Federal Register / Vol. 86, No. 153 / Thursday, August 12, 2021 / Proposed Rules 44321 

the FAA proposes to amend 14 CFR part 

39 as follows: 

PART 39—AIRWORTHINESS 

DIRECTIVES 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive (AD): 

Airbus SAS: Docket No. FAA–2021–0657; 

Project Identifier MCAI–2021–00478–T. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by September 

27, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to Airbus SAS Model 

A350–941 and –1041 airplanes, certificated 

in any category, as identified in European 

Union Aviation Safety Agency (EASA) AD 

2021–0112, dated April 22, 2021 (EASA AD 

2021–0112). 

(d) Subject 

Air Transport Association (ATA) of 

America Code 57, Wings. 

(e) Reason 

This AD was prompted by a report 

indicating that during maintenance, a fuse 

pin retaining the main landing gear support 

structure (MLGSS) was found incorrectly 

engaged in the trunnion block and 

improperly secured with the associated 

retaining pin, due to incorrect installation 

during assembly. The FAA is issuing this AD 

to address incorrect fuse pin installations, 

which could lead to premature failure of the 

retaining pin and subsequent fuse pin 

migration and disconnection, and could 

ultimately lead to main landing gear collapse 

and possible damage to the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Requirements 

Except as specified in paragraph (h) of this 

AD: Comply with all required actions and 

compliance times specified in, and in 

accordance with, EASA AD 2021–0112. 

(h) Exceptions to EASA AD 2021–0112 

(1) Where EASA AD 2021–0112 refers to its 

effective date, this AD requires using the 

effective date of this AD. 

(2) Where paragraph (3) of EASA AD 2021– 

0112 specifies contacting Airbus for 

approved instructions for corrective actions 

for certain conditions, those corrective 

actions must be done using a method 

approved in accordance with the procedures 

specified in paragraph (j)(2) of this AD. 

(3) The ‘‘Remarks’’ section of EASA AD 

2021–0112 does not apply to this AD. 

(i) No Reporting Requirement 

Although the service information 

referenced in EASA AD 2021–0112 specifies 

to submit certain information to the 

manufacturer, this AD does not include that 

requirement. 

(j) Other FAA AD Provisions 

The following provisions also apply to this 

AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, Large Aircraft 

Section, 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 Large Aircraft 

Section, International Validation Branch, 

send it to the attention of the person 

identified in paragraph (k)(2) of this AD. 

Information may be emailed to: 9-AVS-AIR730-AMOC@faa.gov. Before using any 

approved AMOC, notify your appropriate 

principal inspector, or lacking a principal 

inspector, the manager of the responsible 

Flight Standards Office. 

(2) Contacting the Manufacturer: For any 

requirement in this AD to obtain instructions 

from a manufacturer, the instructions must 

be accomplished using a method approved 

by the Manager, Large Aircraft Section, 

International Validation Branch, FAA; or 

EASA; or Airbus SAS’s EASA Design 

Organization Approval (DOA). If approved by 

the DOA, the approval must include the 

DOA-authorized signature. 

(3) Required for Compliance (RC): If any 

service information contains procedures or 

tests that are identified as RC, those 

procedures and tests must be done to comply 

with this AD; any procedures or tests that are 

not identified as RC are recommended. Those 

procedures and tests that are not identified 

as RC may be deviated from using accepted 

methods in accordance with the operator’s 

maintenance or inspection program without 

obtaining approval of an AMOC, provided 

the procedures and tests identified as RC can 

be done and the airplane can be put back in 

an airworthy condition. Any substitutions or 

changes to procedures or tests identified as 

RC require approval of an AMOC. 

(k) Related Information 

(1) For information about EASA AD 2021– 

0112, contact EASA, Konrad-Adenauer-Ufer 

3, 50668 Cologne, Germany; telephone +49 

221 8999 000; email ADs@easa.europa.eu; 

internet www.easa.europa.eu. You may find 

this EASA AD on the EASA website at 

https://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. This 

material may be found in the AD docket on 

the internet at https://www.regulations.gov 

by searching for and locating Docket No. 

FAA–2021–0657. 

(2) For more information about this AD, 

contact Nick Wilson, Aerospace Engineer, 

Large Aircraft Section, International 

Validation Branch, FAA, 2200 South 216th 

St., Des Moines, WA 98198; telephone and 

fax 206–231–3230; email nicholas.wilson@

faa.gov. 

Issued on August 4, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–16934 Filed 8–11–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0567; Project 

Identifier AD–2021–00663–E] 

RIN 2120–AA64 

Airworthiness Directives; General 

Electric Company Turbofan Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 

certain General Electric Company (GE) 

GE90 model turbofan engines. This 

proposed AD was prompted by two 

separate in-flight shutdowns (IFSDs) 

resulting from failure of the transfer 

gearbox (TGB) radial bevel gear (TGB 

radial gearshaft). This proposed AD 

would require visual inspection of the 

TGB radial gearshaft and, depending on 

the results of the inspection, 

replacement of the TGB radial gearshaft. 

The FAA is proposing this AD to 

address the unsafe condition on these 

products. 

DATES: The FAA must receive comments 

on this proposed AD by September 27, 

2021. 

ADDRESSES: You may send comments, 

using the procedures found in 14 CFR 

11.43 and 11.45, by any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

https://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: (202) 493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue SE, 

Washington, DC 20590. 

• Hand Delivery: Deliver to Mail 

address above between 9 a.m. and 

5 p.m., Monday through Friday, except 

Federal holidays. 


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44322 Federal Register / Vol. 86, No. 153 / Thursday, August 12, 2021 / Proposed Rules 

For service information identified in 

this NPRM, contact General Electric 

Company, GE Aviation, Room 285, 1 

Neumann Way, Cincinnati, OH 45215; 

phone: (513) 552–3272; email: 

aviation.fleetsupport@ae.ge.com; 

website: www.ge.com. You may view 

this service information at the FAA, 

Airworthiness Products Section, 

Operational Safety Branch, 1200 District 

Avenue, Burlington, MA 01803. For 

information on the availability of this 

material at the FAA, call (781) 238– 

7759. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0567; or in person at Docket 

Operations between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal 

holidays. The AD docket contains this 

NPRM, any comments received, and 

other information. The street address for 

Docket Operations is listed above. 

FOR FURTHER INFORMATION CONTACT: 

Stephen Elwin, Aviation Safety 

Engineer, ECO Branch, FAA, 1200 

District Avenue, Burlington, MA 01803; 

phone: (781) 238–7236; fax: (781) 238– 

7199; email: Stephen.L.Elwin@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

The FAA invites you to send any 

written relevant data, views, or 

arguments about this proposal. Send 

your comments to an address listed 

under ADDRESSES. Include ‘‘Docket No. 

FAA–2021–0567; Project Identifier AD– 

2021–00663–E’’ at the beginning of your 

comments. The most helpful comments 

reference a specific portion of the 

proposal, explain the reason for any 

recommended change, and include 

supporting data. The FAA will consider 

all comments received by the closing 

date and may amend this proposal 

because of those comments. 

Except for Confidential Business 

Information (CBI) as described in the 

following paragraph, and other 

information as described in 14 CFR 

11.35, the FAA will post all comments 

received, without change, to https://

www.regulations.gov, including any 

personal information you provide. The 

agency will also post a report 

summarizing each substantive verbal 

contact received about this NPRM. 

Confidential Business Information 

CBI is commercial or financial 

information that is both customarily and 

actually treated as private by its owner. 

Under the Freedom of Information Act 

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

from public disclosure. If your 

comments responsive to this NPRM 

contain commercial or financial 

information that is customarily treated 

as private, that you actually treat as 

private, and that is relevant or 

responsive to this NPRM, it is important 

that you clearly designate the submitted 

comments as CBI. Please mark each 

page of your submission containing CBI 

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

marked submissions as confidential 

under the FOIA, and they will not be 

placed in the public docket of this 

NPRM. Submissions containing CBI 

should be sent to Stephen Elwin, 

Aviation Safety Engineer, ECO Branch, 

FAA, 1200 District Avenue, Burlington, 

MA 01803. Any commentary that the 

FAA receives which is not specifically 

designated as CBI will be placed in the 

public docket for this rulemaking. 

Background 

The FAA was notified of two separate 

IFSDs resulting from the failure of the 

TGB radial gearshaft. After further 

investigation, the manufacturer 

determined that rework on the TGB 

radial gearshaft teeth chamfers during 

manufacturing may have caused local 

burrs and micro-cracks which led to 

high-cycle fatigue failure. GE 

subsequently issued service information 

to provide instructions for a one-time 

visual inspection of the affected radial 

gearshafts for the presence of burrs or 

rework on TGB gearshaft teeth chamfers. 

This condition, if not addressed, could 

result in failure of one or more engines, 

loss of thrust control, and damage to the 

aircraft. 

FAA’s Determination 

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. 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed GE GE90 Service 

Bulletin (SB) 72–1201 R01, dated April 

28, 2021 (GE90 SB 72–1201 R01), and 

GE GE90–100 SB 72–0857 R01, dated 

April 28, 2021 (GE90–100 SB 72–0857 

R01). GE90 SB 72–1201 R01 specifies 

procedures for performing a one-time 

inspection of the TGB radial gearshaft 

for presence of burrs or rework on teeth 

chamfers on GE90–76B, GE90–85B, 

GE90–90B, and GE90–94B model 

turbofan engines. GE90–100 SB 72–0857 

R01 specifies procedures for performing 

a one-time inspection of the TGB radial 

gearshaft for presence of burrs or rework 

on teeth chamfers on GE90–110B1 and 

GE90–115B model turbofan engines. 

This service information is reasonably 

available because the interested parties 

have access to it through their normal 

course of business or by the means 

identified in ADDRESSES. 

Proposed AD Requirements in This 

NPRM 

This proposed AD would require 

visual inspection of the TGB radial 

gearshaft and, depending on the results 

of the inspection, replacement of the 

TGB gearshaft. 

Differences Between this Proposed 

AD and the Service Information 

GE90 SB 72–1201 R01 and GE90–100 

SB 72–0857 R01 identify affected TGB 

radial gearshafts with serial numbers (S/ 

Ns) listed in paragraph 4., APPENDIX— 

A, Table 1, and with serial numbers 

starting with prefix FIAAXXXX, 

FIA05XXX to FIA09XXX, or FIA0AXXX 

to FIA0NXXX. This AD applies only to 

TGB radial gearshafts with S/Ns listed 

in paragraph 4., APPENDIX—A, Table 1 

of GE90 SB 72–1201 R01 and GE90–100 

SB 72–0857 R01. The FAA determined 

that TGB radial gearshafts with S/Ns 

starting with prefix FIAAXXXX, 

FIA05XXX to FIA09XXX, or FIA0AXXX 

to FIA0NXXX are not required to be 

inspected and removed as part of this 

AD. However, operators may still elect 

to inspect the TGB radial gearshaft with 

these S/Ns at the next scheduled engine 

shop visit. 

Costs of Compliance 

The FAA estimates that this AD, if 

adopted as proposed, would affect 126 

engines installed on airplanes of U.S. 

registry. 

The FAA estimates the following 

costs to comply with this proposed AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Inspect TGB radial gearshaft .......................... 1 work-hour × $85 per hour = $85 ................. $0 $85 $10,710 


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Federal Register / Vol. 86, No. 153 / Thursday, August 12, 2021 / Proposed Rules 44323 

The FAA estimates the following 

costs to do any necessary replacement 

that would be required based on the 

results of the proposed inspection. The 

agency has no way of determining the 

number of aircraft that might need this 

replacement: 

ON-CONDITION COSTS

Action Labor cost Parts cost Cost per 

product 

Replace TGB radial gearshaft ...................................... 60 work-hours × $85 per hour = $5,100 ...................... $24,520 $29,620 

Authority for This Rulemaking 

Title 49 of the United States Code 

specifies the FAA’s authority to issue 

rules on aviation safety. Subtitle I, 

section 106, describes the authority of 

the FAA Administrator. Subtitle VII: 

Aviation Programs, describes in more 

detail the scope of the Agency’s 

authority. 

The FAA is issuing this rulemaking 

under the authority described in 

Subtitle VII, Part A, Subpart III, Section 

44701: General requirements. Under 

that section, Congress charges the FAA 

with promoting safe flight of civil 

aircraft in air commerce by prescribing 

regulations for practices, methods, and 

procedures the Administrator finds 

necessary for safety in air commerce. 

This regulation is within the scope of 

that authority because it addresses an 

unsafe condition that is likely to exist or 

develop on products identified in this 

rulemaking action. 

Regulatory Findings 

The FAA determined that this 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would not 

have a substantial direct effect on the 

States, on the relationship between the 

national government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government. 

For the reasons discussed above, I 

certify this proposed regulation: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Would not affect intrastate 

aviation in Alaska, and 

(3) Would not have a significant 

economic impact, positive or negative, 

on a substantial number of small entities 

under the criteria of the Regulatory 

Flexibility Act. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 14 CFR part 

39 as follows: 

PART 39—AIRWORTHINESS 

DIRECTIVES 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

General Electric Company: Docket No. FAA– 

2021–0567; Project Identifier AD–2021– 

00663–E. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by September 

27, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to General Electric 

Company (GE) GE90–76B, GE90–85B, GE90– 

90B, GE90–94B, GE90–110B1, and GE90– 

115B model turbofan engines with a transfer 

gearbox (TGB) radial bevel gear (TGB radial 

gearshaft) serial number listed in paragraph 

4., APPENDIX—A, Table 1 of GE GE90 

Service Bulletin (SB) 72–1201 R01, dated 

April 28, 2021 (GE90 SB 72–1201 R01) or 

paragraph 4., APPENDIX—A, Table 1 of GE 

GE90–100 SB 72–0857 R01, dated April 28, 

2021 (GE90–100 SB 72–0857 R01). 

(d) Subject 

Joint Aircraft System Component (JASC) 

Code 7260, Turbine Engine Accessory Drive. 

(e) Unsafe Condition 

This AD was prompted by two separate inflight shutdowns resulting from the failure of 

the TGB radial gearshaft. The FAA is issuing 

this AD to prevent failure of the TGB radial 

gearshaft. The unsafe condition, if not 

addressed, could result in failure of one or 

more engines, loss of thrust control, and 

damage to the aircraft. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

(1) At the next engine shop visit after the 

effective date of this AD, perform a visual 

inspection of the affected TGB radial 

gearshaft using the Accomplishment 

Instructions, paragraph 3.A.(3)(a)1 through 3, 

of GE90 SB 72–1201 R01 or GE90–100 SB 

72–0857 R01, as applicable. 

(2) If, during the visual inspection required 

by paragraph (g)(1) of this AD, discrepancies 

are found that meet the criteria in the 

Accomplishment Instructions, paragraph 

3.A.(4)(a) or 3.A.(4)(b), of GE90 SB 72–1201 

R01 or GE90–100 SB 72–0857 R01, before 

further flight, replace the TGB radial 

gearshaft with a part eligible for installation. 

(h) Definitions 

(1) For the purpose of this AD, an ‘‘engine 

shop visit’’ is when the compressor discharge 

pressure seal joint is disassembled. 

(2) For the purpose of this AD, a ‘‘part 

eligible for installation’’ is a TGB radial 

gearshaft that does not have raised material 

or rework on the teeth chamfers as described 

in the Accomplishment Instructions, 

paragraph 3.A.(4)(a) or 3.A.(4)(b), of GE90 SB 

72–1201 R01 or GE90–100 SB 72–0857 R01. 

(i) Credit for Previous Actions 

You may take credit for the inspection of 

the affected TGB radial gearshaft required by 

paragraph (g)(1) of this AD if you performed 

the inspection before the effective date of this 

AD using GE GE90 SB 72–1201 R00, dated 

January 5, 2021, or GE GE90–100 SB 72–0857 

R00, dated January 5, 2021. 

(j) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, ECO Branch, FAA, has 

the authority to approve AMOCs for this AD, 

if requested using the procedures found in 14 

CFR 39.19. In accordance with 14 CFR 39.19, 

send your request to your principal inspector 

or local Flight Standards District Office, as 

appropriate. If sending information directly 

to the manager of the certification office, 

send it to the attention of the person 

identified in Related Information. You may 

email your request to ANE-AD-AMOC@

faa.gov. 

(2) Before using any approved AMOC, 

notify your appropriate principal inspector, 

or lacking a principal inspector, the manager 

of the local flight standards district office/ 

certificate holding district office. 

(k) Related Information 

(1) For more information about this AD, 

contact Stephen Elwin, Aviation Safety 

Engineer, ECO Branch, FAA, 1200 District 

Avenue, Burlington, MA 01803; phone: (781) 

238–7236; fax: (781) 238–7199; email: 

Stephen.L.Elwin@faa.gov. 

(2) For service information identified in 

this AD, contact General Electric Company, 

GE Aviation, Room 285, 1 Neumann Way, 


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44324 Federal Register / Vol. 86, No. 153 / Thursday, August 12, 2021 / Proposed Rules 

Cincinnati, OH 45215; phone: (513) 552– 

3272; email: aviation.fleetsupport@

ae.ge.com; website: www.ge.com. You may 

view this referenced service information at 

the FAA, Airworthiness Products Section, 

Operational Safety Branch, 1200 District 

Avenue, Burlington, MA 01803. For 

information on the availability of this 

material at the FAA, call (781) 238–7759. 

Issued on July 9, 2021. 

Gaetano A. Sciortino, 

Deputy Director for Strategic Initiatives, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–16758 Filed 8–11–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0656; Project 

Identifier MCAI–2021–00394–T] 

RIN 2120–AA64 

Airworthiness Directives; De Havilland 

Aircraft of Canada Limited (Type 

Certificate Previously Held by 

Bombardier, Inc.) Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 

certain De Havilland Aircraft of Canada 

Limited Model DHC–8–401 and –402 

airplanes. This proposed AD was 

prompted by reports of loss of hydraulic 

fluid and annunciation of the check fire 

detect light. This proposed AD would 

require doing a detailed visual 

inspection for chafing and proper 

clearance of the left-hand (LH) and 

right-hand (RH) main landing gear 

(MLG) primary zone advanced 

pneumatic detector (APD) sensing lines, 

the hydraulic tube assemblies, and the 

surrounding structure, and doing all 

applicable corrective actions. The FAA 

is proposing this AD to address the 

unsafe condition on these products. 

DATES: The FAA must receive comments 

on this proposed AD by September 27, 

2021. 

ADDRESSES: You may send comments, 

using the procedures found in 14 CFR 

11.43 and 11.45, by any of the following 

methods: 

• Federal eRulemaking Portal: Go to 

https://www.regulations.gov. Follow the 

instructions for submitting comments. 

• Fax: 202–493–2251. 

• Mail: U.S. Department of 

Transportation, Docket Operations, M– 

30, West Building Ground Floor, Room 

W12–140, 1200 New Jersey Avenue SE, 

Washington, DC 20590. 

• Hand Delivery: Deliver to Mail 

address above between 9 a.m. and 5 

p.m., Monday through Friday, except 

Federal holidays. 

For service information identified in 

this NPRM, contact De Havilland 

Aircraft of Canada Limited, Q-Series 

Technical Help Desk, 123 Garratt 

Boulevard, Toronto, Ontario M3K 1Y5, 

Canada; telephone 416–375–4000; fax 

416–375–4539; email thd@

dehavilland.com; internet https://

dehavilland.com. You may view this 

service information 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. 

Examining the AD Docket 

You may examine the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0656; or in person at Docket 

Operations between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal 

holidays. The AD docket contains this 

NPRM, any comments received, and 

other information. The street address for 

Docket Operations is listed above. 

FOR FURTHER INFORMATION CONTACT: 

Chirayu Gupta, Aerospace Engineer, 

Mechanical Systems and Administrative 

Services Section, FAA, New York ACO 

Branch, 1600 Stewart Avenue, Suite 

410, Westbury, NY 11590; telephone 

516–228–7300; fax 516–794–5531; email 

9-avs-nyaco-cos@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

The FAA invites you to send any 

written relevant data, views, or 

arguments about this proposal. Send 

your comments to an address listed 

under ADDRESSES. Include ‘‘Docket No. 

FAA–2021–0656; Project Identifier 

MCAI–2021–00394–T’’ at the beginning 

of your comments. The most helpful 

comments reference a specific portion of 

the proposal, explain the reason for any 

recommended change, and include 

supporting data. The FAA will consider 

all comments received by the closing 

date and may amend the proposal 

because of those comments. 

Except for Confidential Business 

Information (CBI) as described in the 

following paragraph, and other 

information as described in 14 CFR 

11.35, the FAA will post all comments 

received, without change, to https://

www.regulations.gov, including any 

personal information you provide. The 

agency will also post a report 

summarizing each substantive verbal 

contact received about this NPRM. 

Confidential Business Information 

CBI is commercial or financial 

information that is both customarily and 

actually treated as private by its owner. 

Under the Freedom of Information Act 

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

from public disclosure. If your 

comments responsive to this NPRM 

contain commercial or financial 

information that is customarily treated 

as private, that you actually treat as 

private, and that is relevant or 

responsive to this NPRM, it is important 

that you clearly designate the submitted 

comments as CBI. Please mark each 

page of your submission containing CBI 

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

marked submissions as confidential 

under the FOIA, and they will not be 

placed in the public docket of this 

NPRM. Submissions containing CBI 

should be sent to Chirayu Gupta, 

Aerospace Engineer, Mechanical 

Systems and Administrative Services 

Section, FAA, New York ACO Branch, 

1600 Stewart Avenue, Suite 410, 

Westbury, NY 11590; telephone 516– 

228–7300; fax 516–794–5531; email 9- 

avs-nyaco-cos@faa.gov. Any 

commentary that the FAA receives 

which is not specifically designated as 

CBI will be placed in the public docket 

for this rulemaking. 

Background 

Transport Canada Civil Aviation 

(TCCA), which is the aviation authority 

for Canada, has issued TCCA AD CF– 

2021–12, dated April 14, 2021 (also 

referred to after this as the Mandatory 

Continuing Airworthiness Information, 

or the MCAI), to correct an unsafe 

condition for certain De Havilland 

Aircraft of Canada Limited Model DHC– 

8–401 and –402 airplanes. You may 

examine the MCAI in the AD docket at 

https://www.regulations.gov by 

searching for and locating Docket No. 

FAA–2021–0656. 

This proposed AD was prompted by 

reports of loss of hydraulic fluid and 

annunciation of the check fire detect 

light. The FAA is proposing this AD to 

address insufficient separation between 

the APD sensing line and surrounding 

components, which could lead to a 

hydraulic leak, loss of hydraulic 

systems, and loss of fire detection in the 

MLG primary zone should prolonged 

contact occur. See the MCAI for 

additional background information. 


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