<title>NDI of aircraft fuselage structures using the Dripless Bubbler ultrasonic scanner</title>

Abstract

A need exists in airline maintenance for a method of producing high quality, easily interpreted images that provides details on the soundness of aircraft fuselage structures. The 'dripless bubbler' technique combines the use of broadband focused-beam ultrasonic immersion transducers with a method of maintaining a contained, bubble-free water pool. The use of the dripless bubbler, when combined with a portable robotic scanner and data acquisition system, produces ultrasonic C-scan and B-scan images for evaluating the extent of corrosion within lap and butt joints and ont he interior of fuselage skins. Also easily identifiable are disbonds in the skin-to-structure adhesive joints and delamination type defects in composite structures. The high image quality is not affected when scanning over surface irregularities; the dripless bubbler can be scanned over button-head rivets and lap splices with minimal change in transducer orientation and no loss of couplant.