It was powered by a 575 hp (429  kW) Bristol Jupiter XFA radial engine, having a defensive armament of one forward-firing Vickers machine gun and a Lewis gun on a Scarff ring on the observer's cockpit.

It could carry either the planned 1,000 lb (455 kg) torpedo under the fuselage or an equivalent weight of bombs under the wings.

[2] It first flew in February 1931, showing good performance (in particular, a high ceiling) and handling when tested by the Aeroplane and Armament Experimental Establishment at Martlesham Heath.

[3] The aircraft, now registered G-ACAZ, was remodelled with a rear cabin and a 630 hp Bristol Pegasus engine driving a large diameter propeller.

[4] It was test flown from Yeovil in the new configuration, and on 25 January 1933 reached a height of 35,000 ft.[5] Flown by Lord Clydesdale with Stewart Blacker as observer and photographer,[6] it was accompanied by the Wallace as, on 3 April 1933, the two aircraft became the first to fly over Mount Everest, flying over Kangchenjunga on 4 April and making a second flight over Everest (as the initial flight had produced inadequate photographs for map-making) on 19 April 1933.