Aircraft windows, especially the windshield, require maintenance just as the windows and windshields in any vehicle do. The pilot must have a clear, unobstructed view through the windshield to monitor conditions on the horizon and avoid debris that could potentially damage aircraft windows and the rest of the plane.
Most aircraft windows are made of acrylic plastic which can be easily scratched in flight and during cleaning. Therefore, use extreme care during the cleaning process. Begin by flushing window’s surface with water, allowing accumulated debris to soak so that it loosens and removes easily. A small amount of dish washing liquid can aid in loosening bug residue and dirt. Once the larger debris has been removed, rinse the window with clear water, and then dry with a clean, soft cloth. Once the windshield is dry, choose a cleaner or polish recommended for acrylic windows and wipe following the manufacturer’s recommendations. Avoid using traditional glass cleaners that contain ammonia, because those products can cause crazing or microscopic cracks in acrylic windows. Some maintenance crews use furniture polish on airplane windows, but these products can cause build-up and are not much less expensive than window cleaner products designed specifically for aircraft windows.
Common Windshield Problems
Several common problems occur in airplane windshields that require maintenance. These include:
- In-flight cracking – In-flight cracking often occurs when moisture penetrates the aerodynamic seal, causing heat-coating problems that lead to cracking of the outer ply of the window. Because exposure to wind and rain can compromise the aerodynamic seals, frequent inspections can help pilots avoid in-flight cracking of aircraft windows and windshields.
- Cloudy areas, burn marks or bubbles – Cloudy areas in the upper corner of a window could indicate moisture ingress. Burn marks, bubbles or moisture stains indicate a window that will soon be unserviceable and should be replaced.
Routine Maintenance Guidelines
Most airplane manufacturers provide guidelines for scheduled maintenance of aircraft windows. Normally, these include frequent visual inspections that could determine if windows need replacing or repairing. Power connectors should be tight and sealed properly. Any service bulletins or letters sent by manufacturers should be read thoroughly, as they often indicate specific problems in certain models that need to be addressed. Any unserviceable windshields should be replaced with windows of improved design.