DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0574; Product Identifier 2019-CE-015-AD; Amendment
39-21340; AD 2020-24-10]
Airworthiness Directives; Aerostar Aircraft Corporation Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
Aerostar Aircraft Corporation (Aerostar) Model PA-60-601P (Aerostar
601P), PA-60-602P (Aerostar 602P), and PA-60-700P (Aerostar 700P)
airplanes. This AD was prompted by reports of corrosion on the elevator
and aileron balance tubes. This AD requires repetitively inspecting the
elevator and aileron balance tubes for corrosion and rust and replacing
the tube. The FAA is issuing this AD to address the unsafe condition on
DATES: This AD is effective January 22, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 22,
ADDRESSES: For service information identified in this final rule,
contact Aerostar Aircraft Corporation, 2265 West Aerostar Way, Hayden
Lake, ID 83835; telephone: (208) 762-0338; fax: (208) 762-8349;
internet: https://aerostaraircraft.com. You may review this referenced
service information at the FAA, Airworthiness Products Section,
Operational Safety Branch, 901 Locust, Kansas City, Missouri 64106. For
information on the availability of this material at the FAA, call (816)
329-4148. It is also available on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-0574.
Examining the AD Docket
You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-
0574; 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, 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.
FOR FURTHER INFORMATION CONTACT: David Herron, Aerospace Engineer,
Seattle ACO Branch, FAA, 2200 S 216th St., Des Moines, WA 98198; phone:
(206) 231-3544; email: email@example.com.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all Aerostar Model PA-
60-601P (Aerostar 601P), PA-60-602P (Aerostar 602P), and PA-60-700P
(Aerostar 700P) airplanes. The NPRM published in the Federal Register
on June 26, 2020 (85 FR 38338). The NPRM was prompted by reports of
corrosion on the elevator and aileron balance tubes, which may be
hidden by rubber boots. In the NPRM, the FAA proposed to require
repetitively inspecting the elevator and aileron balance tubes for
corrosion (pitting and flaking) and rust (discoloration) and replacing
The FAA is issuing this AD to detect corrosion on the elevator and
aileron balance tubes. The unsafe condition, if not addressed, could
result in failure of the aileron and elevator balance tubes, jamming of
the aileron and/or elevator balance tubes, and loss of control of the
The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received comments from three
commenters. The commenters were Yankee Aviation Services, Inc. and two
individuals. The following presents the comments received on the NPRM
and the FAA's response to each comment.
Request To Withdraw NPRM
An individual commenter requested that the NPRM be withdrawn. The
commenter stated there is insufficient data supporting the unsafe
condition and questioned the motive for the proposed AD, as Aerostar
would benefit financially from the sale of parts needed to comply with
the proposed requirements. The commenter observed that Aerostar's
service information did not provide details concerning the number,
source, or content of the reported events of corrosion and the degree
to which the unsafe condition is present in the fleet of Aerostar
airplanes. The commenter further stated that the service information
and the traditional diligence of the Aerostar owner community are
sufficient to address the unsafe condition.
The FAA disagrees. The FAA issues an AD after finding that an
unsafe condition exists or is likely to develop in aircraft of a
particular type design. For this AD, the FAA reviewed the reports
received from Aerostar and the effects that failure of these tubes
could have on an airplane. Aerostar initially discovered corrosion on
the elevator and aileron balance tubes while conducting maintenance on
an airplane. This discovery prompted Aerostar to inspect the other four
airplanes in its facility, which resulted in the identification of
three additional incidents of corrosion on elevator and aileron balance
tubes. The FAA's analysis of this data determined an unsafe condition
exists and warrants corrective action through an AD. To the extent
Aerostar has issued service information on this issue, while an
operator may incorporate into its maintenance program the inspections
in the manufacturer's service bulletin, not all operators are required
to do so. In order for these inspections to become mandatory, and to
correct the unsafe condition identified in the NPRM, the FAA must issue
The FAA did not change this AD based on this comment.
Request To Remove Requirement To Replace All Tubes
All three commenters requested that the FAA remove the proposed
requirement to replace the elevator and aileron balance tubes even if
no corrosion and rust is found during the inspection. Two commenters
noted that requiring the replacement of parts found to be airworthy
does not promote safety and instead subjects owners to unnecessary
expenses. Yankee Aviation Services, Inc., stated the new tubes are the
same as those being replaced and do not have corrosion proofing.
The FAA disagrees. The FAA determined that the root cause of the
rust and corrosion on the elevator and aileron balance tubes is likely
a deficient corrosion protection specification in the initial design
and manufacture of these tubes. The commenter is not correct that the
new tubes are the same as those being replaced. The existing balance
tubes are part number (P/N) 26003-003, Revision L or earlier, while the
new replacement balance tubes are P/N 26003-003, Revision M or later,
as specified in the service information. The Revision M and later
balance tubes have been manufactured with corrosion protection (Zinc
Chromate primer) that was not applied on the earlier versions of the
tubes. The FAA did not change this AD based on these comments.
Request To Allow Part Repair Instead of Replacement
Yankee Aviation Services, Inc., requested the FAA revise the
proposed AD to allow the repair of tubes with rust instead of
replacement. The commenter stated that a tube with light rust and a
wall thickness of 0.049 inch could be repaired by being wire brushed
and painted with an epoxy paint.
The FAA disagrees. Repairing the tubes without replacement would
not address the root cause of the rust and
corrosion, which the FAA determined is likely a deficient corrosion
protection specification in the initial design and manufacture of these
tubes. The Revision M or later balance tubes have been manufactured
with corrosion protection (Zinc Chromate primer) that was not applied
on the earlier versions of the tubes. The commenter's request would
allow the tubes to remain installed on the airplane without this
additional corrosion protection. The FAA did not change this AD based
on this comment.
The FAA reviewed the relevant data, considered the comments
received, and determined that air safety and the public interest
require adopting this AD as proposed. Accordingly, the FAA is issuing
this AD to address the unsafe condition on these products.
Related Service Information Under 1 CFR part 51
The FAA reviewed Aerostar Service Bulletin SB600-138, dated August
30, 2018. The service bulletin contains procedures for repetitively
inspecting the elevator and aileron balance tubes for corrosion
(pitting and flaking) and rust (discoloration) and replacing the tubes
at a specified time and repetitively if necessary. 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.
Differences Between This AD and the Service Information
This AD does not require completing the reply card and returning it
to Aerostar as specified in Step 13 of Part II of the service
Costs of Compliance
The FAA estimates that this AD affects 404 airplanes of U.S.
The FAA estimates the following costs to comply with this AD:
||Cost per product
||Cost on U.S. operators
|Inspect elevator and aileron
||1 work-hour x $85 per hour =
$85 per inspection cycle
||$85 per inspection
||$34,340 per inspection
|Replace elevator and aileron
||8 work-hours x $85 per hour =
The FAA estimates the following costs
to do any necessary
replacements that are required based on the results of the repetitive
inspections, assuming separate replacement intervals. The FAA has no
way of determining the number of airplanes that might need these
|Replace elevator balance tube
||8 work-hours x $85 per hour =
|Replace aileron balance tube
||8 work-hours x $85 per hour =
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.
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
(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
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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