The test aircraft was a medium-range model for about 70 passengers. For flights, a CFRP component about 5 x 3 meters long was used. (©Photo Alenia Aermacchi)
Scientists have conducted flights using a measurement configuration based on fiber optics to accurately verify the degree to which carbon fiber reinforced plastic (CFRP) parts deform during flight. With the help of fiber optic technology, optical measuring fibers detected even minimal deformations, which is not possible with conventional metallic strain gauges.

The aim of the measurement flights was to obtain solid data that can be compared with the theoretical calculations of the flight behavior of CFRP. The real data require aircraft manufacturers to build components so precisely that they can withstand the stresses that occur in the respective aircraft model. This has so far only been possible by approximation.

It is also possible with this system to monitor the structure for its condition during the flight. A change in the deformation behavior might indicate damage. With such a monitoring of the structure, components could remain in use much longer.

Source