What happened
Following a 100-minute flight intended for US certification testing, the Bristol 175 was returning to Filton. The mission had involved high-speed upset maneuver recovery trials and strain-gauge measurements on an unconventional propeller attached to the number two engine. During the approach, the aircraft entered a circuit pattern where several partial extensions of the landing gear occurred for undetermined reasons. It is possible that efforts were being made to conduct unprogrammed undercarriage free-fall tests following a failure during the previous day's operations.
While flying at an altitude of 1500 feet, the crew began a left turn toward the base leg. During this maneuver, the right wing experienced a sudden drop, forcing the aircraft into an extremely steep right-hand bank. Although the pilot managed a brief period of recovery, the aircraft entered another deep bank and ultimately impacted the ground in a wooded area located near a residential neighborhood. The accident resulted in fatalities (count not specified in source) and occurred during the landing phase.
Findings
Investigations concluded that the crash was caused by the aircraft entering an uncontrollable, steep descending turn to the right. While the exact trigger for this loss of control could not be definitively identified, investigators noted that a malfunction within the autopilot system remained a possible contributing factor.