Scott Anderson knows most people may think he is to blame after seeing footage and reports of a helicopter crash in Auckland's Viaduct.

A line attached to the top of a 25m Christmas tree mast was stuck in the helicopter's hook and swung 30cm above Mr Anderson's reach.

The helicopter was coming down towards him and the pilot made eye contact, Mr Anderson says.

"Eyeball to eyeball ... There was no doubt in my mind he was trying to get that rope in my hand."

So Mr Anderson jumped - and in "6.5 seconds of mayhem", the line hit a rotor, sending the helicopter crashing down and beginning 14 months of distress for all involved.

Reports into the incident claim the crash was precipitated by poor planning, questionable equipment and dangerous work methods - though none of it was serious enough to warrant prosecution, according to a Civil Aviation Authority document.

Some of the issues are detailed in final or near-final drafts of Civil Aviation's reports obtained by the Herald, while others were discovered by an investigator commissioned by one of the insurance companies.

Civil Aviation is set to publicly release its reports this week.

"It's been hanging over me," said Mr Anderson, the rigging supervisor on the day.

When the accident happened, he was lost, he said. He didn't even know how to leave the scene. An ambulance eventually took him away.

He was approached by a lawyer from his insurance company, who Mr Anderson said had indicated he was trying to get the company out of the claim.

His name and company were all over newspapers and television, with reporters camped outside his work and home.

He said he had since been receiving fewer offers of work and his insurance premiums had jumped $10,000.

But, he said, many people had supported him. The helicopter should never have been descending towards him, and the lower it came the higher the risk was becoming, he said.

Civil Aviation's reports, which put in bold type that their purpose is not to apportion blame or liability, say Mr Anderson committed the "dangerous action" but the pilot had "unwittingly created a dangerous situation".

Issues raised in the reports include the fact that the line used was only 30m long - meaning the helicopter would have difficulty landing once the 25m mast was upright, if the hook's release mechanism failed.

Mr Anderson said his insurer, Vero, commissioned an investigation to further examine the crash.

It found that a manufacturer had issued a notice to replace an internal spring in the type of hook used on the helicopter. Compliance was optional. The original spring was causing inconsistent latching on its release mechanism, says the notice by Onboard Systems.

The notice, issued in 2003, said the original springs could cause loads to be dropped. The spring, the investigation said, had not been replaced.

Mr Anderson said he was disappointed that the Civil Aviation Authority had not even looked at whether the hook could have been faulty.

The pilot, Greg Gribble, said he would double- and triple-check his equipment but he knew of no issues.

"Everything is totally above-board ... on our side of things. Civil Aviation have found nothing to do with our hook," Mr Gribble said.

Issues with set-up

Hook didn't operate
The line connecting the helicopter to the Christmas tree mast didn't unhook as it should. The pilot and rigger had feared this could happen because the line was light and didn't weigh down on the hook.

Line was too short
The line between the helicopter and mast was less than 30m. The mast was 25m high. When the hook failed to release the line, there was little room to manoeuvre.

Line was too light
The pilot wanted to put a chain at the end of the line to give it weight. However, the rigger said it would be dangerous for workers on the ground when the heavy chain fell from the air. The chain was not used.

The team's contingency plans
*Bring the helicopter low enough to slide the line off the hook.
*Fly straight up until the weight of the Christmas tree mast pulled the line off.
*Have someone climb the tree mast and unhook the line.

- Sources: Civil Aviation Authority/VFR Consulting