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Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraftThis paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft's right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in- flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft's right main wheel fairing. Inspection results and techniques developed to verify the aircraft's structural integrity are discussed.
Document ID
19990026392
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Moore, D. G.
(Department of Energy Washington, DC United States)
Jones, C. R.
(Department of Energy Washington, DC United States)
Mihelic, J. E.
(Department of Energy Washington, DC United States)
Barnes, J. D.
(Department of Energy Washington, DC United States)
Date Acquired
August 19, 2013
Publication Date
December 31, 1998
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
CONF-980830
DE98-006173
SAND-98-0248C
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
US COAST GUARD
AIRCRAFT

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