The original PV-6 prototype, registered G-ACBR (and also known as the Houston-Wallace) along with Westland PV-3 G-ACAZ, was part of the Houston Everest Expedition, named after Lucy, Lady Houston the patron, an attempt to fly over Mount Everest. Both aircraft received modifications that included fitting heating and oxygen equipment, fully enclosing the rear cockpits and using highly supercharged Bristol Pegasus IS 3 engines. Flown by Flight Lieutenant D.F. McIntyre and Douglas Douglas-Hamilton, 14th Duke of Hamilton, otherwise known as Lord Clydesdale, the two aircraft became the first to fly over Mount Everest on 3 April 1933.