THERE is not enough evidence to determine the cause of an air crash in Fenland in which the pilot was killed.

An Air Accidents Investigation Branch report also found it was possible that the pilot, 70-year-old Francis Ball of Tholomas Drove, Wisbech St Mary, may have become incapacitated in the final stages of the flight.

Mr Ball, a highly experienced pilot, died when the modified light aircraft crashed on the outskirts of Coates on November 8 last year.

The G-MISS aircraft, a modified Taylor Titch, was owned by David Beale of Sutton. It was Mr Ball’s first trip in this type of aircraft.

Mr Ball was briefed to fly a few stalling exercises followed by a few circuits back at the airstrip. The report said the weather was good when the aircraft departed.

The report said: “It was last seen by the owner at a height of approximately 2,000ft, several miles to the north of the airstrip in a left turn.

“Witnesses saw a small aircraft enter a steep spiral dive, complete several revolutions, then crash into a bank on the edge of the River Nene.”

The aircraft was granted its permit to fly in August last year after the owner completed more than 16 hours of flight testing. The flight test report concluded that G-MISS “performs well and is pleasant and easy to fly”.

The owner gave Mr Ball an extensive brief on the handling characteristics of the aircraft, before briefing him to climb to height in the airfield overhead and carry out some general handling including stalling. The flight was expected to last about 20 minutes.

The report said: “The aircraft was a little difficult to start, as the engine was still warm from the previous flight, but after starting the pilot carried out his normal checks, including the magneto checks, and taxied out to Runway 36.

“The departure, at about 3pm, was described by the owner as “a bit messy” as the pilot seemed to have some difficulty in controlling the heading as the aircraft progressed down the runway. This may have been due to the fact that the propeller rotated in the opposite direction on G-MISS to that on the pilot’s own Isaacs Fury.

“The owner commented that the aircraft’s climb angle was not as steep as he was expecting and he wondered whether the pilot had left the carburettor heat selected, as he had taxied out with it on.

“The owner saw the aircraft turning left, assumed it was returning to the airfield but then he lost sight of it. After 30 minutes, when the aircraft had not returned, the owner became concerned and initiated ‘overdue’ action.”

A witness walking with her husband along the flood dyke to the south of the River Nene near Eldernell described the noise of an aircraft suddenly reduce. They saw the aircraft in the air, then heard the engine noise increase.

Shortly afterwards, however, the aircraft entered the descending spiral turn which became very steep after several rotations. It eventually crashed 200 metres away from them on the bank of the river.

The husband ran to the accident site but the report said: “It was immediately apparent that nothing could be done to assist the pilot.”

Another witness was watching birds near Eldernell through binoculars when the aircraft came into his field of view.

The report said: “He had previously flown gliders and considered that he was witnessing a spiral dive, not a spin. He initially thought that the aircraft was performing aerobatics but became concerned as the aircraft continued to descend.

“The aircraft hit the ground about a mile from his position and he heard a noise which he described as a thump. He called the emergency services and proceeded to the aircraft.”

Mr Ball had a medical condition known as atrial fibrillation, the most common abnormal heart rhythm, and was admitted to hospital in 2008.

A post mortem examination revealed that the pilot had suffered multiple severe injuries, which were consistent with being caused by the aircraft striking the ground. The toxicology tests revealed no evidence of alcohol or drugs in the pilot.

A specialist aviation pathologist also reviewed the pilot’s medical history and the post mortem results, and considered that it was possible that the pilot had suffered an incapacitating cardiac event just prior to the accident.

The report also said the aircraft could have entered a spiral manoeuvre if it had suffered from a control restriction or failure. However, the engineering investigation concluded that the aircraft was structurally intact at impact and that there had been no pre-impact disconnection or failure of the flying control mechanisms.

“No foreign objects were recovered which could have caused jamming of the flying controls,” it said. “Consequently, the aircraft ought to have been recoverable from either a spin or a spiral dive if the correct control inputs had been made.

“Another reason for a spiral dive, or spin, could have been pilot incapacitation. The investigation noted that the cause of death given by the pathologist was multiple injuries but that it was possible that the pilot had suffered an incapacitating cardiac event just prior to the accident.”