An aircraft windshield's sealant system is the most critical element in extending windshield service life. The outboard moisture, or weather, seal protects against moisture ingress, which can cause delamination, interlayer degradation and windshield heating system damage. Commonly called a hump seal because of its appearance, this seal also acts as an aerodynamic smoother and covers the outboard edge of the transparency. Because it is subjected to the effects of wind and rain erosion and UV exposure, a hump seal can degrade over time. It is important to maintain the seal.
PPG Aerospace - Transparencies makes it easy to repair a hump seal in the field with hump seal repair kits designed for windshields on commercial and general aviation aircraft. The kits contain everything needed to repair a hump seal on a windshield, including a new PR-1425CF chromate-free sealant by PPG Aerospace. Because PR-1425CF sealant cures in less than half the time of PR-1425 sealant, hump seal repairs can be done overnight on the line or during a minor maintenance check in the hangar. Contact the nearest PPG Aerospace application support center for more information and to purchase hump seal repairs kits.
Hump seal repair procedures for most windshields are outlined in the applicable Aircraft Maintenance Manual (AAM) or PPG Abbreviated Component Maintenance Manual. (ACMM). PPG recommends inspecting the windshield moisture seal every four months or every 1,000 flight hours, whichever occurs first, for signs of erosion, degradation or cracking. |