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PROPOSED AD PIPER AIRCRAFT, INC.: Docket No. FAA-2020-1006; Project Identifier 2019-CE-047-AD.
(a) COMMENTS DUE DATE

    The FAA must receive comments on this airworthiness directive (AD)  by
    November 1, 2021.

(b) AFFECTED ADS

    This AD replaces AD 78-02-03  [Reg. Docket No. 77-EA-81, Amendment  39
    -3128] (43 FR 3079, January 23, 1978) (AD 78-02-03).

(c) APPLICABILITY

    This AD applies  to Piper Aircraft,  Inc., Model PA-23-250  airplanes,
    serial  numbers  27-7654001 through  27-7954121,  certificated in  any
    category.

(d) SUBJECT

    Joint Aircraft System Component (JASC) Code 5510 Horizontal Stabilizer
    Structure.

(e) UNSAFE CONDITION

    This AD was prompted by reports of cracks developing on the stabilator
    structure. The  FAA is  issuing this  AD to  prevent weakening  of the
    stabilator  structure  and  to  detect  and  correct  cracks  on   the
    stabilator tip tube and weight assembly. The unsafe condition, if  not
    addressed, could cause weakening of the complete structure and lead to
    loss of the trim tab and  counter balance weight, which may result  in
    reduced airplane control.

(f) COMPLIANCE

    Comply  with this  AD within  the compliance  times specified,  unless
    already done.

(g) PREVIOUSLY REQUIRED ACTIONS RETAINED FROM AD 78-02-03

(1) Within 50 hours  time-in-service  (TIS)  after  January 26, 1978  (the
    effective date of AD 78-02-03), do the following inspections and modi-
    fications.

(i) For airplanes  with serial numbers 27-7654001 through 27-7754054,  in-
    spect both stabilator tip ribs for missing rivets and missing tube and
    weight assembly attachment screws and if necessary alter in accordance
    with Piper Service Bulletin (SB) 547, dated March 1, 1977.

(ii) For airplanes  with serial numbers 27-7654001 through 27-7754127, 27-
     7754130, 27-7754131,  27-7754133 through  27-7754136, and  27-7754138
     through 27-7754144, replace the right and left stabilator tab forward
     inboard rib/horn assemblies by installing Piper Kit 761 143 or equiv-
     alent kit in accordance with Piper SB 569, dated August 24, 1977.

(iii) For  airplanes  with  serial  numbers  27-7654001 through 27-7754041
      equipped with stabilators Piper part number (P/N) 15658-2,  15658-3,
      15658-22 or 15658-23, reinforce the mounting of the stabilator  tube
      and weight assemblies by installing additional nose-ribs with  Piper
      Kit  761 141  or equivalent  kit in  accordance  with  Piper Service
      Letter 807A, dated September 8, 1977.

(2) Before further flight  after completing the alterations  in paragraphs
    (g)(1)(ii) and (iii) of this AD, balance the stabilator.

(h) INSPECTION OF STABILATOR TIP TUBE AND WEIGHT ASSEMBLY

    Within 10 hours TIS after the effective date of this AD or within  100
    hours TIS after completing  the last inspection required  by paragraph
    (a)  of  AD  78-02-03,  whichever  occurs  later,  and  thereafter  at
    intervals not  to exceed  100 hours  TIS, inspect  the left  and right
    stabilator  balance  weight  assemblies for  cracks  and  complete any
    necessary repairs by following Parts  I and II of the  Instructions in
    Piper SB No. 540B, dated February 9, 2021, except you are not required
    to  contact  Piper  for   repair  instructions.  Instead,  repair   in
    accordance with FAA-approved procedures.

(i) CREDIT FOR PREVIOUS ACTIONS

    You may take credit  for the initial inspection and corrective actions
    required by paragraph (h)  of  this  AD if you performed those actions
    before the effective date  of  this  AD  using Piper SB No. 540, dated
    January 4, 1977, or SB No. 540A, dated October 20, 1980.

(j) ALTERNATIVE METHODS OF COMPLIANCE (AMOCS)

(1) The  Manager,  Atlanta 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.

(3) For service information  that  contains  steps that are labeled as Re-
    quired for Compliance (RC), the following provisions apply.

(i) The steps labeled as RC,  including substeps  under an RC step and any
    figures identified in an RC step,  must be done to comply with the AD.
    An AMOC is required for any deviations to RC steps, including substeps
    and identified figures.

(ii) Steps not labeled as RC  may be deviated  from using accepted methods
     in accordance with the  operator's maintenance or inspection  program
     without  obtaining  approval  of  an  AMOC,  provided  the  RC steps,
     including  substeps  and identified  figures,  can still  be  done as
     specified,  and  the  airplane  can  be  put  back  in  an  airworthy
     condition.

(k) RELATED INFORMATION

(1) For more information about this AD,  contact  John Marshall,  Aviation
    Safety  Engineer,  Atlanta  ACO  Branch,  FAA,  1701 Columbia  Avenue,
    College Park, GA 30337;  phone: (404) 474-5524;  fax:  (404) 474-5605;
    email: john.r.marshall@faa.gov.

(2) For service information identified in this AD, contact Piper Aircraft,
    Inc., 2926 Piper Drive, Vero  Beach, FL 32960; phone: (772)  299-2141;
    website: https://www.piper.com/. You may view this referenced  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.

Issued on September 9, 2021.  Ross Landes,  Deputy Director for Regulatory
Operations,  Compliance & Airworthiness Division,  Aircraft  Certification
Service.

DATES: The FAA must receive comments  on this proposed AD  by  November 1,
2021.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1006; Project Identifier 2019-CE-047-AD]
RIN 2120-AA64

Airworthiness Directives; Piper Aircraft, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 78-
02-03, which applies to all Piper Aircraft, Inc. (Piper), Model PA-23-
250 airplanes. AD 78-02-03 requires repetitively inspecting the
stabilator tip tube and weight assemblies for cracks, inspecting for
missing rivets and screws, replacing the forward rib/horn assemblies,
and reinforcing the mounting. Since AD 78-02-03 was issued, Piper
developed a newly-designed stabilator, which is not subject to the
unsafe condition, and revised its service information. This proposed AD
would retain the actions of AD 78-02-03, but would reduce the
applicability and require the actions in the revised service
information. 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 November 1,
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)
299-2141; 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-2020-1006; 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: John Marshall, Aviation Safety
Engineer, Atlanta ACO Branch, FAA, 1701 Columbia Avenue, College Park,
GA 30337; phone: (404) 474-5524; fax: (404) 474-5605; email:
john.r.marshall@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 Number FAA-2020-1006; Project
Identifier 2019-CE-047-AD" 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 received about this NPRM.

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 John
Marshall, Aviation Safety Engineer, Atlanta ACO Branch, FAA, 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 78-02-03 [Reg. Docket No. 77-EA-81, Amendment 39-
3128] (43 FR 3079, January 23, 1978) (AD 78-02-03), for all Piper Model
PA-23-250 airplanes. AD 78-02-03 was prompted by cracks found on the
stabilator structure during routine inspections, including cracks in
the tip balance weight, abnormal trim tab horn bushing wear, and skin
and nose rib cracks. The FAA issued AD 78-02-03 to prevent weakening of
the stabilator structure and loss of the trim tab and counter balance
weight, which could result in reduced airplane control.

For all Model PA-23-250 airplanes, AD 78-02-03 requires
repetitively inspecting both the stabilator tip tube and the weight
assemblies for cracks, with follow-on alterations or replacements as
necessary, in accordance with Piper Service Bulletin (SB) No. 540,
dated January 4, 1977 (Piper SB 540). For different groups of serial-
numbered airplanes, AD 78-02-03 requires a one-time inspection of the
stabilator tip ribs for missing rivets and missing tube and weight
assembly attachment screws with alteration as necessary, replacement of
the right and left stabilator tab forward inboard rib/horn assemblies,
and/or reinforcement of the mounting of the stabilator tube and weight
assemblies. The repetitive inspections in AD 78-02-03 for all serial-
numbered airplanes have no terminating action and are required
regardless of any corrective actions performed.

Actions Since AD 78-02-03 Was Issued

Since the FAA issued AD 78-02-03, Piper changed the design of the
stabilator structure. Airplanes beginning with serial number 27-7954122
were manufactured with the stabilator design change and are not subject
to the unsafe condition addressed by AD 78-02-03. The FAA determined
the applicability of AD 78-02-03 should be revised to exclude those
later-manufactured airplanes.

In addition, Piper revised SB 540, the service bulletin required by
AD 78-02-03 for the repetitive inspections of the stabilator tip tube
and the weight assemblies. Piper SB 540B, dated February 9, 2021 (Piper
SB 540B), reduces the applicability of the affected serial numbers and
contains separate instructions for inspecting and repairing airplanes
with a modified tube and weight assembly or with a stabilizer balance
weight replacement kit part number (P/N) 763 987.

Related Service Information Under 1 CFR Part 51

The FAA reviewed the following service documents proposed for
compliance with this NPRM:

Piper SB No. 547, dated March 1, 1977, which contains
instructions for inspecting the stabilator tip rib;

Piper SB No. 569, dated August 24, 1977, which contains
information for replacing the stabilator tab horn;

Piper Service Letter No. 807A, dated September 8, 1977,
which contains information for installing the stabilator outboard nose
rib; and

Piper SB No. 540B, February 9, 2021, which contains
instructions for inspecting the stabilator tip tube and weight assembly
and addressing any cracks found.

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.

Other Related Service Information

The FAA reviewed the following documents for information related to
this NPRM:

Piper SB 540, which contains instructions for inspecting
and reinforcing the stabilator tip tube and weight assembly; and

Piper Aztec Service Manual, Part Number 753-564, dated
January 1, 2009. Paragraphs 4-65 through 4-67 of this manual contain
procedures for checking control surface balance.

FAA's Determination

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

Proposed AD Requirements in This NPRM

This proposed AD would retain all of the requirements of AD 78-02-
03 but would reduce the applicability and update some of the service
information that would be required for compliance.

Differences Between This Proposed AD and the Service Information

Piper SB 540B specifies contacting Piper for repair instructions.
This proposed AD would require contacting the FAA for an approved
repair method instead.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 625 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
Inspect the stabilator tip tube and weight assembly. 0.5 work-hour x $85 per hour = $42.50 Not applicable $42.50 per inspection cycle $26,562.50 per inspection cycle
Inspect the stabilator tip ribs. 0.5 work-hour x $85 per hour = $42.50 Not applicable $42.50 $26,562.50
Replace the stabilator tab forward rib/horn assemblies. 4 work-hours x $85 per hour = $340 $817 $1,157 $723,125
Install additional nose ribs. 1 work-hour x $85 per hour = $85 $367 $452 $282,500

The FAA estimates the following costs to do any necessary repairs
or replacements that would be required based on the results of the
proposed inspection. The FAA has no way of determining the number of
airplanes that might need these repairs or replacements:

On-Condition Costs

Action Labor cost Parts cost Cost per product
Repair stabilator tip tube and weight assemblies (airplanes without kit P/N 763 987). 4 work-hours x $85 per hour = $340 $80 $420
Install missing stabilator tip rib rivets and/or the stabilator tip tube and weight assembly attachment screws. 1 work hour x $85 per hour = $85 39 124
Balance stabilator 5 work-hours x $85 per hour = $425 Not applicable 425

For airplanes with kit P/N 763 987, the cost to repair cracking may
vary significantly from airplane to airplane, and therefore the FAA has
no way of determining an estimated cost.

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 this 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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by:

a. Removing Airworthiness Directive 78-02-03 [Reg. Docket No. 77-EA-81,
Amendment 39-3128] (43 FR 3079, January 23, 1978); and

b. Adding the following new airworthiness directive: