Glider pilot's battery caught fire mid-flight, causing fatal 2017 crash in Northland

The Civil Aviation Authority (CAA) has issued a warning to pilots after finding a 2017 fatal glider crash in Northland was likely caused by an onboard lithium battery bursting into flames.

The CAA has released its safety investigation report into the death of a 72-year-old pilot, who took off from Kaikohe Aerodrome in November of 2017.

The pilot, Rico Legler, was flying a Pipistrel Taurus Electro G2, which differs from conventional gliders because it has a built in battery-powered retractable propeller to launch itself and sustain speed during flight.

During the flight, one of the aircraft's lithium polymer batteries is believed to have caught fire, filling the cockpit with fumes and smoke.

The CAA said the pilot then undertook an emergency descent towards the aerodrome, but in doing so, they exceeded the speed the glider was built for, and it failed structurally.

The glider's wings collapsed and the aircraft suffered a "non-survivable" impact with the ground.

CAA Aviation Safety Deputy Chief Executive Dean Winter said "batteries must be charged and properly maintained according to the manufacturer's instructions.

"If battery damage is suspected due to a sudden impact they must be checked before flying again.

"Battery fires burn at a very fast rate, releasing significant energy and toxic fumes and within seconds a cockpit can be filled with toxic smoke - these fires can be deadly and spread quickly."

At the time of the crash, it was the only battery-powered glider in New Zealand.