Helicopter at night Photo: 123RF
An investigation into a fatal helicopter crash in Otago has found the rules around night flying are ambiguous and pilots should regularly refresh their skills.
The Airbus helicopter AS350 B3e ZK-IT pilot died after losing control and spiralling into the ground near the Lammerlaw Range while enroute to an Alexandra cherry orchard to do frost protection on 16 September 2021.
The Transport Accident Investigation Commission report said the pilot was an experienced aviator who was trained and qualified for restricted night flying.
But it found the pilot left during one of the darkest parts of the night and almost certainly encountered cloud and was trying to move around it.
"With increasing cloud cover and little or no terrestrial light in the Lammerlaw Range area, it was very likely that the pilot lost their clearly defined horizon soon after passing Lawrence."
The helicopter climbed straight ahead for close to three minutes.
The report then found the pilot very likely became disorientated, resulting in a high angle bank turn before rapidly descending.
While the pilot met the current rules for restricted night flying, it had been nine years since they last logged practice using instruments only, the Commission said.
"It was very unlikely that the pilot was proficient in flight with sole reference to aircraft instruments at the time of the accident."
The Commission found the rules and guidance around visual night flying were ambiguous and didn't make it necessary for pilots to regularly train or be assessed.
That could lead to pilots flying longer distances than allowed at night or encountering conditions they didn't have the skills for, it said.
"The current rules for and guidance on instrument currency for night (Visual Flight Rules) do not adequately mitigate the risks of inadvertent flight into conditions where the clearly defined horizon is lost."
The Commission recommended pilots regularly refresh their night flying skills and ensure they have the right training for the different types of night flying.
"The risk of losing a clearly defined horizon by not remaining clear of cloud and in sight of the surface increases when flying at night.
"An immediate transition to instrument flight is required to maintain situational awareness and control of the aircraft in order to re-establish a clearly defined horizon."
It also recommended tracking technology was used to reduce the time taken to locate missing aircraft.
