The prototypes performed well; however, design failings led to the loss of "WB771" on 14 July 1954, when the tailplane detached whilst making a low-level pass over the runway at Cranfield, causing the aircraft to crash with the loss of the crew. Attached to the fin using three bolts, the tailplane was subjected to considerably more load than had been anticipated, causing fatigue cracking around the bolt holes. This led to the bolts loosening and failing in shear. Stress concentrations around the holes were reduced by adding a fourth bolt. The potential for flutter due to shortcomings in the design of the fin/tailplane joint was also reduced by shortening the fin. Additionally, the prototypes were tail heavy due to the lack of equipment in the nose; this was remedied by adding large ballast weights to the prototypes. Production Victors had a lengthened nose to move the crew escape door further from the engine intakes as the original position was considered too dangerous as an emergency exit in flight. The lengthened nose also improved the center of gravity range.