DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-1006; Project Identifier 2019-CE-047-AD]
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
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
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
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:
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.
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
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
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
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.
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
||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 per inspection cycle
||$26,562.50 per inspection cycle
|Inspect the stabilator tip ribs.
||0.5 work-hour x $85 per hour
|Replace the stabilator tab forward
||4 work-hours x $85 per hour =
|Install additional nose ribs.
||1 work-hour x $85 per hour =
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:
||Cost per product
|Repair stabilator tip tube and
weight assemblies (airplanes without kit P/N 763 987).
||4 work-hours x $85 per hour =
|Install missing stabilator tip
rib rivets and/or the stabilator tip tube and weight assembly attachment
||1 work hour x $85 per hour =
||5 work-hours x $85 per hour =
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.
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
For the reasons discussed above, I certify this proposed
(1) Is not a "significant regulatory action" under Executive
(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
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: