Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NM-08-28
June 12, 2008
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) advises you,
owners and operators of all McDonnell Douglas Corporation Model
DC3-G102, DC3-G102A (Army C-49E, C-50, C-50A, C-50B, C-50C, C-50D,
C-51), DC3-G103A, DC3-G202A (Army C-49, C-49A, C-49B, C-49C, C-49D,
C-49J, C-49K; Navy R4D-2), DC3A-SCG, DC3A-SC3G, DC3A-S1CG, DC3A-S1C3G
(Army C-41, C-41A, C-48, C-48A, C-52, C-52A, C-52B, C-52C, C-53, C-53B,
C-53C, C-53D, C-68; Navy R4D-3, R4D-4), DC3A-S4C4G, DC3C-SC3G,
DC3C-S1C3G, -S4C4G (Army C-47, C-47A; Navy R4D-1, R4D-5),
DC3C-R-1830-90C (Army C-47B, Navy R4D-6), DC3D-R-1830-90C (Army C-117A)
airplanes, to inspect for cracks initiating from the fairing attachment
holes in the tail wheel fork.
Background
On February 25, 2008, we received a report indicating that a Model
DC-3C (produced as a C-47A) airplane experienced failure of the tail
wheel fork during rollout after landing. The airplane suffered
structural damage to the bottom of the fuselage immediately adjacent to
the tail wheel area. Subsequent inspection revealed that the tail wheel
fork, part number 5115862, had failed. Review of the failed part
indicated that a crack had initiated at a threaded fastener hole for
the tail wheel strut fairing. Discoloration in the vicinity of the
failure suggested the crack was present for some time. In this case,
the fairing was not installed but the two attachment screws were in
place. The airplane had accumulated 19,482 total flight hours.
Currently, there is no specific inspection requirement of the tail
wheel area.
Recommendations
Although none have been reported, failure of the tail wheel fork in
flight could result in loss of the tail wheel. To minimize the
possibility of fatigue crack initiation and propagation to failure of
the fork, we recommend the following be accomplished:
Perform visual inspections
of the fairing attach screw hole areas of the tail wheel fork for
cracks (under proper lighting, with a 10X-20X magnifying glass, with
the fairing and screws removed, and the area properly cleaned); and
Assure that appropriate screws are
installed in the fairing attach screw holes before returning the
airplane to service following the crack inspection.
Note that the inspection may be
accomplished during other maintenance activities, such as a scheduled
lubrication of the tail wheel fork bearings. We also recommend that the
inspection be repeated on an annual basis, which can greatly reduce
downtime and cost of repair due to collateral damage from a fatigue
failure.
For Further Information Contact
David Y. J. Hsu, Aerospace Engineer
Los Angeles Aircraft Certification Office, ANM-120L
3960 Paramount Blvd., Lakewood, CA 90712
Telephone: (562) 627-5323; fax: (562) 627-5210; Email: david.hsu@faa.gov