Incident Overview

Description
G-ASJD, with a crew of two test pilots and two flight test observers, was being flown on pre-certification stalling tests, with the centre of gravity at 0.15 standard mean chord, the furthest forward position for which the aircraft was then cleared. For the purposes of the test flying programme, the aircraft was fitted with a tail parachute and with modified engine reverse thrust cascades; these two modifications were designed to produce powerful nose-down pitching moments, if an excessively high angle of incidence was experienced during the stalling tests. During the first test run at just over 20000 ft. the aircraft developed a slight oscillation in pitch and the pilot decided to recover and begin again. During the intended recovery, he gained the impression that the aircraft’ s response to elevator movement was not normal and that the aircraft might be in a stable stall. The tail parachute was therefore streamed although the IAS had by then increased to 225 knots and the incidence was 6ø. Forward and upward thrust was also applied on a number of occasions, but this served only to increase the pilot’s conviction that a stable stalled condition existed. Late in the descent it was found that full flap and full power reduced the rate of descent considerably, and a wheels-up landing was made on undulating grassland. The aircraft was relatively little damaged in the ground slide and none of the crew were injured. It was concluded that, when the pilot pushed the control column forward after the stalling run, the aircraft had responded correctly as indicated by the instruments. Under the erroneous impression that the aircraft was in a stable stall however, the pilot streamed the tail parachute and it was the retention of the streamed parachute that made the emergency landing necessary. Had it been jettisoned during the descent, the flight could have continued normally.
Primary Cause
Pilot error ? inducing a stable stall through improper control input and retention of the tail parachute.Pilot error ? inducing a stable stall through improper control input and retention of the tail parachute.Share on: