junction box assembly and junction box 

cover, left-side and right-side thrust 

reverser electrical harnesses, core 

(engine compartment) miscellaneous 

wire harness assembly, and 30-degree 

bulkhead wire harness assembly; and 

applicable on-condition actions. The 

FAA also proposed to require reporting 

inspection results. The FAA is issuing 

this AD to address uncommanded 

deployment of a thrust reverser in flight 

at low altitude, which could result in 

loss of flight control of the airplane and 

loss of continued safe flight and 

landing. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received a comment from 

the Air Line Pilots Association, 

International (ALPA), who supported 

the NPRM without change. 

The FAA received additional 

comments from five commenters, 

including Boeing, FedEx Express 

(FedEx), United Parcel Service (UPS), 

and two individuals. The following 

presents the comments received on the 

NPRM and the FAA’s response to each 

comment. 

Request To Delete an Incorrect Location 

Boeing requested that the FAA delete 

the text ‘‘(in the pylon)’’ in the 

Summary and Material Incorporated by 

Reference under 1 CFR part 51 section 

of the NPRM. Boeing explained that the 

text ‘‘(in the pylon)’’ implies that the 

wire integrity tests shall be applied only 

to the pylon wiring as part of the 

repetitive wire integrity tests. Boeing 

stated that these tests also apply to the 

engine pylon thrust reverser control 

system wiring from the nose of the 

airplane. 

The FAA agrees with the request. 

While a detailed inspection is 

performed on the wire harnesses in the 

pylon, the location for performing the 

wire integrity tests of the engine pylon 

thrust reverser control system wire 

harnesses is not limited to the pylon. 

The FAA has deleted the text ‘‘(in the 

pylon)’’ in this final rule accordingly. 

Concern for the Workability of the 

Service Bulletin 

FedEx expressed their concern 

regarding the workability of Boeing 

Alert Service Bulletin MD11–78A017, 

dated December 4, 2023. FedEx stated 

that a prime example of complexity in 

Work Package 2 of Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023, is Part 19, which 

requires actions to be concurrently 

performed on the left and right thrust 

reverser halves, instead of having two 

separate PARTs to perform required 

actions on each thrust reverser half 

independently from the other thrust 

reverser half. This results in the need to 

evaluate four possible conditions of the 

wire harnesses on the left and right 

thrust reverser halves. The commenter 

stated that due to complexity of the 

service bulletin as well as the sheer 

scope of the work being performed, a 

significant risk exists for introducing 

human errors during the 

accomplishment of the required work. 

The FAA recognizes that the work 

instructions provided in this service 

bulletin are extensive and complex. 

Boeing Alert Service Bulletin MD11– 

78A017, dated December 4, 2023, was 

revised to Revision 1, dated June 4, 

2024, to correct errors and improve 

clarity. The FAA reviewed Revision 1 of 

the service bulletin and determined it 

provides adequate information. 

Although the work instructions 

provided in the original and revised 

service bulletins are extensive and 

complex, the actions specified in the 

service bulletin that is required by this 

AD are necessary to address the unsafe 

condition. This AD mandates Boeing 

Alert Service Bulletin MD11–78A017, 

Revision 1, dated June 4, 2024, and 

provides credit for actions 

accomplished before the effective date 

of this AD using Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023. In addition, the 

exception in paragraph (h)(2) of the 

proposed AD was addressed and 

corrected in Revision 1 of the service 

bulletin; therefore, paragraph (h)(2) of 

the proposed AD was removed from this 

AD. The current instructions in Boeing 

Alert Service Bulletin MD11–78A017, 

dated December 4, 2023, and Revision 1, 

dated June 4, 2024, can be followed 

without any major issue that would 

prevent accomplishment of the required 

actions. Further, additional actions in 

the revised service bulletin are intended 

for best maintenance practice and not 

necessary to address the unsafe 

condition. Those additional actions 

include the detailed inspection of the 

junction box assembly for any loose 

electrical connection in Step 1, Part 10, 

and application of torque to any loose 

electrical connection in Step 2, Part 11 

of the revised service bulletin. 

Therefore, those parts in either the 

original or Revision 1 of the service 

bulletin are acceptable for compliance 

with the AD. For clarity, the FAA added 

a new exception to paragraph (h) of this 

AD specifying the added steps in 

Revision 1 of the service bulletin are not 

required for compliance with the AD. 

Request To Remove Work Package 2 

FedEx stated that Work Package 2 in 

Boeing Alert Service Bulletin MD11– 

78A017, dated December 4, 2023, is too 

broad in scope, and not supported or 

warranted by the results of the 

investigation. FedEx stated that a third 

protection feature to prevent in-flight 

thrust reverser deployment is not 

required for Model MD–11 airplanes 

since it was predicted that the airplane 

will be controllable with the thrust 

reverser deployed in air. FedEx stated 

that the outcome of the service event 

has served to validate this prediction. 

FedEx further stated that damaged wire 

bundles and grounds in the pylon 

discovered on the event airplane could 

have allowed energization of the 

pressure regulator shutoff valve 

(PRSOV) and directional pilot valve 

(DPV), which could result in in-flight 

thrust reverser deployment. No other 

element that could have contributed to 

the event was found by the 

investigation. Finally, FedEx stated that 

the actions in Work Package 2 will 

disturb the areas that are not routinely 

disturbed and therefore could introduce 

unintended consequences. FedEx added 


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1The words ‘‘ground’’ and ‘‘shield’’ may be used 

interchangeably in Boeing’s documents. 

that to properly accomplish Work 

Package 2, it is necessary to expend 

significant resources to deal with the 

complexity and extent of the 

requirements, including training of 

personnel. 

The FAA does not agree with the 

request. The FAA infers that FedEx is 

requesting that Work Package 2 be 

removed from the requirements of the 

AD. Although the event airplane was 

safely brought back to the ground after 

in-flight uncommanded thrust reverser 

deployment, this does not suggest that 

Model MD–11 airplanes will be 

controllable under any anticipated 

operating condition with the thrust 

reverser deployed in air. Model MD–11 

airplanes have not been demonstrated 

for their controllability when the 

deployment of single or dual thrust 

reverser halves is encountered on any 

single engine at low altitudes under 

anticipated operating conditions. The 

wiring damage discovered in the pylon 

of the event airplane was for the PRSOV 

and DPV circuits, and the manufacturer 

concluded that this damage was a 

contributing factor to the event. 

However, it is unclear what conditions 

resulted in power-to-power short— 

instead of power-to-ground 1 (shield), 

which would not result in 

uncommanded thrust reverser 

deployment. Based on available data, it 

is likely that a combination of 

conditions needs to be encountered to 

result in uncommanded thrust reverser 

deployment. Considering the age of the 

affected fleet, undetected degradation in 

wiring installation could have 

contributed to the event. Such a latent 

wiring anomaly could make an airplane 

vulnerable to a single failure that would 

impose a significant risk. Work Package 

1 requires inspections of wiring in the 

pylon to detect any damage, and this 

action is intended to eliminate any 

similar condition discovered on the 

event airplane in a quick and practical 

manner. Work Package 2 requires wire 

integrity tests in addition to inspections 

of various wiring harnesses, and those 

actions are necessary to prevent and 

detect a potential latent anomalous 

condition of wiring installation. The 

FAA agrees that those actions are 

extensive, and the areas affected by the 

required actions are not routinely 

disturbed. However, in the FAA’s 

assessment, Work Package 2 (which 

specifies the same substantive 

requirements in both the original issue 

and Revision 1 of Boeing Alert Service 

Bulletin MD11–78A017) is appropriate 

and necessary to understand and 

eliminate the root cause of the event, 

and the cost of any additional 

‘‘significant resources’’ necessary to 

accomplish those actions would be 

outweighed by the safety benefits of the 

AD. This AD has not been changed 

regarding this request. 

Request To Remove the Inspection 

Requirement for the Junction Box 

Assembly in Work Package 2 

FedEx requested that the FAA remove 

the inspection requirement for the 

junction box assembly included in Work 

Package 2 in Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023. FedEx stated that no 

chafed or burnt wires were found inside 

the junction box assembly of the event 

airplane or on numerous units 

examined as part of investigations. 

FedEx stated that removal of the 

junction box assembly for inspection 

will increase the risk of damage to the 

junction box assembly and surrounding 

wire harnesses. 

The FAA does not agree with the 

request. Although the event airplane did 

not reveal any evidence directly linked 

to the PRSOV and DPV system wiring 

inside the junction box assembly, 

damage to those wires inside the 

junction box assembly could result in 

the same outcome encountered on the 

event airplane. The junction box 

assembly is a high-density area of wire 

routing, where wires with power are 

routed with the thrust reverser control 

wires. The inspection of the junction 

box assembly is intended to detect and 

eliminate any riding condition of wires 

since such condition could damage the 

thrust reverser control wires. The FAA 

does not have any data regarding the 

other units investigated. These units are 

subject to the same unsafe condition 

because of their similar design and 

installation. This AD has not been 

changed regarding this request. 

Request To Remove the Required 

Actions on Engine 2 

FedEx requested that the required 

actions on engine 2 (tail-mounted 

engine) be removed from the proposed 

AD. The commenter stated that in-flight 

deployment of a thrust reverser of 

engine 2 will have considerably less 

impact on controllability of the airplane 

than the wing-mounted engine 1 and 

engine 3. The commenter stated that 

wiring running through the wings and 

attaching structures are far more 

exposed to vibration and variable 

loading than those in the more stable 

tail structure. Because of the less harsh 

operating environment for engine 2, 

combined with the historical reliability 

and a lack of wire damage findings in 

the tail thrust reverser, FedEx 

concluded that the required actions on 

the engine are not justified. 

The FAA does not agree with the 

request. As discussed earlier, Model 

MD–11 airplanes have not been 

demonstrated for their controllability 

when the deployment of single or dual 

thrust reverser halves is encountered on 

any single engine at low altitudes under 

anticipated operating conditions. 

Therefore, prevention of in-flight thrust 

reverser deployment is as critical for the 

tail-mounted engines as the wingmounted engines. Also, routing of wire 

harnesses is not the same for the tailmounted engines and wing-mounted 

engines as the wire routing is restricted 

by available space. Vibration is a factor 

that could contribute to wire chafing 

damage, but that is not the only factor. 

Available gaps between wire harnesses 

and surrounding structure as well as the 

types of wire support could also 

contribute to wire chafing damage. 

Therefore, an inspection of all engines, 

including engine 2, is critical and 

necessary. This AD has not been 

changed regarding this request. 

Concern for Economic Impact 

FedEx stated that the FAA 

considerably underestimated the 

economic impact to operators. FedEx 

claimed that the estimated costs in the 

NPRM completely ignored the expense 

of acquiring contingency material. Even 

if the inspections do not identify any 

out-of-limit conditions, operators must 

still be prepared for the eventuality of 

findings to prevent the possibility of 

extended grounding of airplanes. 

Preliminary attempts to acquire 

necessary spare materials have revealed 

little or no global supply. Boeing has not 

provided firm timelines for making 

spare materials available and pricing for 

this commitment. FedEx concluded 

that, because pricing has not been 

provided, it has not been correctly 

incorporated in the cost estimate of the 

NPRM. 

The FAA acknowledges FedEx’s 

concern but does not agree with the 

request. As explained in the NPRM, the 

FAA did not receive definitive data that 

would enable the FAA to provide a 

labor and parts cost estimate for the oncondition repairs or replacements. With 

regards to necessary parts, the 

manufacturer has been addressing this 

issue, and the FAA has concluded that 

the necessary spare materials would be 

available. To the extent spare parts may 

not exist to replace parts that fail the 

inspection requirements of this AD, the 

FAA cannot base its AD action on 

whether spare parts are available or can 

be produced. While every effort is made 


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to avoid grounding aircraft, the FAA 

must address the unsafe condition. 

However, if parts availability becomes a 

problem during compliance with the AD 

requirements, operators may request 

approval of an extension of the 

compliance time as an alternative 

method of compliance (AMOC) in 

accordance with the procedures 

specified in paragraph (k) of this AD, if 

the operator submits sufficient data to 

substantiate that an acceptable level of 

safety would be provided with such an 

extension. This AD has not been 

changed regarding this request. 

Request for More Economical Solution 

One individual requested that the 

FAA consider alternatives that could 

reduce the operational/economic 

burden on operators. 

The commenter did not propose any 

alternative approach to addressing the 

unsafe condition. In developing the 

most appropriate solution, the FAA 

considered the recommendations of the 

manufacturer, the urgency associated 

with the unsafe condition, the 

availability of required parts, and the 

practical aspect of accomplishing the 

required actions within a period of time 

that corresponds to the normal 

scheduled maintenance for most 

affected operators. The FAA has 

determined that the cost to operators to 

comply with this AD, as proposed, is 

outweighed by the safety benefits. 

Requests To Change Parts Necessary for 

Each Airplane Section in Service 

Bulletin 

FedEx requested revision of the parts 

necessary for each airplane section in 

Boeing Alert Service Bulletin MD11– 

78A017, dated December 4, 2023, to 

make it workable. The commenter stated 

that the information provided in Boeing 

Alert Service Bulletin MD11–78A017, 

dated December 4, 2023, regarding parts 

necessary for each airplane is 

incomplete and insufficient for 

operators to effectively plan for the 

execution of the service bulletin 

requirements. The commenter stated 

that determining part numbers 

necessary for accomplishing the 

required action by researching Boeing 

documents should not fall under the 

operator’s responsibility. The service 

bulletin provides an option of repair, 

but it will still require identification and 

availability of specific wire and related 

electrical components. The commenter 

stated that all part numbers of 

potentially affected assemblies and 

components would need to be identified 

in the service bulletin, or the materials 

necessary for repair would need to be 

available for procurement. 

Similarly, UPS requested a 

comprehensive parts list in Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, as well as a source 

of suitable available spares, prior to the 

implementation of the AD. UPS added 

that the components such as wiring and 

connectors are out of production, and 

available parts are limited. UPS 

requested that the AD be delayed until 

a suitable parts list and spare source are 

determined. 

The FAA does not agree with the 

requests. Regarding the parts 

information provided in the service 

bulletin, the manufacturer anticipated 

that new replacement parts for full wire 

harnesses or junction box assemblies 

would not be available from suppliers. 

Therefore, a repair would be the only 

available option to address damaged or 

failed parts, unless serviceable parts 

removed from an airplane are installed 

as replacement parts for an affected 

airplane. As stated previously, if parts 

availability becomes a problem during 

compliance with the AD requirements, 

an operator may request approval of an 

extension of the compliance time as an 

AMOC in accordance with the 

procedures specified in paragraph (k) of 

this AD, if the operator submits 

sufficient data to substantiate that an 

acceptable level of safety would be 

provided with such an extension. The 

intent of the service bulletin was to 

provide sufficient information necessary 

to accomplish required actions instead 

of providing full details of all parts 

since providing such information for all 

wiring configurations would require a 

substantial amount of time for this 

urgent issue and may further complicate 

the service bulletin. Based on the 

information provided in the service 

bulletin and available documents, such 

as wiring diagrams, the illustrated parts 

catalog, and drawings, the operators 

should be able to determine the 

necessary parts for repairs. The 

manufacturer confirmed that they 

would support operators to confirm the 

necessary parts for accomplishing the 

required actions. This AD has not been 

changed regarding this request. 

Request To Add an Instruction for a 

Condition With Multiple Options 

FedEx requested that an instruction 

be added in the AD regarding how a 

required condition should be handled 

when the condition provides multiple 

options. The commenter stated that 

instructions identified as required for 

compliance (RC) are also identified as 

an option that is contingent on certain 

conditions being met and a choice being 

made by the operator. The commenter 

expressed a concern that if this is not 

directly addressed in the language of the 

AD, it is anticipated that these RC 

options will be difficult to deal with 

when maintenance work cards are 

generated, putting the technicians in the 

position of making a choice to sign off 

an AD-required step as not applicable 

for the option not taken. 

The FAA does not agree with the 

comment. In addition to Section 1.E., 

Compliance, of Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023, or Revision 1, dated 

June 4, 2024, Note 13 in Section 3.A. of 

the service bulletin provides the 

instruction on how to handle a required 

condition when multiple options are 

provided under that condition. This 

instruction provided by a general note 

has been used in numerous service 

bulletins and is not unique to this 

specific service bulletin. Therefore, it is 

unnecessary to repeat this instruction in 

the AD. No further changes have been 

made to this AD regarding this request. 

Request To Provide Instructions for 

Insulation Resistance Test 

FedEx stated that Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023, does not provide 

sufficient detail to ensure that wire 

harness insulation resistance checks in 

Parts 6 through 8 in the service bulletin 

are performed properly. The commenter 

recommended including a statement 

that each of the checks should be 

measured against ground. The 

commenter also stated that unless 

precautionary or explanatory statements 

are included to indicate application of 

500V between the pins and each of the 

other contacts on the same connector 

may damage other components on the 

circuit, uncertainty around validating 

the test may result. 

The FAA does not agree with the 

request. The insulation resistance check 

is a standard practice. The operators are 

expected to follow applicable 

instructions in the standard wiring 

practice manual to perform the test for 

the connectors specified in the service 

bulletin. The test requirement is to 

measure between every pin and ground 

(shielding) and between all two adjacent 

pins. This AD has not been changed 

regarding this request. 

Request for Additional Details in Part 

19 in the Service Bulletin 

FedEx stated that the instructions for 

Part 19 in Boeing Alert Service Bulletin 

MD11–78A017, dated December 4, 

2023, are too vague since the specific 

connectors and pins are not identified. 

FedEx added that Boeing does not have 

adequate data to specify the detail since 

the harnesses to be tested are not 


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controlled by Boeing. This lack of detail 

places the burden onto the operators to 

ensure that the tests are performed as 

intended. The commenter does not 

believe the instructions in the service 

bulletin are adequate to ensure 

successful compliance. 

The FAA does not agree with the 

request. As the commenter stated, the 

manufacturer does not have the details 

of the pins or connectors, as the data for 

the wire harnesses is not controlled by 

Boeing. Further, due to the urgency of 

the unsafe condition, the FAA cannot 

delay issuance of this final rule further 

for Boeing to identify the connectors or 

pins. This will place the burden on the 

operators, but the operators should 

utilize available data and ensure that the 

tests are performed adequately based on 

input provided by the manufacturer. 

This AD has not been changed regarding 

this request. 

Request To Revise the Work 

Instructions for Part 13 in the Service 

Bulletin 

FedEx requested revision of the work 

instructions in Part 13 of Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, which requires an 

inspection of the internal surface of the 

junction box cover per Figure 13 for 

burn marks, signs of arcing, and fretting. 

The commenter stated that many 

inspected junction boxes’ covers 

exhibited smudges and discoloration 

that can be misinterpreted as soot and 

burn residual, rather than the dust from 

the harness lacings rubbing against the 

cover. The instructions as currently 

written may result in many false 

findings. The commenter requested that 

a note be added to the service bulletin 

to call attention to the possibility of the 

benign discoloration and allow for the 

presence of such residue. 

The FAA partially agrees with the 

request. The FAA agrees that the work 

instructions in Part 13 of Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, may result in false 

findings. However, this AD will require 

Revision 1 of the service bulletin. The 

work instructions in Part 13 of Boeing 

Alert Service Bulletin MD11–78A017, 

Revision 1, dated June 4, 2024, have 

been updated to eliminate the potential 

misinterpretation of the conditions 

found on the junction box cover during 

the inspection. No change to this AD 

has been made as a result of this 

comment. 

Request To Revise Figures 14 and 15 in 

the Service Bulletin 

FedEx requested that Figures 14 and 

15 of Boeing Alert Service Bulletin 

MD11–78A017, dated December 4, 

2023, be revised to remove the 

minimum clearance requirement 

between the wire harnesses and the 

junction box cover or to add a 

clarification stating that contact between 

the junction box cover and lacing 

material is acceptable. In the alternative, 

FedEx asked that the language of the 

proposed AD be revised to add an 

exemption to the minimum clearance 

requirement in paragraph (h) of the 

proposed AD. The commenter noted 

that Parts 14 and 15 of the service 

bulletin require a minimum clearance of 

0.20 inch between the junction box 

cover and the wire bundles inside the 

junction box assembly. However, there 

is no instruction to confirm that this 

minimum clearance is maintained when 

the junction box cover is closed. The 

commenter stated that the wire 

harnesses inside the junction box 

assembly are very stiff and rigid and 

generally cannot be appreciably 

compacted. Although this condition 

may result in minor interference of the 

lacings with the cover, the commenter 

has not found any evidence of wire 

damage resulting from this contact. 

The FAA partially agrees with the 

request. The FAA agrees that the 

instructions to achieve the required 

minimum clearance were unclear in 

Boeing Alert Service Bulletin MD11– 

78A017, dated December 4, 2023. The 

work instructions have been revised in 

Boeing Alert Service Bulletin MD11– 

78A017, Revision 1, dated June 4, 2024, 

for clarification. However, Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, or Revision 1, dated 

June 4, 2024, does not allow contact 

between the junction box cover and 

lacing material since such a condition 

may eventually result in wire damage. 

No change has been made to this AD as 

a result of this comment. 

Request To Correct Typographical 

Errors 

FedEx noted multiple errors and 

typographical errors in Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, and requested 

revision of the service bulletin to correct 

these errors and typographical errors. 

The errors and typographical errors 

identified by the commenter have been 

corrected in Boeing Alert Service 

Bulletin MD11–78A017, Revision 1, 

dated June 4, 2024, which is the primary 

source of service information in this AD. 

No change has been made to this AD as 

a result of this comment. 

Request To Revise the Compliance 

Time of the Reporting Requirement 

FedEx requested revision of the 

compliance time of the reporting 

requirement in paragraph (i) of the 

proposed AD. The commenter stated 

that the proposed compliance time of 30 

days is inadequate to prepare the data 

package and submit the reports. The 

commenter stated they do not 

understand the urgency of the reporting 

requirement considering the overall 

compliance span of the AD. 

The FAA agrees that the proposed 

compliance time of 30 days for the 

reporting requirement is unnecessarily 

short considering the burden on the 

operators and the intent that those 

reports will be used for root cause 

assessment while managing the 

potential risk by the inspections. The 

FAA has revised the compliance time of 

paragraph (i) of this AD to 90 days 

accordingly. 

Request To Change Reporting 

Requirements 

FedEx requested that the FAA 

eliminate the reporting requirement of 

paragraph (i) of the proposed AD or 

revise the requirements to clarify what 

must be reported to meet the 

compliance criteria. The commenter 

was concerned that the reporting criteria 

in the service bulletin are open-ended 

and could be misinterpreted as to what 

qualifies as reportable and what level of 

detail is required. The commenter stated 

that because of the breadth of the 

reporting criteria involved, it would be 

extremely hard to definitively comply 

with the reporting requirement. Also, 

the commenter stated that the 

relationship between Boeing and the 

operators should be sufficient to ensure 

that findings will be provided to Boeing 

without a mandatory reporting 

requirement. 

The FAA partially agrees with the 

request. 

The FAA agrees to revise the 

reporting criteria for clarification so that 

the results of the inspections or tests are 

reported in a consistent manner. The 

reporting form in Appendix C of the 

original service bulletin was updated in 

Boeing Alert Service Bulletin MD11– 

78A017, Revision 1, dated June 4, 2024. 

The updated reporting forms in 

Appendixes C through E of Boeing Alert 

Service Bulletin MD11–78A017, 

Revision 1, dated June 4, 2024, provide 

clear instructions to address the concern 

expressed by the commenter. 

The FAA disagrees, however, with the 

request to remove the reporting 

requirement in paragraph (i) of this AD. 

The findings provided by the reports 

will be used for the root cause 

assessment and the development of a 

final corrective action. Therefore, the 

reporting requirement is a critical piece 

of this interim action AD. 


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Request To Use Boeing Service Bulletin 

as an Optional Inspection 

UPS requested that the actions 

specified in Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023, remain as an optional 

inspection until the root cause can be 

determined. 

The FAA does not agree with the 

request. As discussed in the preamble of 

the NPRM, wiring damage was found in 

the engine pylon of the event airplane. 

The root cause of uncommanded thrust 

reverser deployment has not been 

determined yet, but the manufacturer 

concluded that wiring damage was a 

contributing factor of the event based on 

the assessment of on-wing data and 

laboratory inspection. The FAA 

considers this AD to be an interim 

action. The FAA issues an interim 

action AD when, for example, an unsafe 

condition that requires a mitigating 

action relatively quickly is identified on 

airplanes, but the root cause leading to 

the unsafe condition is still 

undetermined due to limited available 

data. In this case, the interim mitigating 

action is needed to address the overall 

risk of the unsafe condition. Based on 

the FAA’s assessment, the actions 

required by this AD would mitigate the 

unsafe condition in the interim period 

while additional inspection data would 

allow the manufacturer to determine the 

root cause and develop an adequate 

corrective action. This AD has not been 

changed regarding this request. 

Request To Delay Issuance of Final 

Rule 

UPS requested that the effective date 

of the AD be extended until Boeing 

Alert Service Bulletin MD11–78A017 is 

revised. UPS stated that Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, identified in the 

NPRM is unworkable due to 

discrepancies and disagreements 

between the configurations specified in 

the instructions and the actual 

installation. 

Because this AD has been changed to 

mandate Boeing Alert Service Bulletin 

MD11–78A017, Revision 1, dated June 

4, 2024, which clarifies these 

instructions, no further change is 

necessary to this AD as a result of this 

comment. The manufacturer also 

worked with the operators to ensure that 

the work instructions in Revision 1 can 

be accomplished. This AD has not been 

changed regarding this request. 

Request To Extend the Compliance 

Time for Work Package 1 and Increase 

Labor Hours 

UPS requested that the FAA revise 

paragraph (h) of the proposed AD to 

extend the compliance time of Work 

Package 1 of Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023, to 27 months from 

the current proposal of 12 months. UPS 

stated that the labor estimate provided 

in the service bulletin underestimates 

the tasks involved in Work Package 1. 

UPS estimated that about 700 workhours would be involved, while Boeing 

Alert Service Bulletin MD11–78A017, 

dated December 4, 2023, estimated 

134.25 hours. Considering extensive 

work-hours and limited parts 

availability, UPS stated that the 

proposed compliance time of 12 months 

does not provide sufficient time to 

accomplish the required actions for the 

affected fleet. 

The FAA does not agree with the 

request. The FAA infers that the labor 

estimates provided by UPS include the 

labor necessary for repairs. The labor 

estimates provided in the service 

bulletin do not include the labor 

necessary for repairs since a repair is an 

on-condition action that would be 

affected by the extent of the damage 

discovered on the affected parts. The 

FAA recognizes that a gap would exist 

between the estimates provided in the 

service bulletin and the actual labor 

needed for each airplane because of 

those on-condition actions. The FAA 

established the compliance time so that 

operators can accomplish this interim 

mitigation action in a quick and 

practical manner, considering the 

potential effect of the unsafe condition. 

The FAA also assessed parts availability 

and necessary labor and determined that 

the compliance time of 12 months 

would be appropriate for Work Package 

1. Operators can request approval of an 

extension of the compliance time in 

accordance with paragraph (k) of this 

AD if operators can provide the 

evidence that would make the required 

compliance time impractical and 

justification for maintaining an 

acceptable level safety with such an 

extension. This AD has not been 

changed regarding these requests. 

Request To Include Spare Engines and 

Thrust Reversers in Applicability 

UPS requested that paragraph (c) of 

the proposed AD be revised to include 

spare engines and thrust reversers in the 

AD applicability. Although Boeing Alert 

Service Bulletin MD11–78A017, dated 

December 4, 2023, requires inspections 

and repair of the components for the 

engines and thrust reversers, an engine 

or thrust reverser on which the actions 

of Boeing Alert Service Bulletin MD11– 

78A017, dated December 4, 2023, were 

accomplished may be replaced with an 

engine or thrust reverser on which the 

actions specified in Boeing Alert Service 

Bulletin MD11–78A017, dated 

December 4, 2023, have not been 

accomplished. 

The FAA disagrees with the request. 

The FAA understands the concern of an 

AD-compliant engine or thrust reverser 

being inadvertently replaced with a 

non-AD-compliant engine or thrust 

reverser. However, the AD is issued to 

address the unsafe condition identified 

at the airplane level. The affected 

airplanes must be maintained in the ADcompliant configuration once each 

airplane is demonstrated to be 

compliant with the AD. Installing an 

engine or thrust reverser that has not 

been inspected or tested as required by 

this AD on an airplane that was 

demonstrated to be compliant with the 

AD is not allowed since such an action 

will bring the airplane back to a nonAD-compliant configuration, unless the 

engine or thrust reverser is inspected or 

tested as required by the AD prior to 

returning the airplane back to service. It 

is the operator’s responsibility to 

maintain each airplane in the ADcompliant configuration. This AD has 

not been changed regarding this request. 

Request for a Specific Interval 

Inspection 

An individual commenter 

recommended that the FAA analyze the 

frequency of the occurrence of 

uncommanded thrust reverser 

deployment in air and determine a 

specific interval for this inspection. 

Although the FAA agrees with the 

intent behind this request, it is not 

necessary to change the AD based on 

this request. The FAA already assessed 

the aspect the commenter raised. The 

FAA has assessed the risk of in-flight 

thrust reverser deployment, considering 

the frequency of occurrence based on 

available data, and determined that the 

compliance times for the initial and 

repetitive inspections are adequate. As 

discussed in the preamble of the NPRM, 

the actions required by this AD are 

considered an interim action. 

Additional data to be provided by the 

operators through the reporting 

requirement of this AD will enable the 

manufacturer to obtain better insight 

into the potential conditions that led to 

the event. Based on the information 

provided by those reports, the FAA may 

consider further rulemaking. 

Conclusion 

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 


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97490 Federal Register / Vol. 89, No. 236 / Monday, December 9, 2024 / Rules and Regulations 

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 Boeing Alert 

Service Bulletin MD11–78A017, 

Revision 1, dated June 4, 2024. This 

material specifies Work Package 1 

inspection procedures to do an initial 

detailed inspection of the engine 1, 

engine 2, and engine 3 pylon thrust 

reverser control system wire harnesses. 

The material also specifies Work 

Package 2 procedures to do repetitive 

detailed inspections and wire integrity 

tests at the following locations: engine 

1, engine 2, and engine 3 thrust reverser 

control system wire harnesses; junction 

box assembly and junction box cover 

(only detailed inspection); left side and 

right side thrust reverser electrical 

harnesses; core (engine compartment) 

miscellaneous wire harness assembly; 

and 30-degree bulkhead wire harness 

assembly. The material also specifies 

applicable on-condition actions 

(including repairs, replacements, 

installations, post-replacement 

inspections and tests, and return to 

service tests). The material also specifies 

that accomplishing the initial 

inspections and tests by doing Action 1 

through Action 3 in Work Package 2 

terminates the need to do the inspection 

in accordance with Part 2 as required in 

Work Package 1. However, this 

substitution of actions does not change 

the compliance time of Work Package 1 

as specified in Table 1 of paragraph 1.E., 

‘‘Compliance,’’ of Boeing Alert Service 

Bulletin MD11–78A017, Revision 1, 

dated June 4, 2024. 

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. 

Interim Action 

The FAA considers this AD to be an 

interim action. The reports that are 

required by this AD will enable the 

manufacturer to obtain better insight 

into the nature, cause, and extent of the 

unsafe condition, and eventually to 

develop final action to address the 

unsafe condition. If final action is later 

identified, the FAA might consider 

further rulemaking. 

Costs of Compliance 

The FAA estimates that this AD 

affects 79 airplanes of U.S. registry. The 

FAA estimates the following costs to 

comply with this AD: 

ESTIMATED COSTS

Action Labor cost Parts 

cost 

Cost per 

product 

Cost on U.S. 

operators 

Inspections and Tests ......... Up to 78 work-hours × $85 per hour = Up 

to $6,630 per inspection/test cycle.

$0 Up to $6,630 per inspection/test cycle.Up to $523,770 per inspection/test cycle. 

Reporting ............................. 1 work-hour × $85 per hour = $85 per inspection/test cycle.0 $85 per inspection/test 

cycle.

$6,715 per inspection/test 

cycle. 

The FAA estimates the following 

costs to do any on-condition actions that 

would be required based on the results 

of the inspections and tests. The agency 

has no way of determining the number 

of aircraft that might need these repairs/ 

replacements: 

ON-CONDITION COSTS

Action Labor cost Parts cost Cost per 

product 

Repairs/Replacements/Tests .................... Up to 120 work-hours × $85 per hour = Up to $10,200 ............ * $0 Up to $10,200. 

* The FAA has received no definitive data that would enable the FAA to provide a parts cost estimate for the on-condition repairs/replacements 

specified in this AD. 

Paperwork Reduction Act 

A federal agency may not conduct or 

sponsor, and a person is not required to 

respond to, nor shall a person be subject 

to a penalty for failure to comply with 

a collection of information subject to the 

requirements of the Paperwork 

Reduction Act unless that collection of 

information displays a currently valid 

OMB Control Number. The OMB 

Control Number for this information 

collection is 2120–0056. Public 

reporting for this collection of 

information is estimated to take 

approximately 1 hour per response, 

including the time for reviewing 

instructions, searching existing data 

sources, gathering and maintaining the 

data needed, and completing and 

reviewing the collection of information. 

All responses to this collection of 

information are mandatory. Send 

comments regarding this burden 

estimate or any other aspect of this 

collection of information, including 

suggestions for reducing this burden to: 

Information Collection Clearance 

Officer, Federal Aviation 

Administration, 10101 Hillwood 

Parkway, Fort Worth, TX 76177–1524. 

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 


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Federal Register / Vol. 89, No. 236 / Monday, December 9, 2024 / Rules and Regulations 97491 

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: 

2024–24–03 The Boeing Company: 

Amendment 39–22893; Docket No. FAA– 

2023–2403; Project Identifier AD–2023– 

00888–T. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective January 13, 2025. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to The Boeing Company 

Model MD–11 and MD–11F airplanes, 

certificated in any category, equipped with 

General Electric (GE) CF6–80C2D1F highbypass turbofan engines. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 78, Engine Exhaust. 

(e) Unsafe Condition 

This AD was prompted by a report of a 

Model MD–11F airplane experiencing an 

uncommanded deployment of a thrust 

reverser at approximately 500 feet above 

ground level. The FAA is issuing this AD to 

address uncommanded deployment of a 

thrust reverser in-flight at low altitude, 

which could result in loss of flight control of 

the airplane and loss of continued safe flight 

and landing. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

Except as specified in paragraph (h) of this 

AD: At the applicable times specified in 

paragraph 1.E., ‘‘Compliance,’’ of Boeing 

Alert Service Bulletin MD11–78A017, 

Revision 1, dated June 4, 2024, do all 

applicable actions identified as ‘‘RC’’ 

(required for compliance) in, and in 

accordance with, the Accomplishment 

Instructions of Boeing Alert Service Bulletin 

MD11–78A017, Revision 1, dated June 4, 

2024. 

(h) Exceptions to Service Bulletin 

Specifications 

(1) Where the Compliance Time columns 

of the tables in the ‘‘Compliance’’ paragraph 

of Boeing Alert Service Bulletin MD11– 

78A017, Revision 1, dated June 4, 2024, use 

the phrase ‘‘the original issue date of this 

service bulletin,’’ this AD requires using the 

effective date of this AD. 

(2) Where Step 1, Part 10 of Boeing Alert 

Service Bulletin MD11–78A017, Revision 1, 

dated June 4, 2024, specifies doing a detailed 

inspection of the junction box assembly for 

any loose electrical connection and Step 2, 

Part 11 of Boeing Alert Service Bulletin 

MD11–78A017, Revision 1, dated June 4, 

2024, specifies applying applicable torque to 

any loose electrical connection, those actions 

are not required for compliance with this AD. 

(i) Reporting 

At the applicable time specified in 

paragraph (i)(1) or (2) of this AD, submit a 

report to The Boeing Company via the Boeing 

Communication System (BCS) and include 

the information specified in Appendixes C, 

D, and E of Boeing Alert Service Bulletin 

MD11–78A017, Revision 1, dated June 4, 

2024. 

(1) If the inspection or test was done on or 

after the effective date of this AD: Submit the 

report within 90 days after the inspection or 

test. 

(2) If the inspection or test was done before 

the effective date of this AD: Submit the 

report within 90 days after the effective date 

of this AD. 

(j) Credit for Previous Actions 

This paragraph provides credit for the 

actions specified in paragraphs (g) and (i) of 

this AD, if those actions were performed 

before the effective date of this AD using 

Boeing Alert Service Bulletin MD11–78A017, 

dated December 4, 2023, except where step 

6.c.(2)(a), ‘‘CONDITON 14 OPTION 1 

(ACTION 1),’’ and step 6.c.(2)(b)4)d), 

‘‘CONDITION 14.4 OPTION 2 (ACTION 1),’’ 

of the Accomplishment Instructions of 

Boeing Service Bulletin MD11–78017, dated 

December 4, 2023, specify to replace the 

junction box, that replacement must be 

accomplished in accordance with ‘‘PART 12: 

JUNCTION BOX REPLACEMENT’’ of the 

Accomplishment Instructions of Boeing 

Service Bulletin MD11–78017, dated 

December 4, 2023. 

(k) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, AIR–520, Continued 

Operational Safety 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 AIR–520, Continued 

Operational Safety Branch, send it to the 

attention of the person identified in 

paragraph (l)(1) of this AD. Information may 

be emailed to: AMOC@faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the responsible Flight Standards Office. 

(3) An AMOC that provides an acceptable 

level of safety may be used for any repair, 

modification, or alteration required by this 

AD if it is approved by The Boeing Company 

Organization Designation Authorization 

(ODA) that has been authorized by the 

Manager, AIR–520, Continued Operational 

Safety Branch, FAA, to make those findings. 

To be approved, the repair method, 

modification deviation, or alteration 

deviation must meet the certification basis of 

the airplane, and the approval must 

specifically refer to this AD. 

(4) Except as specified by paragraph (h)(2) 

of this AD: For Boeing service bulletin that 

contains steps that are labeled as Required 

for Compliance (RC), the provisions of 

paragraphs (k)(4)(i) and (ii) of this AD apply. 

(i) The steps labeled as RC, including 

substeps under an RC step and any figures 

identified in an RC step, must be done to 

comply with the AD. If a step or substep is 

labeled ‘‘RC Exempt,’’ then the RC 

requirement is removed from that step or 

substep. An AMOC is required for any 

deviations to RC steps, including substeps 

and identified figures. 

(ii) Steps not labeled 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 RC steps, 

including substeps and identified figures, can 

still be done as specified, and the airplane 

can be put back in an airworthy condition. 

(l) Related Information 

(1) For more information about this AD, 

contact Tak Kobayashi, Aviation Safety 

Engineer, FAA, 2200 South 216th St., Des 

Moines, WA 98198; telephone 206–231– 

3553; email takahisa.kobayashi@faa.gov. 

(2) Material identified in this AD that is not 

incorporated by reference is available at the 

address 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 the AD specifies otherwise. 


ddrumheller on DSK120RN23PROD with RULES1
97492 Federal Register / Vol. 89, No. 236 / Monday, December 9, 2024 / Rules and Regulations 

(i) Boeing Alert Service Bulletin MD11– 

78A017, Revision 1, dated June 4, 2024. 

(ii) [Reserved] 

(3) For Boeing material identified in this 

AD, contact Boeing Commercial Airplanes, 

Attention: Contractual & Data Services 

(C&DS), 2600 Westminster Blvd., MC 110– 

SK57, Seal Beach, CA 90740–5600; telephone 

562–797–1717; website myboeingfleet.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 November 19, 2024. 

Peter A. White, 

Deputy Director, Integrated Certificate 

Management Division, Aircraft Certification 

Service. 

[FR Doc. 2024–28780 Filed 12–6–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–2134; Project 

Identifier MCAI–2024–00125–T; Amendment 

39–22894; AD 2024–24–04] 

RIN 2120–AA64 

Airworthiness Directives; Airbus 

Defense and Space S.A. (Formerly 

Known as Construcciones 

Aeronauticas, S.A.) Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is superseding 

Airworthiness Directive (AD) 2018–18– 

09, which applied to all Airbus Defense 

and Space S.A. Model CN–235, CN– 

235–100, CN–235–200, and CN–235– 

300 airplanes; and certain Model C–295 

airplanes. AD 2018–18–09 required a 

detailed inspection of the upper and 

lower lugs of each horizontal stabilizerto-fuselage rear attachment fitting, 

repair if necessary, and a report of 

findings. This AD was prompted by 

reports of new occurrences of cracking. 

This AD requires repetitive inspections, 

as specified in a European Union 

Aviation Safety Agency (EASA) AD, 

which is incorporated by reference. This 

AD also revises the applicability. The 

FAA is issuing this AD to address the 

unsafe condition on these products. 

DATES: This AD is effective January 13, 

2025. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of January 13, 2025. 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–2134; 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 EASA material 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 

material on the EASA website at 

ad.easa.europa.eu. 

• 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–2024–2134. 

FOR FURTHER INFORMATION CONTACT: 

Shahram Daneshmandi, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, 

Suite 410, Westbury, NY 11590; 

telephone 206–231–3220; email 

shahram.daneshmandi@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to supersede AD 2018–18–09, 

Amendment 39–19388 (83 FR 45041, 

September 5, 2018) (AD 2018–18–09). 

AD 2018–18–09 applied to all Airbus 

Defense and Space S.A. Model CN–235, 

CN–235–100, CN–235–200, and CN– 

235–300 airplanes; and certain Model 

C–295 airplanes. AD 2018–18–09 

required a detailed inspection of the 

upper and lower lugs of each horizontal 

stabilizer-to-fuselage rear attachment 

fitting, repair if necessary, and a report 

of findings. The FAA issued AD 2018– 

18–09 to address cracking, which could 

lead to reduced structural integrity of 

the lugs on the horizontal stabilizer-tofuselage rear attachment fittings. The 

unsafe condition, if not addressed, 

could result in lug or fitting failure, and 

could result in reduced controllability 

of the airplane. 

The NPRM published in the Federal 

Register on August 30, 2024 (89 FR 

70582). The NPRM was prompted by 

AD 2024–0049, dated February 20, 

2024, issued by EASA, which is the 

Technical Agent for the Member States 

of the European Union (EASA AD 2024– 

0049) (also referred to as the MCAI). The 

MCAI states that since EASA AD 2017– 

0218, dated November 8, 2017, was 

issued, new occurrences of cracking 

were reported and the manufacturer 

issued new material to provide 

instructions for repetitive highfrequency eddy current (HFEC) 

inspections for cracking of the affected 

part for all airplanes. 

In the NPRM, the FAA proposed to 

require repetitive inspections, as 

specified in EASA AD 2024–0049. The 

NPRM also proposed to revise the 

applicability. The FAA is issuing this 

AD to address cracking, which could 

lead to reduced structural integrity of 

the lugs on the horizontal stabilizer-tofuselage rear attachment fittings and 

consequent lug or fitting failure, and 

could result in reduced controllability 

of the airplane. 

You may examine the MCAI in the 

AD docket at regulations.gov under 

Docket No. FAA–2024–2134. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from a 

commenter who supported the NPRM 

without change. 

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, 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 

EASA AD 2024–0049 specifies 

procedures for repetitive HFEC 

inspections for discrepancies (including 

cracking, rework, and sharp corner 

radii) of the upper and lower lugs of 


ddrumheller on DSK120RN23PROD with RULES1