35416 Federal Register / Vol. 86, No. 126 / Tuesday, July 6, 2021 / Proposed Rules 

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–2021–0545. 

(2) For more information about this AD, 

contact Kathleen Arrigotti, Aerospace 

Engineer, Large Aircraft Section, 

International Validation Branch, FAA, 2200 

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

telephone and fax 206–231–3218; email 

kathleen.arrigotti@faa.gov. 

Issued on June 29, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–14269 Filed 7–2–21; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2021–0546; Project 

Identifier MCAI–2021–00387–P] 

RIN 2120–AA64 

Airworthiness Directives; Hoffmann 

GmbH & Co. KG Propellers 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to 

supersede Airworthiness Directive (AD) 

2020–25–05, which applies to all 

Hoffmann GmbH & Co. KG (Hoffmann) 

model HO–V 72 propellers. AD 2020– 

25–05 requires amending the existing 

aircraft flight manual (AFM) with 

abnormal propeller vibration 

instructions. AD 2020–25–05 also 

requires visual inspection and nondestructive test (NDT) inspection of the 

propeller hub and, depending on the 

results of the inspections, replacement 

of the propeller hub with a part eligible 

for installation. AD 2020–25–05 also 

requires replacement of the propeller 

hub before exceeding 30 years since the 

date of manufacture. Since the FAA 

issued AD 2020–25–05, analyses of the 

inspection results showed that the 30- 

year life limit of the propeller hub is no 

longer needed. This proposed AD would 

retain certain requirements of AD 2020– 

25–05 and remove the 30-year life limit 

of the propeller hub. 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 August 20, 

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 Hoffmann GmbH & 

Co. KG, Ku ̈pferlingstrasse 9, 83022, 

Rosenheim, Germany; phone: +49 0 

8031 1878 0; email: info@hoffmannprop.com; website: https://hoffmannprop.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–2021–0546; 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, the mandatory continuing 

airworthiness information (MCAI), 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) 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 proposal. Send 

your comments to an address listed 

under ADDRESSES. Include ‘‘Docket No. 

FAA–2021–0546; Project Identifier 

MCAI–2021–00387–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 2020–25–05, 

Amendment 39–21347 (85 FR 78702, 

December 7, 2020), (AD 2020–25–05), 

for all Hoffmann model HO–V 72 

propellers. AD 2020–25–05 was 

prompted by reports of cracks at 

different positions on two affected 

propeller hubs. AD 2020–25–05 requires 

amending the existing AFM with 

abnormal propeller vibration 

instructions. AD 2020–25–05 also 

requires visual inspection and NDT 

inspection of the propeller hub and, 

depending on the results of the 

inspections, replacement of the 

propeller hub with a part eligible for 

installation. AD 2020–25–05 also 

requires replacement of the propeller 

hub before exceeding 30 years since the 

date of manufacture or within 30 days 

after the effective date of AD 2020–25– 

05, whichever occurs later. The agency 

issued AD 2020–25–05 to prevent 

failure of the propeller hub. 


jbell on DSKJLSW7X2PROD with PROPOSALS
Federal Register / Vol. 86, No. 126 / Tuesday, July 6, 2021 / Proposed Rules 35417 

Actions Since AD 2020–25–05 Was 

Issued 

Since the FAA issued AD 2020–25– 

05, the European Union Aviation Safety 

Agency (EASA), which is the Technical 

Agent for the Member States of the 

European Community, has issued EASA 

AD 2020–0226R1, dated March 31, 2021 

(referred to after this as ‘‘the MCAI’’), to 

address the unsafe condition on these 

products. The MCAI states: 

Cracks have been reported at different 

positions on two affected parts, both installed 

on Slingsby T67 ‘‘Firefly’’ aeroplanes. One 

crack was found during scheduled 

inspection, the other crack during an 

unscheduled inspection after abnormal 

vibrations occurred. Both cases are under 

investigation by Hoffmann Propeller. 

This condition, if not detected and 

corrected, could lead to in-flight propeller 

detachment, possibly resulting in damage to 

the airplane and/or injury to persons on the 

ground. 

To address this potential unsafe condition, 

Hoffmann issued the SB, providing 

applicable instructions. 

For the reasons described above, EASA 

issued Emergency AD 2020–0226–E to 

require inspections of affected parts and, 

depending on findings, replacement, and 

introduces a life limit for affected parts. That 

[EASA] AD also required, for certain 

aeroplanes, amendment of the applicable 

Aircraft Flight Manual (AFM). 

Since that [EASA] AD was issued, recent 

analyses of inspection results showed that 

the life limit of 30 years is no longer 

necessary and Hoffmann Propeller issued 

Revision D of the SB accordingly. 

This [EASA] AD is revised to delete the life 

limit and to introduce a clarification for 

corrective action(s) during overhaul in 

paragraph (6) [of EASA AD]. 

You may obtain further information 

by examining the MCAI in the AD 

docket at https://www.regulations.gov 

by searching for and locating Docket No. 

FAA–2021–0546. 

In addition, Hoffmann issued Service 

Bulletin SB E53, Rev. D, dated February 

18, 2021, to no longer specify that the 

propeller hub be replaced before 

exceeding 30 years since the date of 

manufacture. 

FAA’s Determination 

This product has been approved by 

EASA and is approved for operation in 

the United States. Pursuant to the FAA’s 

bilateral agreement with the European 

Community, EASA has notified the FAA 

of the unsafe condition described in the 

MCAI and service information. The 

FAA is issuing this NPRM because the 

agency evaluated all the relevant 

information provided by EASA and 

determined the unsafe condition 

described previously is likely to exist or 

develop in other products of the same 

type design. 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed Hoffmann 

Propeller GmbH & Co. KG Service 

Bulletin SB E53, Rev. D, dated February 

18, 2021. This service information 

specifies procedures for visual and NDT 

inspections of the propeller hub for 

cracks. 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 retain 

certain requirements of AD 2020–25–05. 

This proposed AD would no longer 

require that the propeller hub be 

replaced before exceeding 30 years since 

the date of manufacture or within 30 

days after the effective date of AD 2020– 

25–05. 

Differences Between the Proposed AD 

and MCAI or Service Information 

EASA AD 2020–0226R1, dated March 

31, 2021, applies to Hoffmann HO–V 72 

propellers with propeller hub HO–V 72 

( ) ( )–( )–( ) that have been used or are 

expected to be used for aerobatic 

maneuvers. This proposed AD applies 

to all Hoffmann model HO–V 72 

propellers regardless of their use. 

Hoffmann Propeller GmbH & Co. KG 

Service Bulletin SB E53, Rev. D, dated 

February 18, 2021, specifies that 

operators must send any propeller 

found with a crack to Hoffmann for 

investigation. The service bulletin also 

specifies that operators must report any 

propeller with cracked hubs to 

Hoffmann. This proposed AD does not 

mandate sending the propeller or 

information to Hoffmann. 

Costs of Compliance 

The FAA estimates that this AD, if 

adopted as proposed, would affect 35 

propellers 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 

Amend AFM .................................................... 1 work-hour × $85 per hour = $85 ................. $0 $85 $2,975 

Visually inspect propeller hub ......................... 1 work-hour × $85 per hour = $85 ................. 0 85 2,975 

NDT inspect propeller hub .............................. 8 work-hours × $85 per hour = $680 ............. 0 680 23,800 

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 propeller hub .................................................. 5 work-hours × $85 per hour = $425 ........................... $1,600 $2,025 

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 


jbell on DSKJLSW7X2PROD with PROPOSALS
35418 Federal Register / Vol. 86, No. 126 / Tuesday, July 6, 2021 / Proposed Rules 

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 has 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 that the 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: 

■ a. Removing Airworthiness Directive 

AD 2020–25–05, Amendment 39–21347 

(85 FR 78702, December 7, 2020); and 

■ b. Adding the following new 

airworthiness directive: 

Hoffmann GmbH & Co. KG: Docket No. 

FAA–2021–0546; Project Identifier 

MCAI–2021–00387–P. 

(a) Comments Due Date 

The FAA must receive comments on this 

airworthiness directive (AD) by August 20, 

2021. 

(b) Affected ADs 

This AD replaces AD 2020–25–05, 

Amendment 39–21347 (85 FR 78702, 

December 7, 2020). 

(c) Applicability 

This AD applies to all Hoffmann GmbH & 

Co. KG HO–V 72 propellers. 

(d) Subject 

Joint Aircraft System Component (JASC) 

Code 6114, Propeller Hub Section. 

(e) Unsafe Condition 

This AD was prompted by reports of cracks 

at different positions on two affected 

propeller hubs. The FAA is issuing this AD 

to prevent failure of the propeller hub. The 

unsafe condition, if not addressed, could 

result in release of the propeller, damage to 

the airplane, and injury to persons on the 

ground. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

(1) Before the next flight after December 22, 

2020 (the effective date of AD 2020–25–05), 

amend the existing aircraft flight manual by 

inserting the procedure: ‘‘Abnormal propeller 

vibrations: As applicable, reduce engine 

RPM.’’ 

(2) Before the next flight after the effective 

date of this AD, and thereafter, before the 

next flight after any flight where abnormal 

propeller vibrations have been experienced, 

visually inspect propeller hub HO–V 72 ( ) 

( )–( )–( ) for cracks using paragraph 2.1 of 

Hoffmann Propeller GmbH & Co. KG Service 

Bulletin SB E53, Rev. D, dated February 18, 

2021 (the SB). 

(3) Within 20 flight hours after the effective 

date of this AD, perform a non-destructive 

test (NDT) inspection of propeller hub HO– 

V 72 ( ) ( )–()–( ) using paragraph 2.3 of the SB. 

(4) If, during any inspection required by 

paragraph (g)(2) or (3) of this AD, any crack 

is detected, replace propeller hub HO–V 72 

( ) ( )–( )–( ) with a part eligible for installation. 

(5) During each overhaul of propeller hub 

HO–V 72 ( ) ( )–( )–( ) after the effective date 

of this AD, perform an NDT inspection using 

paragraph 2.3 of the SB. 

(h) Definition 

For the purpose of this AD, a ‘‘part eligible 

for installation’’ is a propeller hub HO–V 72 

( ) ( )–( )–( ) with zero hours time since new or 

a propeller hub HO–V 72 ( ) ( )–( )–( ) that has 

passed an NDT inspection using paragraph 

2.3 of the SB. 

(i) Non-Required Actions 

(1) Sending the propeller to Hoffmann for 

investigation, as contained in paragraph 2.1 

of the SB, is not required by this AD. 

(2) Reporting propeller hubs with cracks to 

Hoffmann, as contained in paragraph 2.3 of 

the SB, is not required by this AD. 

(j) Credit for Previous Actions 

You may take credit for the initial visual 

inspection and NDT inspection of the 

propeller hub required by paragraphs (g)(2), 

(3), and (5) of this AD if you performed any 

of these actions before the effective date of 

this AD using Hoffmann Propeller GmbH & 

Co. KG SB E53 Rev. A, dated October 9, 2020; 

Rev. B, dated October 14, 2020; or Rev. C, 

dated December 9, 2020. 

(k) Special Flight Permit 

A special flight permit may be issued in 

accordance with 14 CFR 21.197 and 21.199 

to operate the airplane to a service facility to 

perform the NDT inspection. Special flight 

permits are prohibited to perform the visual 

inspection of the propeller hub. 

(l) Alternative Methods of Compliance 

(AMOCs) 

(1) The Manager, Boston ACO 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. 

(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. 

(m) Related Information 

(1) For more information about this AD, 

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. 

(2) Refer to European Union Aviation 

Safety Agency (EASA) AD 2020–0226R1, 

dated March 31, 2021, for more information. 

You may examine the EASA AD in the AD 

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

searching for and locating it in Docket No. 

FAA–2021–0546. 

(3) For service information identified in 

this AD, contact Hoffmann GmbH & Co. KG, 

Ku ̈pferlingstrasse 9, 83022, Rosenheim, 

Germany; phone: +49 0 8031 1878 0; email: 

info@hoffmann-prop.com; website: https://

hoffmann-prop.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 June 29, 2021. 

Lance T. Gant, 

Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2021–14271 Filed 7–2–21; 8:45 am] 

BILLING CODE 4910–13–P 


jbell on DSKJLSW7X2PROD with PROPOSALS