A Blenheim pilot who died while attempting a prestigious 1000km glider flight encountered significant turbulence before the aircraft crashed nose-first into a ridge, an investigation has found.
Experienced glider pilot Mike Dekker, 55, was killed when his glider crashed into Orchard Spur, about 14km south of Blenheim, on December 18, 2009.
A Civil Aviation Authority (CAA) report, released today, said its investigation could not determine the cause of the crash for certain, but there was no indication that mechanical failure had contributed.
Mr Dekker, who had almost 2000 hours gliding experience, had been on his 12th attempt to qualify for a 1000km gliding badge and diploma - an achievement the CAA said would have earned him prestige and respect among his peers.
He was the national operations officer for Gliding New Zealand and was a senior member of the local gliding club.
The CAA report said the Mini Nimbus HS7 glider was released by a powered tow plane at about 8.30am after taking off from Blenheim's Omaka aerodrome.
Mr Dekker had intended to fly across the central South Island, back to the Blenheim area, and south again to Central Otago before returning to the aerodrome.
Instead, the glider hit terrain in a steep nose-first dive just 34 minutes after take-off.
Its GPS unit showed Mr Dekker had been ridge soaring as he made his way up a valley in an attempt to gain height. At the last recorded position, the glider was about 400 feet above terrain.
The investigation found the glider was likely struck by massive turbulence and downdraughts before the crash.
Mr Dekker was known to have a heart condition but there was only a small chance it had led to the crash.
The investigation found there was little chance he would have survived, but noted the alarm was not raised until that evening.
The CAA said that served as a reminder to the gliding community to ensure adequate flight following [maintaining contact with an aircraft] on long-distance flights.
Another glider pilot was killed a short distance up the valley in an earlier crash in 1998.