Lightning Test Standards for Aircraft

Modern aircrafts are highly vulnerable to lightning. Since safety is of paramount importance to the aircraft, the scope, levels and duration of many of the test requirements is far higher than would be expected for ground based equipment, not withstanding the unique environment itself.

The major challenge of the aircraft industry is making lighter products that give higher performance than the existing technology thereby reducing the environmental impact on the planet. This goal is a massive undertaking since many of the composite materials that are now being introduced do not offer the same level of protection that aluminium products offer.

In addition to the use of composite materials in aircraft, there is an increasing need to reduce the amount of wire within the airframe (less wire, less weight and hence less fuel). This is achieved with multiplexed signals however as more product is designed to be 'fly by wire' this also creates many additional issues that have to be taken into account during the qualification phase.

The effects of lightning on aircraft are broadly classified into direct and indirect effects.  The direct effects are the physical damage caused by the lightning strike whilst the aircraft is in the air or on the ground.  These include tufting of non-metallic composites, splintering/shattering, fuel ignition, puncture of electrical insulation, etc.  The indirect effects are those caused by the electric and/or magnetic fields of lightning.  They include temporary upset/malfunction and/or permanent damage to the various electronic/electric circuits.

Standardisation of test methods means that aircraft subsystems can be designed, manufactured and tested at any location around the world.  Lightning testing for civilian aircraft and systems use the RTCA DO-160 standard which is ideally suited to fulfill the standardisation role and is used as the basis for airworthiness certification.

DO-160 deals with requirements for equipment level tests using indirect lightning effects and direct lightning strikes on airframes. Testing of this type represents the real event.

There are many standards in use at national level in the field of military aviation, including DEF STAN 59-411 in the UK. There are no global standards covering military testing although the STANAG/AECTP documents provide a degree of integration amongst NATO member states. 

An aircraft should be lightning proofed, TRaC services can help you comply with a range of standards and guide you through the rigorous process and requirements of the aerospace market.