Eddy current testing to detect cracks and corrosion in the P-3C Orion vertical stabilizer spar caps

The US Navy's Sustained Readiness Program (SRP) provides a cost effective a lternative in maintaining the existing P-3C inventory and avoiding the forc ed retirement of valuable fleet assets. The rapidly deteriorating material condition of the aging aircraft is the most significant factor limiting air craft operational service life and thus decreasing the life of the airframe . Nondestructive testing (NDT) is an essential step in this overhaul activi ty. A rapid and accurate eddy current test that detects cracks and corrosio n in the multiple layered vertical stabilizer spar cap structures of the P- 3C Orion aircraft has been developed. This paper describes the development of a spot probe eddy current technique designed for detection of both crack s and corrosion in second layered structures. This technique minimizes inst rument calibration and also simplifies reference standard design.