Which of these methods may be used to inspect fiberglass/honeycomb structures for entrapped water? 1. Acoustic emission monitoring. 2. X-ray. 3. Backlighting.

X-ray and Backlighting

Explanation:

Fiberglass/honeycomb structures can be possibly inspected for entrapped water either by Backlighting or X-ray method.

The Backlighting method of inspection is carried out by removing all the surface paints and beaming a strong light on just one side of the panel whilst examining from the other side for any dark areas that would give an indication of entrapped water.