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2020-25-05 HOFFMANN GMBH & CO. KG:
Amendment 39-21347; Docket No. FAA-2020-1104; Project Identifier MCAI-2020-01421-P.

(a) EFFECTIVE DATE

    This airworthiness directive (AD) is effective December 22, 2020.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to all Hoffmann GmbH & Co. KG (Hoffmann) model 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 al-
    ready done.

(g) REQUIRED ACTIONS

(1) Before the next flight after the effective date of this AD,  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 there-
    after,  before the next flight after any flight where abnormal propel-
    ler 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. B, dated October
    14, 2020 (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 para-
    graph 2.3 of the SB.

(6) Before exceeding 30 years since the date of manufacture,  or within 30
    days after the effective date of this AD,  whichever occurs later, re-
    place propeller hub HO-V 72 ( ) ( )-( )-( )  with a part  eligible for
    installation.

(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 accumulated fewer
    than 30 years since the date of manufacture  and has passed an NDT in-
    spection 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 inspec-
    tion 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.

(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 in-
    spector, 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 Ave, 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 2020-0226-E,
    dated October 16, 2020, 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-2020-1104.

(n) MATERIAL INCORPORATED BY REFERENCE

(1) The Director of the Federal Register  approved  the  incorporation  by
    reference (IBR) of  the service information  listed in this  paragraph
    under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use  this service information as applicable to do the actions
    required by this AD, unless the AD specifies otherwise.

(i) Hoffmann Propeller GmbH & Co. KG  (Hoffmann)  Service Bulletin SB E53,
    Rev. B, dated October 14, 2020.

(ii) [Reserved]

(3) For Hoffmann service information identified in this AD,  contact Hoff-
    mann Propeller GmbH & Co. KG, Sales and Service,  Kupferlingstrasse 9,
    83022,  Rosenheim, Germany;  phone: +49 (0) 8031 1878 0;  fax: +49 (0)
    8031 1878 78; email: info@hoffmann-prop.com; website: https://hoffmann
    -prop.com/.

(4) 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.

(5) You may view this service information  that is incorporated  by refer-
    ence at the National Archives and Records Administration  (NARA).  For
    information  on  the availability  of  this material  at  NARA, email:
    fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-
    register/cfr/ibr-locations.html.

Issued on November 30, 2020.  Lance T. Gant,  Director,  Compliance & Air-
worthiness Division, Aircraft Certification Service.

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.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1104; Project Identifier MCAI-2020-01421-P;
Amendment 39-21347; AD 2020-25-05]
RIN 2120-AA64

Airworthiness Directives; Hoffmann GmbH & Co. KG Propellers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. This AD was
prompted by reports of cracks at different positions on two affected
propeller hubs. This AD requires amending the existing aircraft flight
manual (AFM) with abnormal propeller vibration instructions. This AD
requires visual inspection and non-destructive 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.
This AD 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 this AD, whichever occurs later. The FAA is issuing
this AD to address the unsafe condition on these products.

DATES: This AD is effective December 22, 2020.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of December 22,
2020.
The FAA must receive comments on this AD by January 21, 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 final rule, contact
Hoffmann Propeller GmbH & Co. KG, Sales and Service,
Kupferlingstrasse 9, 83022, Rosenheim, Germany; phone: +49 (0)
8031 1878 0; fax: +49 (0) 8031 1878 78; email: info@hoffmann-prop.com;
website: https://hoffmann-prop.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. It is also available at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-1104.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-1104; 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 street address for the
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:

Background

The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Community, has
issued EASA AD 2020-0226-E, dated October 16, 2020 (referred to after
this as ``the MCAI''), to address an unsafe condition for the specified
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 [service bulletin], providing applicable instructions.
For the reasons described above, this [EASA] AD requires
inspections of affected parts and, depending on findings,
replacement, and introduces a life limit for affected parts. This
[EASA] AD also requires, for certain aeroplanes, amendment of the
applicable Aircraft Flight Manual (AFM).

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-2020-1104.

FAA's Determination

The FAA is issuing this AD because the agency has 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. B, dated October 14, 2020. 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.

AD Requirements

This AD requires amending the existing AFM with abnormal propeller
vibration instructions. This AD 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. This AD 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 this AD, whichever occurs later.

Differences Between the AD and the MCAI


EASA AD 2020-0226-E, dated October 16, 2020, 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 AD
applies to all Hoffmann model HO-V 72 propellers regardless of their
use.

EASA AD 2020-0226-E, dated October 16, 2020, defines the life of
the propeller hub as 30 years since the first installation on the
airplane. This AD defines the life of the propeller hub as 30 years
since the date of manufacture because the installation history of the
propeller might be unknown.

Interim Action

The FAA considers this AD interim action. This unsafe condition is
still under investigation by the manufacturer and, depending on the
results of that investigation, the FAA may consider further rulemaking
action.

Justification for Immediate Adoption and Determination of the Effective
Date


Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
the public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies foregoing notice and comment prior to adoption of this rule.
During a scheduled inspection, a crack was found by an operator on a
propeller hub. A second crack was found on another propeller hub during
an unscheduled inspection by an operator after abnormal vibrations
occurred in-flight. Hoffmann Propeller immediately issued service
information instructing operators to visually inspect the hub for
cracks before the next flight while the cause of the cracks are under
investigation.
A crack in the propeller hub can result in the loss of a propeller
blade, resulting in an imbalance in the entire engine which can render
the aircraft uncontrollable. The FAA considers a crack in the propeller
hub an urgent safety issue that requires an immediate action to avoid
potential loss of the airplane. Accordingly, notice and opportunity for
prior public comment are impracticable and contrary to the public
interest pursuant to 5 U.S.C. 553(b)(3)(B). In addition, the FAA finds
that good cause exists pursuant to 5 U.S.C. 553(d) for making this
amendment effective in less than 30 days, for the same reasons the FAA
found good cause to forego notice and comment.

Comments Invited

The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include the docket number FAA-2020-1104 and Project
Identifier MCAI-2020-01421-P at the beginning of your comments. The
most helpful comments reference a specific portion of the final rule,
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 final rule 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 final rule.

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 AD 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 AD, 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 AD. 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.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 35 propellers installed on
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
Amend AFM 1 work-hour x $85 per hour = $85
$0
$85
$2,975
Visually inspect propeller hub 1 work-hour x $85 per hour= $85
0
85
2,975
NDT inspect propeller hub 8 work-hours x $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
inspections. 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 x $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 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 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, and
(2) Will not affect intrastate aviation in Alaska.

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.

Sec. 39.13 [Amended]


2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive: