English: Mosquito NF Mark II, DD609, fitted with AI Mark IV radar, parked at the de Havilland's aerodrome, Hatfield, It was later delivered to the Aeroplane and Armament Experimental Establishment at Boscombe Down for tests. DD609 later saw service with No. 151 Squadron RAF, and later with 54 Operational Training Unit.

Details of the AI Mk. IV antenna system are evident in this image. The transmitter antenna is mounted on the nose, and the vertical dipoles of the horizontal receiver antennas can be seen near both wing tips. The lower vertical receiver antenna can be seen near the landing light (the circular object on the bottom of the near wing); the upper antenna is directly above it, obscured behind the wing in this image.

This image appears to be at the end of a demonstration flight for a visit by the Duke of Kent to the de Havilland plant in November 1941. See E(MOS) 516 for a very similar image with the engines still running.