Need for new materials in aging aircraft structures

Post-Cold War political and economic considerations have resulted in effort s to extend the life of many aircraft that are the backbone of NATO operati onal forces. Although some are designated to be replaced with new aircraft, the replacement schedule for many often requires an unprecedented life spa n of up to 80 years before retirement. Aircraft within these older fleets h ave had, and continue to experience with growing frequency, fatigue and cor rosion related cracking problems that are of concern to operators. To susta in their airworthiness and reduce the maintenance burden, structural compon ents undergoing these aging problems will have to be repaired or replaced. Material development that has taken place since most of the older vintage m ilitary aircraft entered service has resulted in improved alloys and proces ses that can be used to upgrade life expectation, performance, and affordab ility of older systems. Some of these newer materials and the advantages th ey offer over their older counterparts are described.