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Proposed Rules
Federal Register Vol. 86, No. 36
Thursday, February 25, 2021

This section of the FEDERAL REGISTER
contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules.

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration 14 CFR Part 39
Docket No. FAA20210032; Project Identifier AD202001314P
RIN 2120AA64

Airworthiness Directives; Hamilton Sundstrand Corporation Propellers Federal Aviation Administration FAA, DOT.
ACTION: Notice of proposed rulemaking NPRM.
AGENCY:

The FAA proposes to supersede Airworthiness Directive AD
20201207, which applies to certain Hamilton Sundstrand Corporation Hamilton Sundstrand 54H model propellers. AD 20201207 requires initial and repetitive eddy current inspections ECI of certain propeller blades and replacement of the propeller blades that fail the inspection. Since the FAA issued AD 20201207, the manufacturer determined that all propeller blades installed on Hamilton Sundstrand 54H model propellers with a 54H60 model propeller hub are susceptible to intergranular corrosion cracking in the blade taper bore. This proposed AD would require initial and repetitive ECI of all propeller blades installed on Hamilton Sundstrand 54H60 propeller hubs and replacement of any propeller blade that fails inspection. 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 April 12, 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 4932251.
Mail: U.S. Department of Transportation, Docket Operations, M
SUMMARY:

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30, West Building Ground Floor, Room W12140, 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 Hamilton Sundstrand, 1 Hamilton Road, Windsor Locks, CT 060961010; phone: 877
8087575; email: CRC@collins.com. You may view this service information at 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.
FAA20210032; 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:
Michael Schwetz, Aviation Safety Engineer, Boston ACO Branch, FAA, 1200 District Avenue, Burlington, MA
01803; phone: 781 2387761; fax: 781
2387199; email: michael.schwetz@
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.
FAA20210032; Project Identifier AD
202001314P 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

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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 20201207, Amendment 3921142 85 FR 36145, June 15, 2020 AD 20201207 for certain Hamilton Sundstrand 54H
model propellers. Note that AD 2020
1207 and the Hamilton Sundstrand service information reference 54H60
model propellers whereas this AD
references 54H model propellers.
Hamilton Sundstrand 54H60 model propellers are 54H model propellers with a 54H60 model propeller hub.
AD 20201207 was prompted by a report of the separation of a 54H60
model propeller blade installed on a United States Marine Corps Reserve USMCR KC130T 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
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