Federal Register / Vol. 86, No. 142 / Wednesday, July 28, 2021 / Proposed Rules 40373 

pilot and co-pilot yaw pedal assemblies. The 

FAA is issuing this AD to address failure of 

a yaw pedal adjuster, which could result in 

reduced yaw control of the helicopter. 

(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 2019–0252. 

(h) Exceptions to EASA AD 2019–0252 

(1) Where EASA AD 2019–0252 refers to 

flight hours (FH), this AD requires using 

hours time-in-service. 

(2) Where EASA AD 2019–0252 refers to its 

effective date, this AD requires using the 

effective date of this AD. 

(3) Where the service information 

referenced in EASA AD 2019–0252 specifies 

to discard certain parts, this AD requires 

removing those parts from service. 

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

2019–0252 does not apply to this AD. 

(i) No Reporting Requirement 

Although the service information 

referenced in EASA AD 2019–0252 specifies 

to submit certain information to the 

manufacturer, this AD does not include that 

requirement. 

(j) Special Flight Permit 

Special flight permits, as described in 14 

CFR 21.197 and 21.199, are prohibited. 

(k) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, International Validation 

Branch, FAA, has the authority to approve 

AMOCs for this AD, if requested using the 

procedures found in 14 CFR 39.19. In 

accordance with 14 CFR 39.19, send your 

request to your principal inspector or local 

Flight Standards District Office, as 

appropriate. If sending information directly 

to the manager of the International Validation 

Branch, send it to the attention of the person 

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

Information may be emailed to: 9-AVS-AIR730-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. 

(l) Related Information 

(1) For EASA AD 2019–0252, 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 view this 

material at the FAA, Office of the Regional 

Counsel, Southwest Region, 10101 Hillwood 

Pkwy., Room 6N–321, Fort Worth, TX 76177. 

For information on the availability of this 

material at the FAA, call (817) 222–5110. 

This material may be found in the AD docket 

at https://www.regulations.gov by searching 

for and locating Docket No. FAA–2021–0570. 

(2) For more information about this AD, 

contact Jacob Fitch, Aerospace Engineer, COS 

Program Management Section, Operational 

Safety Branch, Compliance & Airworthiness 

Division, FAA, 10101 Hillwood Pkwy., Fort 

Worth, TX 76177; telephone (817) 222–4130; 

email jacob.fitch@faa.gov. 

Issued on July 11, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–15950 Filed 7–27–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0568; Project 

Identifier MCAI–2021–00446–T] 

RIN 2120–AA64 

Airworthiness Directives; Airbus SAS 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for all 

Airbus SAS Model A330–200, –200 

Freighter, –300 and –900 series 

airplanes; and Model A340–200, –300, 

–500, and –600 series airplanes. This 

proposed AD was prompted by a report 

that during the frame of flight test 

clearance process, a detailed analysis of 

air data reference (ADR) failure 

scenarios led to the identification that 

compliance requirements for loads and 

handling qualities throughout the flight 

envelope could be impaired in case of 

dispatch with one ADR inoperative 

(master minimum equipment list 

(MMEL) item 34–10–01) during the 

maximum interval allowed by the 

current MMEL. This proposed AD 

would require revising the operator’s 

existing FAA-approved minimum 

equipment list (MEL) for the air data/ 

inertial reference system, as specified in 

a European Union Aviation Safety 

Agency (EASA) AD, which is proposed 

for incorporation by reference. 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 13, 

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 material that will be incorporated 

by reference (IBR) in this AD, 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 IBR material on the EASA 

website at https://ad.easa.europa.eu. 

You may view this IBR 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 in the AD docket on 

the internet at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2021– 

0568. 

Examining the AD Docket 

You may examine the AD docket on 

the internet at https://

www.regulations.gov by searching for 

and locating Docket No. FAA–2021– 

0568; 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: 

Vladimir Ulyanov, Aerospace Engineer, 

Large Aircraft Section, International 

Validation Branch, FAA, 2200 South 

216th St., Des Moines, WA 98198; 

telephone and fax: 206–231–3229; email 

vladimir.ulyanov@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–2021–0568; Project Identifier 

MCAI–2021–00446–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 


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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 proposed 

AD. 

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 Vladimir Ulyanov, 

Aerospace Engineer, Large Aircraft 

Section, International Validation 

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

Moines, WA 98198; telephone and fax: 

206–231–3229; email vladimir.ulyanov@

faa.gov. Any commentary that the FAA 

receives which is not specifically 

designated as CBI will be placed in the 

public docket for this rulemaking. 

Background 

EASA, which is the Technical Agent 

for the Member States of the European 

Union, has issued EASA AD 2021–0103, 

dated April 13, 2021 (EASA AD 2021– 

0103) (also referred to as the Mandatory 

Continuing Airworthiness Information, 

or the MCAI), to correct an unsafe 

condition for all Airbus SAS Model 

A330–200, –200 Freighter, –300 and 

–900 series airplanes; Model A340–200 

and –300 series airplanes; and Model 

A340–541, –542, –642, and –643 

airplanes. Model A340–542 and –643 

airplanes are not certificated by the FAA 

and are not included on the U.S. type 

certificate data sheet; this AD therefore 

does not include those airplanes in the 

applicability. 

This proposed AD was prompted by 

a report that during the frame of flight 

test clearance process, a detailed 

analysis of ADR failure scenarios led to 

the identification that compliance 

requirements for loads and handling 

qualities throughout the flight envelope 

could be impaired in case of dispatch 

with one ADR inoperative (MMEL item 

34–10–01) during the maximum interval 

allowed by the current MMEL. The FAA 

is proposing this AD to address the 

possibility of in-flight loss of a second 

ADR combined with erroneous low 

speed data provided by the remaining 

functional ADR, which could result in 

loss of control of the airplane. See the 

MCAI for additional background 

information. 

Related Service Information Under 1 

CFR Part 51 

EASA AD 2021–0103 describes 

procedures for revising the air data/ 

inertial reference system for MMEL item 

34–10–01. This material is reasonably 

available because the interested parties 

have access to it through their normal 

course of business or by the means 

identified in the ADDRESSES section. 

FAA’s Determination and Requirements 

of This Proposed AD 

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 the State 

of Design Authority, the FAA has been 

notified of the unsafe condition 

described in the MCAI referenced 

above. The FAA is proposing this AD 

because the FAA evaluated all the 

relevant information and determined 

the unsafe condition described 

previously is likely to exist or develop 

in other products of the same type 

design. 

Proposed AD Requirements 

This proposed AD would require 

accomplishing the actions specified in 

EASA AD 2021–0103 described 

previously, as incorporated by 

reference, except for any differences 

identified as exceptions in the 

regulatory text of this AD. 

EASA AD 2021–0103 requires 

operators to ‘‘inform all flight crews’’ of 

revisions to the MMEL, and thereafter to 

‘‘operate the aeroplane accordingly.’’ 

However, this proposed AD would not 

specifically require those actions as they 

are already required by FAA 

regulations. 

FAA regulations (14 CFR 

121.628(a)(2)) require operators to 

provide pilots with access to all of the 

information contained in the operator’s 

MEL. 

Furthermore, 14 CFR 121.628(a)(5) 

requires airplanes to be operated under 

all applicable conditions and limitations 

contained in the operator’s MEL. 

Therefore, including a requirement in 

this AD to operate the airplane 

according to the revised MEL would be 

redundant and unnecessary. Further, 

compliance with such a requirement in 

an AD would be impracticable to 

demonstrate or track on an ongoing 

basis; therefore, a requirement to 

operate the airplane in such a manner 

would be unenforceable. 

Explanation of Required Compliance 

Information 

In the FAA’s ongoing efforts to 

improve the efficiency of the AD 

process, the FAA developed a process to 

use certain civil aviation authority 

(CAA) ADs as the primary source of 

information for compliance with 

requirements for corresponding FAA 

ADs. The FAA has been coordinating 

this process with manufacturers and 

CAAs. As a result, EASA AD 2021–0103 

will be incorporated by reference in the 

FAA final rule. This proposed AD 

would, therefore, require compliance 

with EASA AD 2021–0103 in its 

entirety, through that incorporation, 

except for any differences identified as 

exceptions in the regulatory text of this 

proposed AD. Using common terms that 

are the same as the heading of a 

particular section in EASA AD 2021– 

0103 does not mean that operators need 

comply only with that section. For 

example, where the AD requirement 

refers to ‘‘all required actions and 

compliance times,’’ compliance with 

this AD requirement is not limited to 

the section titled ‘‘Required Action(s) 

and Compliance Time(s)’’ in EASA AD 

2021–0103. Service information 

specified in EASA AD 2021–0103 that is 

required for compliance with it will be 

available at https://www.regulations.gov 

by searching for and locating Docket No. 

FAA–2021–0568 after the FAA final 

rule is published. 

Costs of Compliance 

The FAA estimates that this proposed 

AD affects 130 airplanes of U.S. registry. 

The FAA estimates the following costs 

to comply with this proposed AD: 


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ESTIMATED COSTS FOR REQUIRED ACTIONS

Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

2 work-hours × $85 per hour = $170 .......................................................................................... $0 $170 $22,100 

Authority for This Rulemaking 

Title 49 of the United States Code 

specifies the FAA’s authority to issue 

rules on aviation safety. Subtitle I, 

section 106, describes the authority of 

the FAA Administrator. Subtitle VII: 

Aviation Programs, describes in more 

detail the scope of the Agency’s 

authority. 

The FAA is issuing this rulemaking 

under the authority described in 

Subtitle VII, Part A, Subpart III, Section 

44701: General requirements. Under 

that section, Congress charges the FAA 

with promoting safe flight of civil 

aircraft in air commerce by prescribing 

regulations for practices, methods, and 

procedures the Administrator finds 

necessary for safety in air commerce. 

This regulation is within the scope of 

that authority because it addresses an 

unsafe condition that is likely to exist or 

develop on products identified in this 

rulemaking action. 

Regulatory Findings 

The FAA determined that this 

proposed AD would not have federalism 

implications under Executive Order 

13132. This proposed AD would not 

have a substantial direct effect on the 

States, on the relationship between the 

national Government and the States, or 

on the distribution of power and 

responsibilities among the various 

levels of government. 

For the reasons discussed above, I 

certify this proposed regulation: 

(1) Is not a ‘‘significant regulatory 

action’’ under Executive Order 12866, 

(2) Would not affect intrastate 

aviation in Alaska, and 

(3) Would not have a significant 

economic impact, positive or negative, 

on a substantial number of small entities 

under the criteria of the Regulatory 

Flexibility Act. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, Incorporation by reference, 

Safety. 

The Proposed Amendment 

Accordingly, under the authority 

delegated to me by the Administrator, 

the FAA proposes to amend 14 CFR part 

39 as follows: 

PART 39—AIRWORTHINESS 

DIRECTIVES 

■ 1. The authority citation for part 39 

continues to read as follows: 

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

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

Airbus SAS: Docket No. FAA–2021–0568; 

Project Identifier MCAI–2021–00446–T. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by September 

13, 2021. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all Airbus SAS 

airplanes specified in paragraphs (c)(1) 

through (8) of this AD, certificated in any 

category. 

(1) Model A330–201, –202, –203, –223, and 

–243 airplanes. 

(2) Model A330–223F and –243F airplanes. 

(3) Model A330–301, –302, –303, –321, 

–322, –323, –341, –342, and –343 airplanes. 

(4) Model A330–941 airplanes. 

(5) Model A340–211, –212, and –213 

airplanes. 

(6) Model A340–311, –312, and –313 

airplanes. 

(7) Model A340–541 airplanes. 

(8) Model A340–642 airplanes. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 34, Navigation. 

(e) Reason 

This AD was prompted by a report that 

during the frame of flight test clearance 

process, a detailed analysis of air data 

reference (ADR) failure scenarios led to the 

identification that compliance requirements 

for loads and handling qualities throughout 

the flight envelope could be impaired in case 

of dispatch with one ADR inoperative 

(master minimum equipment list (MMEL) 

item 34–10–01) during the maximum interval 

allowed by the current MMEL. The FAA is 

issuing this AD to address the possibility of 

in-flight loss of a second ADR combined with 

erroneous low speed data provided by the 

remaining functional ADR, which could 

result in loss of control of the airplane. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Requirements 

Except as specified in paragraph (h) of this 

AD: Comply with all required actions and 

compliance times specified in, and in 

accordance with, European Union Aviation 

Safety Agency (EASA) AD 2021–0103, dated 

April 13, 2021 (EASA AD 2021–0103). 

(h) Exceptions to EASA AD 2021–0103 

(1) Where EASA AD 2021–0103 refers to its 

effective date, this AD requires using the 

effective date of this AD. 

(2) Where EASA AD 2021–0103 specifies 

to implement certain information in ‘‘the 

MMEL MER’’ into the ‘‘operational 

documentation,’’ this AD requires revising 

the operator’s existing FAA-approved 

minimum equipment list (MEL) to 

incorporate that information. 

(3) Where EASA AD 2021–0103 specifies 

to ‘‘inform all flight crews, and, thereafter, 

operate the aeroplane accordingly,’’ this AD 

does not require those actions as those 

actions are already required by existing FAA 

operating regulations. 

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

2021–0103 does not apply to this AD. 

(i) 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 (j)(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): Except 

as required by paragraph (i)(2) of this AD, 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 


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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. 

(j) Related Information 

(1) For information about EASA AD 2021– 

0103 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–2021–0568. 

(2) For more information about this AD, 

contact Vladimir Ulyanov, Aerospace 

Engineer, Large Aircraft Section, 

International Validation Branch, FAA, 2200 

South 216th St., Des Moines, WA 98198; 

telephone and fax: 206 231 3229; email 

vladimir.ulyanov@faa.gov. 

Issued on July 21, 2021. 

Gaetano A. Sciortino, 

Deputy Director for Strategic Initiatives, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2021–15942 Filed 7–27–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0032; Project 

Identifier AD–2020–01314–P] 

RIN 2120–AA64 

Airworthiness Directives; Hamilton 

Sundstrand Corporation Propellers; 

Initial Regulatory Flexibility Analysis 

AGENCY: Federal Aviation 

Administration (FAA), Transportation 

(DOT). 

ACTION: Initial regulatory flexibility 

analysis (IRFA); request for comment. 

SUMMARY: The FAA is publishing and 

requesting comments on this IRFA for 

the previously published notice of 

proposed rulemaking (NPRM), Project 

Identifier AD–2020–01314–P, applicable 

to Hamilton Sundstrand Corporation 

54H model propellers with a 54H60 

model propeller hub installed. That 

NPRM proposed to supersede 

Airworthiness Directive (AD) 2020–12– 

07, which applies to certain Hamilton 

Sundstrand Corporation (Hamilton 

Sundstrand) 54H model propellers. 

DATES: Comments on this IRFA for the 

NPRM published on February 25, 2021 

(86 FR 11473), must be received on or 

before September 13, 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 

http://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 FURTHER INFORMATION CONTACT: 

Michael Schwetz, Aviation Safety 

Engineer, Boston ACO Branch, FAA, 

1200 District Avenue, Burlington, MA 

01803; phone: (781) 238–7761; fax: (781) 

238–7199; email: michael.schwetz@

faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

The FAA invites you to send any 

written relevant data, views, or 

arguments about this IRFA. Send your 

comments to an address listed under 

ADDRESSES. Include ‘‘Docket No. FAA– 

2021–0032; Project Identifier AD–2020– 

01314–P’’ 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 we receive about this proposed 

AD. 

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 Michael Schwetz, 

Aviation Safety Engineer, Boston ACO 

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 issued AD 2020–12–07, 

Amendment 39–21142 (85 FR 36145, 

June 15, 2020) (AD 2020–12–07) for 

certain Hamilton Sundstrand 54H 

model propellers. AD 2020–12–07 was 

prompted by a report of the separation 

of a 54H60 model propeller blade 

installed on a United States Marine 

Corps Reserve (USMCR) KC–130T 

airplane during a flight in July 2017. 

The USMCR investigation of this event 

revealed the Hamilton Sundstrand 

54H60 model propeller blade separated 

due to corrosion pitting and a resultant 

intergranular radial crack that was not 

corrected at the last propeller overhaul. 

From this intergranular crack, a fatigue 

crack initiated and grew under service 

loading until the Hamilton Sundstrand 

54H60 model propeller blade could no 

longer sustain the applied loads and 

ultimately the blade separated. The 

separation of the blade resulted in the 

loss of the airplane and 17 fatalities. The 

investigation further revealed that 

54H60 model propeller blades 

manufactured before 1971 are 

susceptible to cracks of the propeller 

blade in the area of the internal taper 

bore. The applicability of AD 2020–12– 

07 was therefore limited to those 

Hamilton Sundstrand 54H60 model 

propellers blades with a blade serial 

number (S/N) below 813320, which are 

those propeller blades manufactured 

before 1971. AD 2020–12–07 required 

initial and repetitive eddy current 

inspections (ECIs) of the affected 

propeller blades and replacement of any 

propeller blade that fails inspection. 

The agency issued AD 2020–12–07 to 

detect cracking in the propeller blade 

taper bore. 


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