Airworthiness Directives; Hoffmann GmbH & Co. KG Propellers

[Federal Register Volume 87, Number 210 (Tuesday, November 1, 2022)]
[Rules and Regulations]
[Pages 65670-65673]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-23716]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0980; Project Identifier MCAI-2022-00448-P; 
Amendment 39-22212; AD 2022-21-13]
RIN 2120-AA64


Airworthiness Directives; Hoffmann GmbH & Co. KG Propellers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2021-23-17 
for all Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. AD 
2021-23-17 required amending the existing aircraft flight manual (AFM) 
by inserting abnormal propeller vibration instructions, 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. Since the FAA 
issued AD 2021-23-17, further investigation by the manufacturer 
revealed that cracks found on propeller hubs likely resulted from 
propeller blade retention nuts that were not tightened using published 
service information during blade installation. This AD is prompted by 
reports of cracks at different positions on two affected propeller 
hubs. This AD retains the required actions of AD 2021-23-17. This AD 
also requires a maintenance records review and, depending on the 
results of the maintenance records review, tightening of each propeller 
blade retention nut to specific torque values. Depending on the results 
of the maintenance records review, this AD requires physically 
inspecting the propeller blade for shake. If any axial play is detected 
during the performance of the inspection, this AD requires the removal 
of the propeller from service and the performance of an NDT inspection 
of the propeller hub, and depending on the NDT inspection results, 
replacement of the propeller hub with a part eligible for installation. 
The FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective December 6, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of December 6, 
2022.
    The Director of the Federal Register approved the incorporation by 
reference of a certain other publication listed in this AD as of 
January 10, 2022 (86 FR 68905, December 6, 2021).

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2022-0980; 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, the mandatory continuing airworthiness 
information (MCAI), any comments received, and other information. The 
address for Docket Operations is U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
    <bullet> For Hoffmann service information identified in this final 
rule, contact Hoffmann GmbH & Co. KG, K[uuml]pferlingstrasse 9, 83022, 
Rosenheim, Germany; phone: +49 0 8031 1878 0; email: prop.com">hoffmann-prop.com">info@prop.com">hoffmann-prop.com; website: prop.com">hoffmann-prop.com.
    <bullet> 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 (817) 222-5110. It is 
also available at regulations.gov under Docket No. FAA-2022-0980.

FOR FURTHER INFORMATION CONTACT: Michael Schwetz, Aviation Safety 
Engineer, Boston ACO Branch, FAA, 1200 District Avenue, Burlington, MA 
01803; phone: (781) 238-7761; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2021-23-17, Amendment 39-21815 (86 FR 
68905, December 6, 2021) (AD 2021-23-17). AD 2021-23-17 applied to all 
Hoffmann GmbH & Co. KG model HO-V 72 propellers. AD 2021-23-17 required 
amending the existing AFM by inserting abnormal propeller vibration 
instructions, 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. The FAA issued AD 
2021-23-17 to prevent failure of the propeller hub.
    The NPRM published in the Federal Register on August 01, 2022 (87 
FR 46903). The NPRM was prompted by EASA AD 2022-0061, dated April 4, 
2022 (referred to after this as ``the MCAI''), issued by the European 
Union

[[Page 65671]]

Aviation Safety Agency (EASA), which is the Technical Agent for the 
Member States of the European Union. 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. 
Subsequent investigation determined that improper tightening of 
blade nuts has caused or contributed to those events.
    This condition, if not detected and corrected, could lead to in-
flight propeller detachment, possibly resulting in damage to the 
aeroplane and/or injury to persons on the ground.
    To address this potential unsafe condition, Hoffmann Propeller 
issued the SB, providing applicable instructions, and EASA issued 
Emergency AD 2020-0226-E (later revised [to EASA AD 2020-0226R1]) to 
require inspections of affected parts and, depending on findings, 
replacement. That AD also required, for certain aeroplanes, 
amendment of the applicable Aircraft Flight Manual (AFM).
    Since that [EASA] AD was issued, further investigation revealed 
that not all propeller blade nuts were tightened in accordance with 
the Hoffman Propeller blade nut tightening procedure B2.23 which 
requires a certain over-torquing and loosening of the blade nut to 
limit a preload reduction due to material settlement. Prompted by 
this development, Hoffmann Propeller issued SB057 (incorporating 
blade nut tightening procedure B2.23) providing torquing 
instructions, and SB58 providing instructions for setting correct 
counterweight angles. Additionally, Hoffmann Propeller issued the 
torque tightening SB (referencing SB57 and SB58) providing 
inspections and corrective action instructions.
    For the reasons described above, this [EASA] AD retains the 
requirements of EASA AD 2020-0226R1, which is superseded, and 
requires additional blade checks, inspections, and re-tightening of 
the propeller blade nuts

    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2022-0980.
    In the NPRM, the FAA proposed to retain all of the requirements of 
AD 2021-23-17. In the NPRM, the FAA also proposed to require a 
maintenance records review and, depending on the results of the 
maintenance records review, tightening of each propeller blade 
retention nut to specified torque values. Depending on the results of 
the maintenance records review, the NPRM also proposed to require 
physically inspecting the propeller blade for shake. If any axial play 
is detected during inspection, the NPRM proposed to require the removal 
of the propeller from service and the performance of an NDT inspection 
of the propeller hub, and depending on the NDT inspection results, 
replacement of the propeller hub with a part eligible for installation.

Discussion of Final Airworthiness Directive

Comments

    The FAA received no comments on the NPRM or on the determination of 
the costs.

Conclusion

    These products have been approved by the aviation authority of 
another country and are approved for operation in the United States. 
Pursuant to the FAA's bilateral agreement with this State of Design 
Authority, it has notified the FAA of the unsafe condition described in 
the MCAI referenced above. The FAA reviewed the relevant data and 
determined that air safety requires adopting this AD as proposed. 
Accordingly, the FAA is issuing this AD to address the unsafe condition 
on these products. Except for minor editorial changes, and the removal 
of the reference to Hoffmann Propeller Service Bulletin SB059 B, dated 
February 23, 2022, from paragraph (j)(2), this AD is adopted as 
proposed in the NPRM. None of the changes will increase the economic 
burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed the following service information:
    <bullet> Hoffmann Propeller Service Bulletin SB057 C, dated 
February 22, 2022. This service bulletin (SB) specifies procedures for 
tightening the propeller blade retention nut.
    <bullet> Hoffmann Propeller Service Bulletin SB059 B, dated 
February 23, 2022. This SB specifies procedures for tightening the 
propeller blade retention nut with the correct torque and inspecting 
the propeller blade for shake.
    <bullet> Hoffmann Propeller GmbH & Co. KG Service Bulletin SB E53 
Rev. D, dated February 18, 2021, which was previously approved by the 
Director of the Federal Register for incorporation by reference on 
January 10, 2022 (86 FR 68905, December 6, 2021). This SB describes 
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.

Other Related Service Information

    The FAA also reviewed the following service information:
    <bullet> Hoffmann Propeller Service Bulletin SB058 A, dated 
February 2, 2022. This SB specifies the updated definition of the 
counterweight angle.

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
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Amend AFM.............................  1 work-hour x $85 per                 $0             $85          $2,975
                                         hour = $85.
Visually inspect propeller hub........  1 work-hour x $85 per                  0              85           2,975
                                         hour = $85.
NDT inspect propeller hub.............  8 work-hours x $85 per                 0             680          23,800
                                         hour = $680.
Review maintenance records............  0.5 work-hours x $85 per               0           42.50        1,487.50
                                         hour = $42.50.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary actions 
that are required based on the results of the inspections. The agency 
has no way of determining the number of aircraft that might need these 
replacements:

[[Page 65672]]



                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace propeller hub.........................  5 work-hours x $85 per hour =             $1,600          $2,025
                                                 $425.
Inspect propeller blade for shake.............  0.25 work-hours x $85 per hour =               0           21.25
                                                 $21.25.
Tighten propeller blade retention nuts........  2 work-hours x $85 per hour =                  0             170
                                                 $170.
----------------------------------------------------------------------------------------------------------------

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 has determined that 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,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will 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 Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive 2021-23-17, Amendment 39-21815 (86 
FR 68905, December 6, 2021); and
0
b. Adding the following new airworthiness directive:

2022-21-13 Hoffmann GmbH & Co. KG: Amendment 39-22212; Docket No. 
FAA-2022-0980; Project Identifier MCAI-2022-00448-P.

(a) Effective Date

    This airworthiness directive (AD) is effective December 6, 2022.

(b) Affected ADs

    This AD replaces AD 2021-23-17, Amendment 39-21815 (86 FR 68905, 
December 6, 2021) (AD 2021-23-17).

(c) Applicability

    This AD applies to 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 already done.

(g) Required Actions

    (1) Before the next flight after December 22, 2020 (the 
effective date of AD 2020-25-05, Amendment 39-21347 (85 FR 78702, 
December 7, 2020)), amend the emergency or abnormal procedures 
section of the existing aircraft flight manual by inserting this 
text: ``Abnormal propeller vibrations: As applicable, reduce engine 
RPM.''
    (2) Before the next flight after January 10, 2022 (the effective 
date of AD 2021-23-17), 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 (Hoffmann 
Propeller SB E53 Rev. D).
    (3) Within 20 flight hours (FHs) after January 10, 2022 (the 
effective date of AD 2021-23-17), perform a non-destructive test 
(NDT) inspection of propeller hub HO-V 72 ( ) ( )-( )-( ) using 
paragraph 2.3 of Hoffmann Propeller SB E53 Rev. D.
    (4) During each overhaul of propeller hub HO-V 72 ( ) ( )-( )-( 
) after January 10, 2022 (the effective date of AD 2021-23-17), 
perform an NDT inspection using paragraph 2.3 of Hoffmann Propeller 
SB E53 Rev. D.
    (5) Within 30 days after the effective date of this AD, review 
the maintenance records to confirm the propeller blade retention 
nuts were tightened at the last in-shop maintenance visit to the 
torque values in paragraph 5 of Hoffmann Propeller Service Bulletin 
SB057 C, dated February 22, 2022 (Hoffmann Propeller SB057 C).
    (6) If, during the records review required by paragraph (g)(5) 
of this AD, it is determined that the propeller blade retention nuts 
were not tightened to the torque values in paragraph 5 of Hoffmann 
Propeller SB057 C, or it cannot be confirmed if the propeller blade 
retention nuts were tightened to the torque values in paragraph 5 of 
Hoffmann Propeller SB057 C, perform the following actions:
    (i) Within 90 FHs after the effective date of this AD, tighten 
each propeller blade retention nut to the torque values in paragraph 
5 of Hoffmann Propeller SB057 C, using paragraphs 6 and 7 of 
Hoffmann Propeller Service Bulletin SB059 B, dated February 23, 
2022.
    (ii) Before the next flight after the effective date of this AD 
and, thereafter, before each flight until the propeller blade 
retention nut is tightened to the torque values in paragraph 5 of 
Hoffmann Propeller SB057 C, as required by paragraph (g)(6)(i) of 
this AD, confirm that there is no axial play in the blade retention 
system by inspecting the propeller blade for shake. If any axial 
play is detected, remove the propeller from service and perform an 
NDT inspection of the propeller hub using paragraph 2.3 of Hoffmann 
Propeller SB E53 Rev. D.
    (7) If, during any inspection required by paragraph (g)(2), (3), 
(4) or (6)(ii) of this AD, any crack is detected, replace 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

[[Page 65673]]

has passed an NDT inspection using paragraph 2.3 of Hoffmann 
Propeller SB E53 Rev. D.

(i) Non-Required Actions

    (1) Sending the propeller to Hoffmann for investigation, as 
contained in paragraph 2.1 of Hoffmann Propeller SB E53 Rev. D, is 
not required by this AD.
    (2) Reporting propeller hubs with cracks to Hoffmann, as 
contained in paragraph 2.3 of Hoffmann Propeller SB E53 Rev. D, is 
not required by this AD.

(j) Credit for Previous Actions

    (1) You may take credit for the initial visual inspection and 
NDT inspection of the propeller hub required by paragraphs (g)(2), 
(3), and (4) of this AD if you performed any of these actions before 
January 10, 2022 (the effective date of AD 2021 23-17) 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.
    (2) You may take credit for the records review to confirm the 
propeller blade retention nuts were tightened to the torque values 
as required by paragraph (g)(5) of this AD, and the tightening of 
each propeller blade retention nut as required by paragraph 
(g)(6)(i) of this AD if you performed any of these actions before 
the effective date of this AD during the last in-shop maintenance 
visit using Hoffmann Propeller Service Bulletin SB057 B, dated 
February 8, 2022; or Hoffmann Propeller Service Bulletin SB059 A, 
dated February 11, 2022.

(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 paragraph (m)(1) of this AD.
    (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) Additional 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; email: [email protected].
    (2) Refer to European Union Aviation Safety Agency (EASA) AD 
2022-0061, dated April 4, 2022, for related information. This EASA 
AD may be found in the AD docket at regulatFAA-2022-0980.

 (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.
    (3) The following service information was approved for IBR on 
December 6, 2022.
    (i) Hoffmann Propeller Service Bulletin SB057 C, dated February 
22, 2022.
    (ii) Hoffmann Propeller Service Bulletin SB059 B, dated February 
23, 2022.
    (4) The following service information was approved for IBR on 
January 10, 2022 (86 FR 68905, December 6, 2021).
    (i) Hoffmann Propeller GmbH & Co. KG Service Bulletin SB E53 
Rev. D, dated February 18, 2021.
    (ii) Reserved.
    (5) For Hoffmann service information identified in this AD, 
contact Hoffmann GmbH & Co. KG, K[uuml]pferlingstrasse 9, 83022, 
Rosenheim, Germany; phone: +49 0 8031 1878 0; email: prop.com">hoffmann-prop.com">info@prop.com">hoffmann-prop.com; website: prop.com">hoffmann-prop.com.
    (6) 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 (817) 222-5110.
    (7) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on October 6, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-23716 Filed 10-31-22; 8:45 am]
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