DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0281; Product Identifier 2018-NE-06-AD]
RIN 2120-AA64

Airworthiness Directives; Hoffmann Propeller GmbH & Co. KG
Propellers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Hoffmann Propeller GmbH & Co. KG model HO-V 62 propellers. This
proposed AD was prompted by the failure of the propeller blade lag
screws. This proposed AD would require removal of the affected
propeller blades and installation of modified propeller blades marked
with change letter "A" or "B." We are proposing this AD to address
the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by August 27, 2018.

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 service information identified in this NPRM, 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. You may view this service
information at the FAA, Engine & Propeller Standards Branch, 1200
District Avenue, Burlington, MA. 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 on the internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2018-
0281; 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),
the regulatory evaluation, any comments received, and other
information. The address for Docket Operations (phone: 800-647-5527) is
listed above. Comments will be available in the AD docket shortly after
receipt.

FOR FURTHER INFORMATION CONTACT: Maureen Maisttison, Aerospace
Engineer, AIR-7B1, FAA, 1200 District Ave, Burlington, MA 01803; phone:
781-238-7076; fax: 781-238-7151; email: maureen.maisttison@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2018-0281;
Product Identifier 2018-NE-06-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this NPRM. We will consider all
comments received by the closing date and may amend this NPRM because
of those comments.

We will post all comments we receive, without change, to http://www.
regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this NPRM.

Discussion

The European Aviation Safety Agency (EASA), which is the Technical
Agent for the Member States of the European Community, has issued EASA
AD 2017-0220, dated November 10, 2017 (referred to hereinafter as "the
MCAI"), to address the unsafe condition on these products. The MCAI
states:

In 1983, occurrences were reported of fatigue failure of
propeller blade lag screws, at rotation speeds between 2950 and 3250
revolutions per minute (RPM) in flight.

This condition, if not detected and corrected, could lead to in-
flight propeller blade detachment, possibly resulting in damage to
the powered sailplane and/or injury to persons on the ground.

To address this potential unsafe condition, Hoffmann issued
Service Bulletin (SB) 4, providing the necessary instructions.
Consequently, LBA Germany issued AD 83-150 (later revised), which
applied only to HO-V 62 propellers with R/L 160T blades, when in
combination with a Limbach L 2000 engine, to require a limitation of
continuous operation to 2 900 RPM, to prohibit aerobatic flights,
calibrate the tachometer, install a placard, and inspection of the
propeller blades. LBA AD 83-150/4 also required overhaul and
replacement of the affected propeller blades with modified blades,
either having 5 lag screws with 12 mm diameter, or 6 screws, and
required implementing a time between overhaul (TBO) of 600 flight
hours (FH).

Since that AD was issued, based on a stress analysis of lag
screws on blades with continuous operating speed above 2 900 RPM, it
was determined that the 6-screws configuration or the 5 screws
configuration with increased strength is necessary to ensure safe
propeller operation. In addition, since the LBA AD applied only to a
limited population (Limbach engine only), many propellers have not
been modified as described in Hoffmann SB 4C. Consequently, Hoffmann
issued SB E34 Revision B, to provide blade replacement instructions.

You may obtain further information by examining the MCAI in the AD
docket on the internet at http://www.regulations.gov by searching for
and locating Docket No. FAA-2018-0281.

Related Service Information

We reviewed Hoffmann Propeller GmbH & Co. KG Service Bulletin (SB)
E34, Rev. B, dated September 18, 2017. The SB describes the
instructions for the removal and installation of the propeller blades.

FAA's Determination

This product has been approved by EASA, and is approved for
operation in the United States. Pursuant to our bilateral agreement
with the European Community, EASA has notified us of the unsafe
condition described in the MCAI and service information referenced
above. We are proposing this AD because we evaluated all the relevant
information provided by EASA and determined the unsafe condition
previously described is likely to exist or develop in other products of
the same type design.

Proposed AD Requirements

This proposed AD would require removal of the affected propeller
blades and installation of the modified propeller blades marked with
change letter "A" or "B" on the blade.

Differences Between This Proposed AD and the MCAI or Service
Information

EASA AD 2017-0220 partially restates the requirements of AD 83-150,
issued on December 21, 1984, by German aviation authority Luftfahrt-
Bundesamt (LBA), which is based on Propellerwerk Hoffmann Rosenheim SB
4, Revision C, dated February 20, 1984. EASA AD 2017-0220 also adds new
requirements based on the issuance of Hoffmann Propeller GmbH & Co. KG
SB E34, Rev. B dated September 18, 2017.

In restating LBA AD 83-150, EASA AD 2017-0220 maintains a
requirement to remove certain propellers from service within 10 flight
hours after December 21, 1984, but not later than 31 March 31, 1985.
Service Bulletin E34 requires a mandatory immediate maximum propeller
rotational speed limitation until the permanent corrective action is
completed, within 50 flight hours. The EASA AD 2017-0220 partially
restated requirements of SB 4. Additionally, Hoffmann Propeller GmbH &
Co. KG SB E34 Revision B and SB 4 Revision C temporarily prohibit
acrobatic flight. EASA AD 2017-0220 also adds a new requirement for a
mandatory maximum propeller rotational speed limitation within 30 days
until the propeller is replaced within 50 flight hours.

This proposed AD does not require a propeller speed limitation but
would require removal of the affected propeller blades and installation
of modified propeller blades within 30 days of the effective date of
this AD.

Costs of Compliance

We estimate that this proposed AD affects 50 propellers installed
on airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

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.

We are 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.

This AD is issued in accordance with authority delegated by the
Executive Director, Aircraft Certification Service, as authorized by
FAA Order 8000.51C. In accordance with that order, issuance of ADs is
normally a function of the Compliance and Airworthiness Division, but
during this transition period, the Executive Director has delegated the
authority to issue ADs applicable to engines, propellers, and
associated appliances to the Manager, Engine and Propeller Standards
Branch, Policy and Innovation Division.

Regulatory Findings

We 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) Is not a "significant rule" under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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 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.

Sec. 39.13 [Amended]

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