Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
AIR-22-13
May 27, 2022
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin alerts owners,
operators, maintenance technicians, and inspectors of an airworthiness
concern on Sierra Hotel Aero, Inc. (type certificate formerly held by
Ryan) Model Navion (L-17A), Navion A (L-17B, L-17C), Navion B, Navion
D, Navion E, Navion F, Navion G, and Navion H airplanes, specifically
the importance of thoroughly inspecting the main landing gear (MLG)
components during maintenance inspections.
At this time, the airworthiness concern is not an unsafe condition that
would warrant airworthiness directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) part 39.
Background
The FAA received a report of the MLG failing during the landing and
taxi of a Model Navion B airplane. The pilot reported a "snap" noise
during a "smooth and normal" landing on a dry concrete runway. The
airplane taxied the entire length of the runway for the rollout until
it became difficult to taxi the airplane straight. Upon exiting the
aircraft, the pilot identified a failure of the left MLG.
Investigations determined that the left main gear retraction link (part
number (P/N) 143-33165-20) developed a fatigue failure of the weld
joint of the brace middle tube to clevis-shaped fork, causing the
displacement of the left MLG strut outboard to the wingtip and
consequent substantial damage to the underside of the left wing.
The main gear retraction links, Navion P/N 143-33165-20, was one of the
replacement options required by AD 63-21-05, effective November 1,
1963. This AD was issued to replace Navion P/N 143-33165-10 main gear
retraction links with revised assembly Navion P/N 143-33165-20, Temco
P/N 57001-9, or FAA-approved equivalent having the longer lap welded
center section that completely covers the turned down part of the end
fitting.
Recommendations
During each annual or
100-hour inspection, inspect the MLG in accordance with the latest
revision of the applicable service or maintenance manual to ensure a
thorough inspection for any developing cracks in the MLG structure,
particularly the welded joints of the upper side brace assembly.
Report inspection findings
or cracks of the MLG weld joint to the FAA contact below. Reporting is
voluntary. The FAA will analyze the inspection result information
received to determine further action. Include the specific airplane
model, airplane serial number, MLG part number, and hours
time-in-service on the airplane and the affected MLG. As part of its
commitment to continued operational safety, the FAA is monitoring the
Navion airplanes for issues related to landing gear weld joint fatigue
cracks and requests submission of such reports to the person listed
under For Further Information Contact.
Paperwork Reduction Act Statement
A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0731. Public
reporting for this collection of information is estimated to be
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, completing and reviewing the collection of
information. All responses to this collection of information are
voluntary; the nature and extent of confidentiality to be provided, if
any. Send comments regarding this burden estimate or any other aspect
of this collection of information, including suggestions for reducing
this burden to: Information Collection Clearance Officer, FAA, 10101
Hillwood Parkway, Fort Worth, TX 76177-1524.
For Further Information Contact
Steven Rosenfeld, Aviation Safety Engineer and Program Manager, Chicago
ACO Branch, FAA, 2300 E. Devon Avenue, Des Plaines, IL 60018; phone:
(847) 294-7030; email: steven.rosenfeld@faa.gov.
For Related Service Information Contact
Sierra Hotel Aero, Inc., 1690 Aeronca Lane, Fleming Field KSGS, South
St. Paul, MN 55075; phone: (651) 306-1456; email: chris@navion.com.