Evolution of the lightning zoning guideline and coming challenges for lightning protections of unconventional platforms
Year: 2022
Type: conference-paper
Abstract: The lightning zoning is a cornerstone in the upstream lightning hazards analysis, in the purpose to define the threat at rotorcraft and at system levels, for both lightning direct and indirect effects. From 2014 to 2018, the regulatory working groups SAE-AE- 2 and EUROCAE WG31 have reviewed the lightning zoning document. A new issue was released (ED-91A or ARP5414B), as the result of the analysis of in-service experience (location and type of damage and failures), and leading to a better adaptation of the standard to the reality for the various types of aircraft including rotorcraft. This zoning of rotorcraft was a common work between five Helicopters manufacturers based on an initial proposal of Airbus. The main modification consists in the suppression of the lightning zone 2 (high probability of sweeping strike) of the airframe and of the zone 1 (high probability of attachment) on the nose. As the airframe is mainly in zone 3 (low probability of attachment), there is a need to consider the local effect of the protrusions (antennas, FLIR cameras...) on the zoning, and the possible creation of local zones 3 direct attachment (peak up to 40KA) or zone 1 (peak up to 200 KA). That work shows consequently the need to have a prediction tool to support the assessment of the local threat and in particular to evaluate the effect of protrusions on the attachment risk. It is mentioned in ED-91A/ARP5414B that there is a need for validation. Such an activity is obviously essential for new shapes as VTOL with multi-rotor configurations for which experience is rather absent. Existing electromagnetic tools can be used, but still need validation for a better prediction. The final goal would be to have a validated means of compliance or at least as an intermediate step a help for the design of protections and the certification phases. The first part of the paper provides an overview in terms of in service experience and zoning tools based on Airbus experience. The second part reports the results obtained on a complete Helicopter with the Airbus electromagnetic numerical tool for primary attachment locations prediction, the limitations of such a prediction tool and the recommendations in terms of utilization of the tool and associated protection policy.
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4296300993