Clearing Aircraft against Induced Lightning Transients

This paper describes the latest ideas on a modified process and methods for the clearance of aircraft to the lightning external environment. It covers the whole sequence from the specification of equipment qualification requirements to the demonstration that these are within the electromagnetic environment in which the equipment is installed in the event of strikes up to the severity of the internationally agreed full-threat level. In particular, the process includes computational modelling and whole aircraft/system testing as standard tools, requiring additional levels of confidence where either one is not available or un-feasible. It also contains methods proposed to improve the integrity of whole aircraft testing; an essential concomitant of the availability of computational techniques and the need to validate them. The reasons for changes to currently accepted practice will be explained and justified. The paper will go on to explain how the three resulting sets of data, from equipment qualification tests, computational analysis and whole aircraft/system tests, should be used to recommend lightning airworthiness clearance.