Aircraft Cockpit Window Improvements Enabled by High-Strength Tempered Glass

Abstract

<div>This research was initiated with the goal of developing a significantly stronger aircraft transparency design that would reduce transparency failures from bird strikes. The objective of this research is to demonstrate the fact that incorporating high-strength tempered glass into cockpit window constructions for commercial aircraft can produce enhanced safety protection from bird strikes and weight savings. Thermal glass tempering technology was developed that advances the state of the art for high-strength tempered glass, producing 28 to 36% higher tempered strength.</div> <div>As part of this research, glass probability of failure prediction methodology was introduced for determining the performance of transparencies from simulated bird impact loading. Data used in the failure calculation include the total performance strength of highly tempered glass derived from the basic strength of the glass, the temper level, the time duration of the load, and the area under load.</div> <div>A high-strength transparency construction developed using advanced technology tempered glass could produce significant weight saving estimated at 28% for a typical Boeing 737 jetliner window, or about 11.5 kg for the four windows of the Boeing 737 flight deck.</div> <div>The conclusions from the principals developed in this research for an advanced transparency construction including a 0.378-in. thick high-strength core ply could reduce the probability of failure from bird strike loading from 4,503 to 953 parts-per-million (PPM). A 0.500-in. thick high-strength standard thickness core ply could reduce the probability of failure from bird strike loading from 4,503 to 1.7 PPM.</div>