The danger first came to light in a near-crash during a 1962 test flight when de Havilland pilots Peter Bugge and Ron Clear were testing the Trident's stalling characteristics by pitching its nose progressively higher, thus reducing its airspeed. The Trident entered a deep stall after a critical angle of attack was reached. Eventually, it entered a flat spin, and appeared to be about to crash, but a wing dropped during the stall, and when corrected with rudder the other wing dropped. The aircraft continued rolling left and right until the nose pitched down and the crew were able to recover to normal flight. The incident resulted in the Trident being fitted with an automatic stall warning system known as a "stick shaker", and a stall recovery system known as a "stick pusher" which automatically pitched the aircraft down to build up speed if the crew failed to respond to the warning.