The National Transportation Safety Board and the Federal Aviation Administration will investigate a powered-glider crash off Kauai yesterday that claimed two lives.

Two men died after the light sport aircraft plummeted into the ocean about 100 yards off Honopu Beach in Na Pali Coast State Park.

Positive identification has yet to be made on the victims, but people in the powered-glider community identified the pilot, or instructor, as Steve Sprague, owner of Kauai Aerosports. The other man was a student described as a visitor who has a wife and son. Kauai Aerosports, a flight school, declined to release information yesterday.

FAA spokesman Ian Gregor said operators of light sport aircraft cannot charge for passengers for tours, but that people can be charged for flight lessons.

The fatal crash was the third of a light sport aircraft — also known as powered gliders, microlights or trikes — in Hawaii in the past 14 months, and the second on Kauai this year.

The crash occurred at 10:53 a.m. yesterday. The Coast Guard launched an HH-65 Dolphin helicopter and a 47-foot motor lifeboat to help in the search. A tour boat discovered the bodies and the wreckage, according to Kauai County Fire Chief Robert Westman in a news release.

Gregor said the NTSB is making arrangements to recover the wreckage today.

Robert "Captain Sundown" Butler said he was aboard his sailing ship Kuuipo with crew members and passengers when he saw the powered glider with two passengers bank off a cliff.

Butler said he heard a pop like a rifle shot, then the aircraft went out of control and fell full speed into the ocean.

"He was going really fast. He didn’t have lift," Butler said.

Butler said his son Larry and a passenger dived into the water to see whether they could rescue anyone.

He said they were unable to pull the pilot and passenger from the aircraft immediately, so they tied a rope to the aircraft and the crew and passengers pulled up the wreckage.

Butler said his son and the passenger then cut the men free enough to bring them aboard.

The rope slipped, and the wreckage sank to the bottom again in about 20 to 25 feet of water, he said.

Butler said he has seen powered gliders buzz the cliffs.

On Feb. 15 a powered glider piloted by Jim Gaither, owner of Big Sky Kauai, crashed in the ocean off Kauai Coffee Co. in Kalaheo. The next day, divers recovered Gaither and 49-year-old passenger Kathy Buergel of Spokane, Wash., after an extensive search. Big Sky Kauai shut down sometime after the fatal crash, according to Denise Sanders, owner of Paradise Air, a powered-glider company on Oahu.

On April 21, 2010, two people died when a microlight aircraft crashed and sank in Kealakekua Bay on Hawaii island. The victims were pilot Tedd Robert Hecklin, 38, owner of Tedd’s Flying Adventures in Kailua-Kona, and passenger Kathryn Grace Moran, 37, of Kailua-Kona.

Sprague was the sole pilot at Kauai Aerosports, a flight school he and his wife, Anna, operated, according to their website at www.kauaiaerosports.com. Flight lesson rates are $235 for an hour and $345 for 90 minutes.

Sprague ran a hot air balloon business in Texas, said Gene Shoemaker, Sprague’s former father-in-law, from his home in San Antonio.

"To my knowledge he was a pretty good pilot," he said.

Sprague’s main business was flying and he also flew parasails.

"That was his love and his main occupation," Shoemaker said.

He recalled Sprague went to several competitions in Albuquerque, N.M., although he didn’t win. He last spoke with Sprague before he left for Hawaii about three or four years ago.

Shoemaker said Sprague has two adult daughters on the mainland and divorced about 10 years ago. He remarried and had at least another son with his wife in the islands, Shoemaker said.

Shoemaker had known Sprague since he was a boy in San Antonio. Shoemaker’s daughter was Sprague’s childhood sweetheart, and they married in their late teens or early 20s.

"He had a pleasant personality," Shoemaker said.

Star-Advertiser reporters Gary T. Kubota and Rob Shikina contributed to this report.