[Col Bruggy]

Hello,

From Ian Thirsk's , de Havilland Mosquito Vol.2:

W4050, The Mosquito Prototype.

In early February 1941 W4050 received a coat of Dark Earth and Dark Green camouflage on its upper surfaces in readiness for service acceptance trials at the A&AEE Boscombe Down (large 'circle P' markings also being applied to the fuselage sides aft of the roundel). Delivered to the Performance Testing Squadron at Boscombe Down on 19 February, W4050 greatly impressed the A&AEE test pilots, but on 24 February, while being taxied by Flt Lt Slee, W4050's fuselage fractured after after the tailwheel jammed (due to a castoring problem) on Boscombe's rough aerodrome surface.The late Air Commodore Allen Wheeler was in charge of the Performance Testing Squadron at this time and recalled that Flt Lt Slee was initially unaware of the problem until all of W4050's controls tightened up. Airmen were called over to check through the control lines, one of them eventually shouting out from beneath the Mosquito: ' It's all right, sir, there's nothing wrong with the controls but she's broken here bleeding' back.' The fuselage had fractured around the access hatch cut out on the starboard side, damage being extensive enough for the decision to be taken to change the fuselage with that destined for W4051, the Photo Reconnaissance prototype. A small working party was despatched to Boscombe Down to fit this new fuselage, W4050 returning to Hatfield on 14 March (an externally mounted longitudinal stiffening strake was subsequently mounted above the hatch cut-out, this later becoming a standard feature of production aircraft).

See:
de Havilland Mosquito An Illustrated History Volume 2.
Thirsk, Ian.
Manchester:Crecy Publishing,2006.
p.15.

Col.