LIHU'E, Kaua'i — A survivor of a fatal helicopter crash off Ha'ena said he welcomes a criminal investigation into the pilot's actions, if only because it may clear up what happened that day in September.

There were "a lot of inconsistencies" in the account that the pilot gave, survivor Bill Thorson Jr. said yesterday from his home in Beloit, Wis. But "this will answer a lot of questions for me."

Kaua'i Prosecuting Attorney Craig De Costa said his office is conducting an investigation just as it would into a fatal auto accident with a surviving operator who might be criminally responsible.

Such investigations in tour helicopter crashes are rare because in most such crashes, the pilot is among the fatalities, he said.

In each of the nine other helicopter crashes in Hawai'i since 1995 in which there was at least one death, the pilot was killed. The National Transportation Safety Board has completed its investigation into six of those crashes, and in each case, pilot error was either the primary or a contributing cause.

Pilot Glen Lampton and five passengers were on a Heli USA Airways circle-island tour Sept. 23 when the Aerospatiale helicopter flew into a rainstorm over the ocean off north Kaua'i. The helicopter lost altitude quickly, crashed into the sea, rolled over and sank.

Newlyweds Thorson and his wife, Karen, made it out of the sinking fuselage and survived, along with pilot Lampton.

The passengers who died were Karen Thorson's father, Laverne Clifton, 68, of Beloit, Wis., and Catherine Baron, 68, and Mary H. Soucy, 62, both of Portland, Maine.

A National Transportation Safety Board investigation is still under way, and word of a county prosecutor's criminal investigation surfaced this week when subpoenas for film footage of the helicopter were delivered to local television stations.

Heli USA vice president John Power said that while investigations are necessary, he wonders whether a criminal investigation is appropriate.

"Obviously, we know that there's investigations going on by the NTSB, FAA and local authorities. The NTSB said it's normal when there's fatalities for local authorities to run an investigation. I'm just surprised that a prosecutor would be looking at a criminal investigation of what was an accident," he said.

Lampton told investigators he flew into the rainstorm, but he also told them that he did so while maneuvering to avoid an oncoming helicopter.

The Thorsons, however, said the only helicopter in sight was far below the Aerospatiale. And the pilot of the helicopter that Lampton appeared to have identified also said he was flying many hundreds of feet below Lampton's altitude, and was miles away when he heard Lampton's emergency radio reports.

Bill Thorson said: "We're still wondering why he flew into it. I'm glad that they're investigating and the truth will come out."

De Costa downplays any suggestion that his office's investigation is setting a precedent.

"We want to do a complete and fair investigation before we decide whether to bring charges and what charges to bring. Any time there's a death in the County of Kaua'i that may have a responsible party subject to criminal liability, we have to look into it," he said.

He said the probe was not requested by the FAA, as some reports have indicated, and FAA spokesman Donn Walker agreed.

"We did not request an investigation. We don't do that," Walker said.

At Heli USA, Power suggested Lampton was caught by unusual conditions in weather that other helicopter pilots elected to fly into and were able to escape, either by flying through or turning to get back out.

"There were three or four other pilots in that weather at the same time. Nearly every accident in Hawai'i in recent years has involved weather," he said.

Pilots are trained to make reasoned determinations about the conditions in which they fly, Walker said.

"A lot of discretion is given to pilots. They use their eyes. They use their instruments. That's what they're trained to do," he said.

Lampton has left Kaua'i and is still technically an employee of Heli USA Airways, but he has been suspended from flight operations and is not actively working for the firm, Power said.

Thorson said that he has agreed to cooperate with county investigators, but that he and his wife have not been interviewed. He said the family is still struggling to recover from the loss of his wife's father in the crash that nearly cost the couple their lives.

"We've been to counseling a couple of times. The holidays are coming up, and that's going to be tough," Thorson said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.