Researchers at the Sandia National Laboratory in Albuquerque, N.M., say networks of sensors mounted on commercial aircraft might one day continually check for the formation of structural defects, and could reduce or eliminate scheduled aircraft inspections. And, researchers say, the applications could go beyond structural elements to include avionics, electronics, hydraulics and other systems. “With sensors continually checking for the first signs of wear and tear, you can restrict your maintenance efforts to when you need human intervention,” said Dennis Roach, who leads the Sandia team evaluating some of the first sensor systems for aircraft. Structural health monitoring (SHM), Roach said, could significantly reduce maintenance and repair expenses for commercial aircraft, now estimated at about a quarter of the fleet’s operating costs. “There is recognition that SHM’s time has come, an opinion you would not have heard from many people a few years ago,” says Roach. The SHM sensors being developed or evaluated at Sandia can find fatigue damage, hidden cracks in hard-to-reach locations, disbonded joints, erosion, impact damage and corrosion. Ground crew technicians might plug a laptop or diagnostic station into a central port on the aircraft to download structural health data. Eventually “smart structures” fitted with many sensors could self-diagnose and signal an operator when repairs are needed.