 The night fighter version of the Avro 504K was also armed with a "modified S.E 5a" type Foster mounted Lewis gun (see illustration at the head of this article).This aircraft had a much larger gap between the top of the fuselage and the upper wing than most types fitted with this mounting and must have proved very awkward to use.On the B.E.12b, intended as a night fighter, over-wing Lewis guns relied on makeshift mountings, including one that resembled the original double hinged mounting on early French Nieuports.