A water sensitivity gauge for neutron radiology of CF188 flight control surfaces

Water ingress into CF 188 Hornet aircraft flight control surfaces (FCS) is currently under investigation and monitoring. This water ingress is causing adhesive hydration and water entrapment within the honeycomb composite structure. Neutron radiography and radioscopy using the neutron radiology system (NRS) on the SLOWPOKE-2 Facility at Royal Military College (RMC) are able to detect water within these components. However, a means of quantifying the amount of water trapped inside each honeycomb cell using the digital camera image has not been developed. With the ability to analyze the digital image with image processing software and to compare intensity values of materials, it was feasible to develop a gauge made of a solid material that could be used to determine the amount of water in the FCS panels.; An intensive study was conducted to determine the range of linear correlation between water and the gauge material using the NRS at RMC. The uniformity of the image, effects of different imaging configurations, and the potential for a linear correlation between water and high density polyethylene (HDPE) were examined. Image processing was investigated to determine if this could be used to reduce the non-uniform illumination of the image. Once a correlation between water and HDPE was found, this was compared using film and a second scintillation screen at RMC, and the neutron radioscopy system at the Pennsylvania State University's Breazeale Reactor.; Analysis showed that a HDPE gauge could be used to estimate the height of water within a composite flight control surface to within a range of four millimetres (mm). The lower and upper limit of this relationship for water was 0.67 mm and 10 mm, respectively. For HDPE, the ranges of height are from 0 to 5 mm. This gauge was shown to be able to predict accurately the height of water 70% of the time using a pseudocolouring technique on the image.