28 September 1994 LANTIRN infrared window failure analysis
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Abstract
Analysis of 68 condemned LANTIRN navigation pod FLIR windows was undertaken to determine the nature and extent of damage to these windows. Visual and low-magnification examinations using reflected and transmitted light conditions were performed, as well as profilometry and scanning electron microscopy (SEM) examination on selected specimens. A number of primary modes were found which accounted for the majority of the failures seen in this population of windows. These modes were: high energy impacts due to large objects such as hail, birds, and runway debris; interaction of the residual stress state at the interface of the bulk ZnSe/ZnS coating with rain and bug strikes; and opacification due to sand erosion and atmospheric etching. Machining damage and misoriented window installation were also found. Windows which had seen appreciable hours of service were almost completely devoid of AR coating on the forward face. A navigation pod, which houses the window, was also obtained to determine if the window installation contributed to the causes of failure. Suggestions to improve the reliability of the present window material were listed.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nora R. Osborne, George A. Graves, Kristen Alexander, Deborah A. Simerlink, Raymond Haren, "LANTIRN infrared window failure analysis", Proc. SPIE 2286, Window and Dome Technologies and Materials IV, (28 September 1994); doi: 10.1117/12.187365; https://doi.org/10.1117/12.187365
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