A crash report has found the pilot was a long-term cannabis user and that it was highly likely he'd smoked marijuana shortly before the ill-fated flight.
As New Zealand correspondent Dominique Schwartz reports, it's prompted calls for tougher regulations covering alcohol and drug use across the aviation, maritime and rail transport industries.
Presenter: New Zealand Correspondent, Dominique Schwartz
DOMINIQUE SCHWARTZ: It was perfect weather for a joy flight when the Cameron Balloon A210 lifted off from the rural village of Carterton early on January the 7th. But the ride of a lifetime only ended the lives of pilot Lance Hopping and his 10 passengers, among them Val Bennett. Her family gave her the ticket as a 70th birthday present.
NICKY BENNETT: Val had for many, many, many years gone to the balloon festival each year and was often wondering what it would be like to take that flight.
DOMINIQUE SCHWARTZ: Val Bennett's daughter-in-law Nicky Bennett says the final report of the Transport Accident Investigation Commission makes for difficult reading, particularly hearing that cannabis may have played a significant role in pilot Lance Hopping's poor judgment.
NICKY BENNETT: To now know that he was so impaired that he couldn't even get to the point of making an emergency decision to save those people's lives is pretty horrific and devastating.
DOMINIQUE SCHWARTZ: Accident investigators say toxicology reports show evidence of long-term and recent cannabis use by the pilot. Two witnesses reported seeing him smoking 25 minutes before take-off. He was not a cigarette smoker.
The head of the Investigation Commission, John Marshall, says it was highly likely that Lance Hopping had ingested marijuana shortly before the flight.
JOHN MARSHALL: The accident was caused by errors of judgment by the pilot. The possibility that the pilot's performance was impaired as a result of ingesting cannabis cannot be excluded.
DOMINIQUE SCHWARTZ: The commission says the pilot's decision to fly the balloon low over a paddock bounded by power lines was unsafe. As the balloon rose, it caught the electricity wires. What happened next possibly cost those on board their lives.
JOHN MARSHALL: Once a collision with power lines is imminent, the recommended action is for the pilot to descend the balloon rapidly. Had he done so, there would have been a better chance of survival for the balloon's occupants.
DOMINIQUE SCHWARTZ: The president of New Zealand's Balloon Aviation Association, Martyn Stacey, agrees.
MARTYN STACEY: The maxim for balloons is: contact the power lines, rip out, hit the ground. Yes, you're going to have a hard landing but, nine times out of 10 it should be survivable.
DOMINIQUE SCHWARTZ: Instead the balloon ascended, caught fire and crashed to the ground.
Martyn Stacey knew Lance Hopping as an experienced and responsible commercial pilot who'd been flying balloons for 15 years. The revelations of his drug use came as a shock.
But the Transport Accident Investigation Commission says substance impairment appears to be a growing problem. It's been a feature in six cases over the past 10 years, which have claimed 34 lives.
The Commission is again calling for tighter rules and regulations covering alcohol and drug use across the aviation, maritime and rail transport industries; a plea echoed by victims' relatives, such as Nicky Bennett
NICKY BENNETT: If you do not have the fear of the random testing, people will get complacent. It's human nature. We all do it. You've got to have the random testing in place.
DOMINIQUE SCHWARTZ: Ballooning president Martyn Stacey says random testing is already being carried out by operators under changes to adventure aviation rules implemented since the Carterton balloon tragedy.
MARTYN STACEY: The person that comes around doing spot checks is independent of the company.
DOMINIQUE SCHWARTZ: But it could be another ballooning company?
MARTYN STACEY: It could be another ballooning company. In fact, a lot of balloon companies now check each other, 'cause if you are in a one-man band, how do you check yourself?
DOMINIQUE SCHWARTZ: But Nicky Bennett believes that nothing short of an industry-wide independent regulator carrying out checks will do. It won't bring back those who've been killed, but she says it may prevent another tragedy.