Analysing failed fibre composite aircraft structures will be a significant challenge for regulators investigating the causes of aircraft accidents in the future, according to the Australian Transport Safety Bureau.

Fibre composite structures also present new safety challenges to investigators and those responding to and witnessing aircraft accidents, the bureau says in a new report on the capability and safety of fibre composite aircraft.

Aviation regulators should consider making the provision of education programmes on composite materials a higher priority than they are currently due to the significant increase of the use of fibre composite materials in aircraft structures and the amount of conflicting and incorrect information about the safety and capability of the materials, says the bureau.

Education programmes should focus on safe material handling, correct repair procedures for damaged composite structures and techniques for conducting non-destructive inspection and detection of subsurface damage, it adds.

There are almost 2,000 aircraft on the Australian civil register alone that are made of or contain fibre composite materials, says the ATSB.

These include most of the mainline jet fleet, many popular general aviation aircraft and a third of the growing amateur-built aircraft fleet.

While there is a wealth of knowledge about the load capabilities, damage tolerance and repairability of metal aircraft structures, there is much less known about how fibre composites behave under impact loads, how to identify failure modes and what safety precautions must be taken by accident investigators, says the ATSB.

And while regulators are experienced at identifying signs and causes of failure in traditional aircraft structures made from metal, fibre composites fail in different and unusual ways that are still not fully understood, it adds.

The safety challenges of fibre composites in aircraft accidents also need to be understood, says the bureau.

Composite structures that shatter on impact produce needle-sharp airborne fibres that can cause skin and eye irritation inhaled glass dust can cause pulmonary fibrosis and other asbestos-related diseases and smoke and toxic gases from composites cause further health risks.

The ATSB advises that emergency services review their aircraft accident response procedures to incorporate composite-specific risks.

  • Accidents and Incidents 2007

Source: Flight International