Abstract
Throughout its service life an aircraft is subjected to varying loads. Because of those periodically appearing stresses, undesirable and irreversible changes in structure may occur. As a consequence, cracks are formed, which reduce aircraft structural strength, significantly affecting structural integrity. For that reason, intensive research works are carried out around the world to develop innovative and reliable methods for detection of cracks initiation and propagation. This paper presents two methods of crack detection. One of them uses wireless polymer gages for determining deformation in a test region. The other one uses electrical, resistive ladder sensors for detection of cracks and their length determination.