Air Accident Investigation Branch Wants More Training For Sport Pilots

Since 1989, there have been as many as 265 gyroplanes flying in the United Kingdom. Also since 1989, there have been 15 fatal gyroplane accidents in the UK. That works out to a fatal accident rate of 27.1 for every 100,000 hours of flight time. So says the British Air Accident Investigation Branch. The fatal accident rate for all other forms of aviation in Britain is 1.1 per 100,000 flight hours.

Now, AAIB has issued a report critical of gyroplane technology and the training of gyro pilots. The report, which focused on the July 29th, 2003 crash of a modified Ponsford Bensen B8MR, in which 44-year old Ian Broderick Pitt-Steele of, Gardyn Croft, Taverham, on his first unsupervised solo flight in a gyroplane, plunged more than 250 feet to his death.

Porpoising

AAIB investigators wrote:

On the morning of 29 June... G-BIGU appeared to takeoff from Runway 02 and fly a short distance to the north before turning back towards the airfield. The aircraft was seen to fly along the runway in each direction and some witnesses were aware of G-BIGU gently "porpoising" as it flew along.

Estimates of the height of the gyroplane during this time varied between 10 and 20 feet above the runway and also between 400 and 500 feet but displaced to one side of the runway. With the variation in height estimates from the witnesses, who were both pilots, it was possible that this "porpoising" occurred at different times. None of the witnesses were concerned by the maneuvers. One witness, who saw the last moments of flight, was standing by the airfield hangar looking towards the east. He saw G-BIGU in a downwind position for Runway 20 at about 250 to 300 feet AGL and at an estimated speed of about 45 kt.

The gyroplane appeared to be stable and in level flight when the witness heard a single "bang" and saw an immediate change in attitude. The aircraft pitched nose down and fell vertically to the ground. This witness also commented that he had heard a "broken" radio transmission sometime prior to the accident sequence; with no other club aircraft flying, he assumed that the pilot of G-BIGU had made this transmission.

The Cause

In its synopsis, the AAIB wrote:

[The accident] resulted from the rotor blades striking the rudder, which rendered the gyroplane uncontrollable. Witness accounts indicated that G-BIGU was flying straight and level at a reasonable speed just before this event, although there were reports of possible 'over-controlling' during the flight. The specific reason for the rotor blades striking the rudder could not be determined but a pilot induced oscillation appeared to be the probable cause.

An examination of the aircraft, and subsequent computer modelling by the University of Glasgow indicated that the aircraft could have had poor longitudinal stability characteristics. The investigation also highlighted the poor safety record of gyroplanes in general compared to other types of recreational aircraft. Accordingly, recommendations have been made concerning the approval of gyroplanes and the training and licensing of gyroplane pilots.

The test flight of G-BIGU that was carried out on behalf of the Popular Flying Association did not appear to have been flown in accordance with the interpretive material of the stability requirements of British Civil Airworthiness Regulations Section T. The flight test report did not include any data to support the opinion that the aircraft met the dynamic stability criteria of section T. The format of the form used for the flight test report was poor in that it did not include fields for recording the data required by British Civil Airworthiness Regulations Section T.

Technical Problems?

The AAIB was highly critical of the procedure by which the aircraft itself was certified as airworthy:

The test flight of G-BIGU that was carried out on behalf of the Popular Flying Association did not appear to have been flown in accordance with the interpretive material of the stability requirements of British Civil Airworthiness Regulations Section T. The flight test report did not include any data to support the opinion that the aircraft met the dynamic stability criteria of section T. The format of the form used for the flight test report was poor in that it did not include fields for recording the data required by British Civil Airworthiness Regulations Section T.

AAIB recommendations include:

• Better gyroplane pilot training, especially in type and especially in flight
• Differentiating between hours spent "wheel balancing" (a maneuver whereby the pilot lifts the nose of the gyroplane off the ground as he moves down the runway, but does not actually take off)
• Ensuring gyroplane test pilots are trained to evaluate aircraft performance

Finally, on the issue of flight certification for gyroplanes, the AAIB concluded:

The Popular Flying Association also endorsed the recommendations and stated: "We are now working with the CAA Projects Department and Flight Department to develop a new gyroplane flight test schedule specifically to investigate ultralight gyroplanes against the Section T handling requirements, and to train selected experienced gyroplane pilots in the test methods and reporting procedures. We are of course working with the CAA on the re-evaluation of existing types of gyroplanes against Section T handling requirements which we see as a very positive step towards addressing the high accident rate on this class of aircraft".

FMI: AAIB Report