Investigators yesterday started piecing together the final moments before a Coast Guard helicopter went down in waters five miles off Honolulu Airport Thursday night — killing three crew members and triggering a massive search for the fourth — and said the only apparent problem happened when the line that lowers the rescue basket seemed to malfunction.

Officials also said they received a distress signal from a Coast Guard 47-foot vessel that was participating in training with the helicopter at least two minutes before the aircraft hit the water at 8:15 p.m.

It's unclear, however, whether the problem with the line contributed to the crash, officials said, while stressing that the search for the fourth crewmember remains their top priority.

A Coast Guard helicopter and C-130, three Coast Guard boats, a Navy tugboat and divers, four boats from other state and city agencies and a Honolulu Fire Department helicopter combed a 10-mile-wide-by-13-mile-long search area through the night for the missing crewmember, who was identified as the pilot of the helicopter. Officials did not say whether the pilot or co-pilot was flying the aircraft.

Search conditions yesterday were described as ideal, with light winds and small swells.

Officials said the search will continue today. The 378-foot patrol boat Rush has been recalled from a law enforcement trip to American Samoa to assist. The Rush carries an HH-65 Dolphin, which will join the effort.

Today's search again will include HFD equipment and personnel, the Coast Guard said.

The Coast Guard yesterday identified the crewmembers killed in the crash as co-pilot Lt. Cmdr. Andrew Wischmeier, 44, of Fort Lauderdale, Fla.; rescue swimmer Petty Officer 1st Class David Skimin, 38, of San Bernardino, Calif.; and flight mechanic Petty Officer 2nd Class Joshua Nichols, 27, of Gloucester, Va.

The crash — the first of a Coast Guard helicopter in the Islands since 1982 — threw the relatively small, tight-knit Coast Guard community locally and nationally into mourning and spurred an outpouring of support from residents, lawmakers and others in the military.

"Losing a fellow Coastie is like losing a child," said Coast Guard Rear Adm. Manson Brown, commander of Coast Guard sector Honolulu, who added that he had never suffered a direct operational loss during his 30 years of Coast Guard service.

"Know that we have thrown the cloak of comfort ... over these families" of the victims, he added.

There are just 40,000 Coast Guard members across the country, about 1,400 of whom are stationed in the Islands.

At Coast Guard Air Station Barbers Point yesterday, "the whole airport just seems sad," said Brad Hayes, director of the Hawai'i Museum of Flying at Kalaeloa Airport, which sits next to the Coast Guard station.

"To lose an entire crew, Coast Guard-wide everyone's feeling the hurt," said Hayes, a former Marine corporal. "But this station is really feeling some pain. This is a huge thing for them, just gigantic. The Coast Guard is not used to losing Coasties on the scale of an entire crew."

DEBRIS RECOVERED

In addition to searching for the missing crewmember yesterday, Coast Guard and fire crews throughout the day recovered debris from the search area. The helicopter crashed in 1,600-foot-deep waters south of Honolulu Airport.

The fuselage of the HH-65 Dolphin helicopter was found partially submerged at the crash site Thursday night, and a tug boat towed it to just outside of Pearl Harbor, a Coast Guard spokeswoman said.

It was brought into Pearl Harbor yesterday.

The helicopter crashed minutes after it had completed a routine training mission.

The Coast Guard said weather conditions at the time of the crash were mild, the crew was experienced and there were no previous maintenance issues with the helicopter that went down.

"If you ask me today, how did this happen, the answer is I don't know," Brown said.

He said it's unclear what happened with the line that lowers the rescue basket. But he described it as "some issue."

Brown said the helicopter was participating in a search-and-rescue training mission.

Those are conducted up to three times a week in Hawai'i — and daily across the country.

Petty Officer 3rd Class Angela Henderson, Coast Guard spokeswoman, said before any training or rescue mission, Coast Guard crews assess the safety of a flight to pinpoint potential risks. The conditions considered include the weather, maintenance issues with a helicopter and the stamina of the flight crew.

If the risk is too high "we could possibly not go out," Henderson said yesterday. She did not have information on the assessment that was conducted on the flight that went down, but said the helicopter involved did not have any maintenance issues and the flight members were a "senior crew."

Coast Guard officials yesterday could not say when the helicopter took off Thursday from Coast Guard Air Station Barbers Point, but did say the training mission would have lasted about an hour and the crew was on its way back when the helicopter crashed.

Henderson said the helicopter was about two miles from the initial scene of the search-and-rescue training mission when it crashed. Two minutes before the helicopter went down, Henderson said, a distress call was made by the Coast Guard vessel the HH-65 was training with. Brown said the crew of the vessel had not yet been interviewed for the formal investigation, but will be in the coming days.

TRAINING DRILLS

The crash happened after the helicopter crew had finished conducting "small boat hoist" drills with a 47-foot Coast Guard vessel.

Henderson said the training involves lowering a rescue swimmer and basket down to the boat, then pulling up a victim in the basket, and finally pulling up the rescue swimmer.

All four crewmembers were back in place when the helicopter turned back to return to Kalaeloa.

After the helicopter went down, an Air Force C-17 preparing to land at Honolulu Airport instead circled the crash site until a Honolulu Fire Department rescue boat could get there. Coast Guard air and sea crews were also deployed to look for the helicopter flight members Thursday night and again through the day yesterday.

Brown said nothing in the fuselage that was recovered shed light on what happened to the fourth crewmember or whether he had any survival gear with him.

Staff writer Dan Nakaso contributed to this report.