Recently, safety requirements to prevent fuel tank explosion have become stricter. To show
compliance with these requirements, Mitsubishi Aircraft Corporation designed the wing fuel tank
of the Mitsubishi Regional Jet (MRJ) with a sufficient margin of safety based on three-dimensional
electromagnetic simulation and coupon tests. To build further confidence in the safety of the MRJ,
which is not yet in service, and to obtain data supporting the type certificate, the occurrence of
ignition sources causing fuel ignition in wing fuel tanks is investigated by lightning tests using a
full wing model, and the potential difference and current are also measured. The full wing model
includes the majority of the MRJ wing structure and is manufactured by the same process as actual
wing manufacturing. Such a large-scale test is a rarity around the world. In the tests, lightning
current (200kA max.) specified by ARP5412, which is one of the standards for aircraft lightning
tests, is injected to the full wing model. In all cases that were tested, it was confirmed that no
ignition sources are generated inside the wing fuel tank and that the potential difference and
current inside the tank are sufficiently low.
