Window inspection prisms are primarily used by shops and owners of pressured aircraft to look inside window panes and examine for cracks around the mounting holes.
Naturally, these prisms must be perfectly transparent so that examiners have a clear view when performing inspections. However, prisms get scratched over time and need to be polished to remove any damage and regain their transparency. Such care is not only a cost-effective means of prolonging a prism’s life, but it’s a big plus for safety as well.
Aircraft Window Repair (AWR) believes that many of the prisms currently in use are in desperate need of polishing.