A Beyond Economical Repair, BER, window is the most troubling aspect in the world of window repair. The common pitfalls are delamination, buss bar failure, followed by corrosion. With respect to delamination it is the most obvious mechanism and the easiest to see immediately. Often times they may be minor and within an acceptable range to continue service. The cause of a delamination is moisture between the layers of glass. Once a window is removed from an aircraft and sits in a high moisture environment the accumulated moisture begins to expand. It commonly look foggy around the edge of the transparency and once the width is about 2 inches the entire transparency must be replaced and it would be cost effective to purchase a new or serviceable window.
Buss bar failures are the next worry with a window, as this permits the window to defog and maintain visibility. If the resistance is not in the proper range obviously it will function appropriately. This is determined once a window reaches the repair facility and theoretically it can be done at the teardown location however few companies have the manuals noting the proper functioning ranges, so they could not tell you before hand if the buss bar is operating properly. This failure is caused by moisture also, as is well known circuitry is not friendly with moisture. It can also be caused by improper removal or mishandling of the unit, so be careful and store the removed window in a temperature and humidity controlled storage environment.
Corrosion is the most difficult failure mechanism to determine, since it can be covered by dirt and grease atop the window or is hidden within the moving parts or inside of the assembly. It is best determined in the shop as this is a clean environment with appropriate solvents to remove the coverings without damaging the part. Inner granular corrosion or pitting of the window frame is worry. Once this pitting reaches a particular depth or depending on the location it can not be sanded or polished out without compromising the integrity of the structure itself.
So, to find out about whether your window is repairable click our logo below to receive a quote on potential repair cost and then send in your windows for evaluation. There is no cost to our customers to evaluate your window and receive the most cost effective services for your window and other aircraft components.