DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0881; Project Identifier 2018-CE-024-AD]
RIN 2120-AA64

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 79-
01-03, which applies to certain Piper Aircraft, Inc. (Piper) Model PA-
36-285 airplanes, and AD 83-20-03, which applies to Piper Models PA-36-
285, PA-36-300, and PA-36-375 airplanes. AD 79-01-03 requires
repetitive inspections of the spar carry through assembly until it is
replaced with a different part numbered spar carry through assembly. AD
83-20-03 establishes life limits for the wing spar structural
components. Since the FAA issued AD 79-01-03 and AD 83-20-03, the FAA
identified inspection and life limit requirements that were
inadvertently omitted from those ADs. This proposed AD would retain the
requirements in AD 79-01-03 and AD 83-20-03 and require the spar carry
through assembly inspection from AD 79-01-03 for additional airplanes
and add life limits for certain wing structural components previously
omitted from AD 83-20-03 for certain serial numbered airplanes. 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 May 7,
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 Piper
Aircraft, Inc., 2926 Piper Drive, Vero Beach, FL 32960; phone: (772)
567-4361; website: https://www.piper.com. You may view this service
information at the FAA, Airworthiness Products Section, Operational
Safety Branch, 901 Locust, Kansas City, MO 64106. For information on
the availability of this material at the FAA, call (816) 329-4148.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-0881; 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: Dan McCully, Aviation Safety Engineer,
FAA, Atlanta ACO Branch, 1701 Columbia Avenue, College Park, GA 30337;
phone: (404) 474-5548; fax: (404) 474-5606; email:
william.mccully@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 the ADDRESSES section. Include "Docket No. FAA-2020-0881;
Project Identifier 2018-CE-024-AD." 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 received 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 Dan
McCully, Aviation Safety Engineer, FAA, Atlanta ACO Branch, 1701
Columbia Avenue, College Park, GA 30337. 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 79-01-03, Amendment 39-3383 (44 FR 36, January 2,
1979), Docket No. 78-EA-69 (AD 79-01-03), for certain Piper Model PA-
36-285 airplanes. AD 79-01-03 requires repetitive inspections of spar
carry through assembly part number (P/N) 97370-00, with repair as
necessary, until the spar carry through assembly is replaced with P/N
76824-02. AD 79-01-03 was prompted by reports of cumulative damage to
the wing spar carry through assembly, which resulted from fatigue
testing and other field evidence of movement between the leg of the
spar cap and the spar web. The FAA issued AD 79-01-03 to prevent
hazards in flight associated with damage of the wing spar carry through
assembly.

The FAA also issued AD 83-20-03, Amendment 39-4739 (48 FR 45535,
October 6, 1983), Docket No. 83-CE-23-AD (AD 83-20-03), for Piper
Models PA-36-285, PA-36-300, and PA-36-375 airplanes. AD 83-20-03
establishes life limits for certain wing structural components. AD 83-
20-03 was prompted by manufacturer laboratory fatigue tests of the wing
structure that identified the need to establish a service life limit
for the wing structural components. The FAA issued AD 83-20-03 to
prevent failure of the wing structural components because of fatigue
damage.

Actions Since AD 79-01-03 and AD 83-20-03 Were Issued

Since the FAA issued AD 79-01-03 and AD 83-20-03, the FAA
identified inconsistencies between the two ADs and the airplanes' type
certificate. The FAA determined that the life limits for the spar carry
through assembly, P/N 97370-00 or 76824-02, were inadvertently omitted
from AD 83-20-03 for certain airplanes. The FAA is issuing this NPRM to
add the life limit for the spar carry through assembly for Models PA-
36-285 and PA-36-300 airplanes, serial numbers 36-7660123 through 36-
8160023, and Model PA-36-375 airplanes, serial numbers 36-7802001
through 36-8302025. The FAA also determined the repetitive inspections
of the spar carry through assembly required by AD 79-01-03 should apply
to both Model PA-36-285 and Model PA-36-300 airplanes until the life
limit replacement of the spar carry through assembly with P/N 76824-02.
After the initial life limit replacement of the wing spar carry through
assembly required by AD 83-20-03 (P/N 97370-00 with P/N 76824-02), the
inspections required by AD 79-01-03 are no longer be required. In this
NPRM, the FAA proposes to supersede both of those ADs.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Piper Aircraft, Inc., Service Bulletin No. 552A,
dated August 3, 2018 (Piper SB No. 552A); Piper Aircraft PA-36, Pawnee
Brave Kit 764-394, Right Wing Main Spar Caps Replacement, dated June 9,
2012 (Piper Kit 764-394); and Piper Aircraft PA-36, Pawnee Brave Kit
764-393, Left Wing Main Spar Caps Replacement, dated June 9, 2012
(Piper Kit 764-393). Piper SB No. 552A applies to Models PA-36-285 and
PA-36-300 airplanes and contains procedures for repetitively inspecting
wing spar carry through assembly P/N 97370-00. Piper Kit 764-394
identifies the applicable parts and specifies procedures for replacing
the right wing main spar caps, which includes the attachment bolts and
wing carry through spar fittings and assembly. Piper Kit 764-393
identifies the applicable parts and specifies procedures for replacing
the left wing main spar caps, which includes the attachment bolts and
wing carry through spar fittings and assembly. 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 the ADDRESSES section.

Other Related Service Information

The FAA also reviewed Piper Aircraft Corporation Service Bulletin
No. 552, dated February 3, 1978 (Piper SB No. 552). Piper SB No. 552
contains the same procedures as Piper SB No. 552A, but Piper SB No. 552
only applies to Model PA-36-285 airplanes.

Proposed AD Requirements in This NPRM

This proposed AD would retain all of the requirements of AD 79-01-
03 and AD 83-20-03 but would apply some of the requirements to
additional serial-numbered airplanes.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 123 airplanes of U.S. registry.

The FAA estimates the following costs to comply with this proposed
AD:

Estimated Costs

* The wing carry through spar fitting, P/N 97713-03, is included in the wing carry
through spar assembly, P/N 76824-02.

** The replacement for the wing spar fitting P/N 97712-00 and the replacement
for spar assembly P/Ns 97701-00 and 97701-01 are included in Piper Kit 764-393
and Piper Kit 764-394.

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 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 to the extent
that it justifies making a regulatory distinction, 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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by:

a. Removing Airworthiness Directive 79-01-03, Amendment 39-3383 (44 FR
36, January 2, 1979), Docket No. 78-EA-69; and Airworthiness Directive
83-20-03, Amendment 39-4739 (48 FR 45535, October 6, 1983), Docket No.
83-CE-23-AD; and

b. Adding the following new airworthiness directive: