Aircraft damage detection goes hi-tech

By Leon Engelbrecht, ITWeb senior writer

Johannesburg, 14 Sept 2007

BAE Systems has demonstrated an integrated real-time automated damage detection system on a Hawk fighter jet that may be fitted to the SA Air Force fleet. SA operates 24 Hawks in the advanced training role.

The British defence company says the system consists of a constellation of smart sensors that can automatically inspect structures for damage. It will potentially save the aviation industry and air forces millions in servicing and support costs, BAE claims.

The company says the flight trial is an important step towards the eventual goal of self-inspecting aircraft. The technology, dubbed the Advanced Structural Health Monitoring System (AHMOS), is being developed as part of a European Research and Development funded initiative.

Jim McFeat, AHMOS technical manager at BAE Systems, says structural inspection is a significant factor in the cost of supporting fleets of both military and commercial aircraft.

Most aircraft now fly for at least 40 years and, as the aircraft age, the servicing needed to maintain stringent air-worthiness standards becomes ever more costly. "The new system aims to avoid lengthy and expensive structural inspections that require the repeated dismantling of large sections of aircraft," says McFeat. "Very often such inspections are precautionary and no faults that need repairing are found."

During flight testing, the "acoustic emission detection" kit housed in a self-contained pod attached to the underside of the Hawk was able to pinpoint cracks in specifically designed dummy structures and download a diagnosis when the aircraft landed.

Good results

"Using a combination of strain gauge sensors and fibre optic cables connected to a computer, and contained within an aerodynamic pod under the fuselage of the Hawk, we have now demonstrated the technology works," McFeat says.

"We have been able to compare all of the aircraft's manoeuvres in flight with the pilot's notes and our own computer, and in the two flights so far undertaken, we have had good results. We have three other flights planned before we issue our formal report in early 2008.

"Ultimately, we are trying to automate the non-destructive testing process in the same way that car manufacturers have done for engine management systems. The customer will plug a computer into a data-box on the aircraft and download in-flight information gathered from gauges and sensors at strategic points."

If sensors fitted deep inside the aircraft structure can reliably detect the onset of damage, the need to dismantle sections of the airframe will be considerably reduced. The new detection process can be performed remotely, at the press of a button or automatically online. It is estimated that this could save many millions of pounds over the lifetime of a fleet.

"Engineers are just beginning to realise the potential value of this type of structural monitoring."