DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0833; Product Identifier 2018-CE-031-AD; Amendment
39-21121; AD 2020-10-03]
RIN 2120-AA64

Airworthiness Directives; Weatherly Aircraft Company

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Weatherly Aircraft Company (Weatherly) Models 201, 201A, 201B, 201C,
620, 620A, 620B, 620B-TG, and 620TP airplanes. This AD was prompted by
reports of fatigue cracking of the center wing and outer wing spar
hinge brackets due to corrosion pitting. This AD requires repetitive
inspections of the wing hinge brackets, pins, and wing spar structure
with repair or replacement of parts as necessary. The FAA is issuing
this AD to address the unsafe condition on these products.

DATES: This AD is effective June 15, 2020.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of June 15,
2020.

ADDRESSES: For service information identified in this final rule,
contact Weatherly Aircraft Company, 2034 West Potomac Avenue, Chicago,
Illinois 60622-3152; telephone: (424) 772-1812; email:
garybeck@cox.net. You may view this 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-2018-0833.

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-2018-
0833; 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, the regulatory evaluation, 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: Roger Durbin, Senior Engineer,
Airframe Section, Los Angeles Aircraft Certification Office, FAA, 3960
Paramount Blvd, Suite 100, Lakewood, California, 90712; phone: (562)
627-5233; fax: (562) 627-5210; email: roger.durbin@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to Weatherly Models 201,
201A, 201B, 201C, 620, 620A, 620B, 620B-TG, and 620TP airplanes. The
NPRM published in the Federal Register on September 18, 2018 (83 FR
47116). The NPRM was prompted by notification the FAA received in 2015 of a
fatal accident caused by the in-flight structural failure of a wing on a
Weatherly Model 620B airplane. The accident investigation found
multiple fatigue cracks in the center wing front spar lower hinge
bracket. As a result of operator inspections, a cracked hinge bracket
in the center wing to outer wing joint was also reported on a different
airplane. The hinge bracket from the second report had completely
failed, and the airplane was relying on the second failsafe hinge
bracket to carry the wing loads.
To correct this unsafe condition, the FAA issued AD 2016-07-11 (81
FR 18461, March 31, 2016) (``AD 2016-07-11''), which requires a one-
time visual inspection of the center and outer wing front spar lower
hinge brackets for cracks and corrosion and corrective action as
necessary. AD 2016-07-11 also requires sending a report of the
inspection results to the FAA.
Since the FAA issued AD 2016-07-11, Weatherly has issued new
service information for repetitive visual and detailed inspections.
Since the cause of the fatigue cracks were attributed to corrosion pits
on the accident airplane, the NPRM proposed to require those repetitive
visual and detailed inspection actions. The FAA is issuing this AD to
address the unsafe condition on these products.
The NPRM incorrectly stated that Weatherly had developed improved
center wing hinge brackets manufactured from corrosion resistant
material. The FAA has learned that those improved brackets were not
developed or approved. Therefore, improved brackets are not currently
available to correct the unsafe condition.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The following presents the comments
received on the NPRM and the FAA's response to each comment.

Request To Extend the Inspection Intervals

Two individuals requested that the FAA allow more than 5 years for
the follow-up detailed inspection requirement. One commenter stated
that removing all fittings and hardware every five years is unnecessary
if corrosion preventative measures are taken during the initial
detailed inspection. The commenter stated that, for aircraft that are
20-30 years old, if no unacceptable corrosion is found and the aircraft
is reassembled with corrosion preventative measures, the detailed
inspection/disassembly intervals should be extended to 15 or more
years. The other commenter requested the FAA extend the requirement to
repeat the detailed inspection from 5 years to 10 years if an aircraft
owner proactively replaces the hinge brackets with Weatherly's improved
hinge brackets manufactured from corrosion resistant material. A third
commenter requested that the AD require a detailed visual inspection
within 50 hours of the effective date of the AD or within the next 6
months, whichever is sooner. According to the commenter, Weatherly's 3-
month compliance time did not seem well thought out. The commenter
further requested the AD allow installation of the Weatherly corrosion-
resistant hinge brackets as terminating action for the detailed
inspection requirements.
The FAA does not agree with the requests to change the inspection
intervals. The hinge brackets are close-tolerance parts that are
subject to wear, and neither testing nor analysis has substantiated
longer inspection intervals when corrosion inhibiting compounds are
used. In addition, as stated earlier, no improved hinge brackets with
corrosion resistant material are currently available; therefore,
extending the compliance time based on improved brackets is not
possible. In determining the inspection intervals, the FAA considered
that corrosion growth is highly variable and that the failed parts do
not represent average life times. No changes were made to the AD based
on these comments.

Request To Change the Inspection Requirements

One commenter requested the FAA reconsider the AD requirements
using the total time of the aircraft and the information in an AD
issued by the Australian Aviation Authority in 2002 regarding
retirement lives of the wing attachment fittings and lower spar cap.
The commenter did not identify the 2002 Australian AD by AD number.
However, the commenter did include a copy of Civil Aviation Safety
Authority AD/W620/2, Wing Hinge Pins, dated October 1996, which
requires a one-time inspection of the wing hinge pins for correct
length and installation.
The total aircraft time was not a factor in the proposed AD because
it is not a reliable predictor of fatigue crack initiation in the
presence of corrosion. The FAA has reviewed the 2002 Australian AD and
finds that it does not address any contributing factors associated with
the Weatherly Model 620B accident on August 26, 2015. No changes were
made to the AD based on this comment.

Conclusion

The FAA reviewed the relevant data, considered the comments
received, and determined that air safety and the public interest
require adopting this final rule as proposed except for minor editorial
changes. The FAA has determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Weatherly 201/620 Service Bulletin SB-201/620-
18001, Revision C, dated May 21, 2018. The service information
describes procedures for initial and repetitive inspections of the wing
hinge brackets, pins, and wing spar structure for corrosion and/or
cracks with repair or replacement as 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.

Costs of Compliance

The FAA estimates that this AD affects 94 airplanes of U.S.
registry.
The FAA estimates the following costs to comply with this AD:

Estimated Costs

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

On-Condition Costs

The on-condition costs reflects the cost to replace the entire
assembly. The scope of damage found in the required inspection and
which specific parts need replaced could vary significantly from
airplane to airplane. The FAA has no way of determining how much damage
may be found on each airplane or the cost to repair damaged parts on
each airplane or the number of airplanes that may require repair.

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

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
Order 12866,
(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
reference, Safety.

Adoption of the Amendment

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
directive (AD):