National Transportation Safety Board investigators on Monday flew over the site of a fatal sightseeing tour helicopter crash on Kauai, and will try, among other things, to get “boots on the ground” today, the lead investigator said.

NTSB lead investigator Eric Weiss could not provide with any level of detail a description of the wreckage or the precise location of Thursday’s crash that killed seven, nor did he know the pilot’s background but promised to have more details today.

Paul Ray Matero, 69, who was piloting the Eurocopter AS-350-B2 for Safari Helicopters was not certified to fly using instruments, according to the Federal Aviation Administration’s database.

If he had run into bad weather in Kokee as some, including Kauai Fire Department officials and Matero’s wife, Donna Dublin, have suggested, “he’s not going to have the skill and ability to maintain the helicopter without a visible horizon,” said Robert Katz, a Dallas-­based flight instructor and pilot of 38 years.

“I don’t know what the weather conditions were like … but flying over this type of terrain, which is subjected to low ceilings, low visibility, all other issues aside, leads me to believe he got caught in the clouds and quickly became disoriented,” said Katz, who tracks plane crashes nationwide.

“He would not be able to read the instrument because he’s not instrument-qualified,” he said. “It’s a mistake pilots often make. It takes specific training to earn the instrument-helicopter qualification.”

Katz opined that any pilots taking the route should be instrument-qualified.

“His rating of rotocraft-helicopter by itself means he can only fly for hire when he can see where he’s going,” Katz said. “It’s a skill that would have saved the day.”

Passengers Amy Gannon, 47, and her 13-year-old daughter, Jocelyn, of Madison, Wis., were killed. The Associated Press reported Gannon’s husband and son did not take the flight, but were still in Hawaii Saturday.

A Swiss family of four — a woman, 50, a man, 49, and two girls, ages 13 and 10 — whose identities have not been released, also are believed to have died in the crash.

Six sets of remains were recovered Friday. On Saturday, police said there were no survivors but could not confirm the seventh person’s remains were recovered.

From Kauai Fire Battalion Chief Solomon Kanoho’s description that the chopper hit a cliff face, then dropped between 150 and 300 feet, Katz surmised the helicopter was totally destroyed.

“These crashes are always high energy,” Weiss said.

Dublin said her husband was safety-oriented and flew the Na Pali tour about four days a week. She said her husband watched the weather at home and at work, warning customers about taking the tour if there was the possibility of windy or rainy conditions because he didn’t want them feeling airsick.

Katz said Matero “made a bad choice. I’m sure he could have seen the weather before he got to it.”

He added, “the whole point of a tour is to give people closer views of waterfalls, so a pilot is flying close to the terrain,” and “if he’s swamped by cloud cover or fog and flying very low to the surface,” he can’t see where he’s going.

Katz also said that getting instrument qualified would require renting a smaller helicopter at $500 an hour for 40 hours. That would amount to $20,000.

Matero had flown helicopters for more than 40 years — 12 on Kauai, according to his employer and wife, and held a mechanic’s certificate. He had “reached the pinnacle of his aspirations,” Katz said. Dublin said he was planning to retire soon, so there was no incentive to get instrument qualified.

Safari Helicopters said it is a family-owned and operated business that opened in 1987.

The helicopter involved in the fatal crash was manufactured in 1998. The aircraft was involved in a 2001 accident the NTSB blamed on faulty manufacturing of its collective lock design, which caused it to inadvertently lift off during a test.

Katz said it is unlikely the flaw had anything to do with Thursday’s crash since it was repaired and would have revealed itself a long time ago.