Carterton tragedy: 'Pilot failure' blamed

A tribute in Carrington Park, Carterton for the victims of the fatal crash. Photo / APN

The Carterton hot air balloon tragedy was probably caused by a pilot who may have been impaired by long-term cannabis use and who failed to take timely evasive action to avoid wires, an inquest has been told.

All 11 people on board were killed when the balloon crashed on January 7, 2012.

The inquest, in front of Coroner Peter Ryan at the Wellington District Court, heard its third day of evidence today - including evidence about pilot Lance Hopping's use of cannabis.

Australian forensic pathologist Shelley Robertson said, via video link, that Mr Hopping could have been impaired by cannabis, even if he had not smoked it on the day of the tragedy.

The hot air balloon, carrying Mr Hopping and 10 passengers, caught fire and crashed into a field after hitting powerlines in Carterton in January 2012.

The Transport Accident Investigation Commission report found errors made by Mr Hopping, 53, ultimately resulted in the crash. It also established he had cannabis in his system at the time of the accident.

Experts yesterday told Coroner Ryan that the measurement of 2 micrograms per litre of blood, found in Mr Hopping's system, was unreliable because his long-term cannabis use - coupled with the delay in retrieving samples from his body - could have altered the actual amount in his system.

Dr Robertson agreed it was impossible to know exactly how much THC, the active ingredient in cannabis, was in Mr Hopper's system, but there was clearly some.

"The pilot definitely used cannabis and I can not exclude the possibility of impairment and I can not exclude that that impairment did not contribute to the tragedy.''

Cannabis use could affect a user longer than 24 hours after use, Dr Robertson said.

Also today, via video link, UK ballooning expert Phil Dunnington said according to recommended emergency procedure, Mr Hopping should have begun an emergency descent when it became clear the balloon was at risk of striking power lines. However, he decided against this and tried to out-climb the wires.

"Pilot failure to take account of wires and take timely evasive action'' was the most likely cause of the crash, Mr Dunnington said.

Coroner Ryan said he was considering making recommendations around emergency pilot training and cannabis education in the adventure aviation industry.

He asked Mr Dunnington whether further pilot training may help to prevent accidents like the Carterton balloon tragedy.

"There's no harm in increased training. You have to make sure that the training is focused on achievable goals. For instance, there's no point at all in trying to train people on how to deal with an explosive propane fire because the only thing to do is, if your on the ground to run away, and if your in the air - you don't have any options as we found in this case,'' Mr Dunnington said.

Coroner Ryan also said he was considering a recommendation implementing education around the effects of cannabis use for commercial balloon pilots.

The inquest was due to finish tomorrow, but could now continue into Friday.