But they never made it.

Shortly after taking off from the Julian Carroll Airport in dense fog here late Monday night, the University of Kentucky helicopter ambulance slammed into a Breathitt County hillside.

All four crew members were killed. No patients were on board.

No cause had been determined yesterday. The investigation will continue today, but it could be months before authorities know the cause.

Officials said the craft disintegrated as it hit the woods, then exploded into flames.

``It was pretty bad,'' said David Jones, veteran administrator of the state medical examiner's office. ``It was one of the worst I've seen.''

Petroleum Helicopters Inc. of Lafayette, La., which leased the Sikorsky S-76A helicopter to UK, identified the two pilots as Don Green of the Lexington area and Ernie Jones of Cleveland.

Also on board were Sheila Zellers, 43, of Elizabethtown, a veteran UK flight nurse, and paramedic Brian Harden, 31, of Richmond.

The medical examiner's office and other agencies would not release the names of the victims, pending autopsies and other efforts to identify them.

News of the crash spread shock and dismay yesterday among staffers and faculty members at UK's Chandler Medical Center.

``We've lost four people who were good friends, good professional friends, good personal friends. We've lost four people who made a difference in the lives of hundreds of human beings,'' said Medical Center Chancellor James Holsinger.

The helicopter ambulance, one of two operated by UK, normally flew to the Jackson airport each morning. It would spend the day operating from there, dispatched as needed to points around Eastern Kentucky, then return to UK each night after a 12-hour shift.

That system, which began in October, is designed to reduce flying times and save lives by getting patients to the hospital faster.

The helicopter flew to Jackson on Monday morning as usual, but received no flight calls during the day, Holsinger said. That was unusual, because the helicopter had made about 450 flights since it began operating out of Jackson. The craft was on its way back to Lexington when it crashed about 10:08 p.m.

Second crew grounded 

Flags flew at half-staff at UK yesterday. The medical center's one remaining helicopter ambulance was grounded for the day while crew members struggled to deal with their grief.

Holsinger said the helicopter might return to service today, but wouldn't fly unless crew members felt ready to resume service.

``If they're ready to fly, we'll fly,'' he said.

UK used its first helicopter ambulance in August 1987, and it continues to operate from the medical center in Lexington. Monday's crash was the first for UK, officials said.

The helicopters fly to hospitals in about a 400-mile radius from Lexington, transporting severely injured or ill patients. They sometimes also fly directly to remote accident scenes in places like the Red River Gorge.

The irony and sadness of losing people who worked to save lives was evident both at the crash site and in Lexington yesterday.

``They came when people needed them the most,'' said Stephen Bowling, a volunteer firefighter and editor of the Jackson Times, a local newspaper. ``They risked their lives to save people.''

Holsinger said crew members did their work enthusiastically, despite the hazards.

``They're really dedicated about what they do and the service they provide to people,'' he said. ``I suspect that they seldom if ever count the risk. Last night, we all learned that risk.''

Investigator Bob Hancock of the National Transportation Safety Board, assisted by the Federal Aviation Administration and others, began combing through the wreckage of the helicopter yesterday and will continue today.

It could take months to figure out the cause of the crash, however.

Hancock will investigate to determine whether the crash was caused by human error, mechanical problems, or environmental factors, such as weather and terrain, or some combination.

State police recovered the helicopter's cockpit voice recorder and sent it to Washington, D.C., for analysis, Hancock said.

Workers will begin trying today to move wreckage from the site, perhaps by helicopter, to a hangar where it can be better analyzed.

Jeff Ratliff, manager of the Jackson airport, saw the helicopter lift off for home about 10 p.m. Monday. He said it sounded normal.

At the time, fog was thick in the area following a heavy rain. Visibility was listed as one-quarter mile and 100 vertical feet, and the National Weather Service office at the airport had issued a dense fog advisory, said Mike Lewis, science and operations officer at the weather station.

The advisory is primarily for motorists because it describes ground conditions. It's not clear how thick the fog was 300 or 400 feet up, Lewis said.

Equipped to deal with fog 

However, UK officials said the helicopter was equipped for all weather conditions and should have been able to deal with the fog. They said pilots would have had the option of canceling the flight if they felt conditions were too hazardous. Also, the pilots had both flown in and out of the area before and were qualified to fly by instruments alone in fog.

They had filed an instrument-flight plan with air traffic controllers in Indianapolis, officials said. The temperature was 65 and the wind was calm at 10 p.m. Monday, Lewis said.

The helicopter apparently headed south, not north toward Lexington, after taking off. The reason was not clear yesterday, though Ratliff said the pilot may have been trying to go toward Hazard guided by a radio signal, then turn toward Lexington.

The helicopter appeared to travel a semicircle, and was headed back in the direction of the airport when it hit the hillside. The crash site was no more than 2 miles from the airport and the helicopter had been airborne a very short time.

Contact lost 

Hancock said he knew of no distress call before the crash. In fact, Ratliff said he did not hear the pilots contact UK flight control by radio, as was customary, and tried twice to call the helicopter by radio himself, but got no response.

``I started getting worried,'' Ratliff said.

According to UK's Holsinger, air traffic controllers in Indianapolis notified the university dispatcher that they had lost contact with the craft. The UK dispatcher then tried to contact the helicopter, but there was no answer.

By then, the helicopter had hit the side of a steep, wooded hill about 6.5 miles east and slightly south of Jackson. It appeared to be descending at a shallow angle of about 9 degrees, Hancock said.

Accounts of witnesses 

People who live near the site and heard the helicopter go over said it sounded lower and louder than usual.

``It didn't sound like it was flying right,'' said Mark McIntosh, 22, who lives near the crash site.

John Bach, a retired postal worker who lives close to the site, said he first thought a bulldozer was driving by his house.

``It was really loud and flying low,'' he said. ``It just kept getting louder and louder.''

Bobby Thomas, who also lives near the site, said the route the helicopter was flying was not the one it usually took at the end of the shift.

McIntosh said he went outside his mobile home to look at the helicopter and heard it crash into the hill a few hundred yards away.

He ran to his truck to call 911, and about 30 seconds after the crash heard an explosion and saw a fireball shoot up 50 feet.

He later ferried emergency workers to the site by all-terrain vehicle.

``The explosion was too tremendous'' for anyone to survive, he said. ``They was torn up pretty bad.''

Ratliff, near tears, said the pilots and crew of the helicopter were caring, careful professionals.

``They wouldn't have left if they didn't think they could make it,'' he said. ``As professional as they were, I just can't understand it. Something must have happened.''

UK stationed the air ambulance at the Jackson airport for a one-year trial, and area residents welcomed it, said Mike Johnson, director of the Life Care Ambulance service in Breathitt County.

The helicopter service has saved lives by cutting in half the time needed to get victims of heart attacks and car wrecks to Lexington, he said.

``It's made a big difference.''

The location 

A tree-covered, rocky mountainside bordered by Ky. 30 in Breathitt County, east of Jackson.

The four victims

• Don Green, pilot
• Ernie Jones, pilot
• Sheila Zellers, flight nurse
• Brian Harden, paramedic

They were Kentucky's first medical helicopter fatalities.

The helicopter 

A Sikorsky S-76A. The 52-foot-long helicopter, powered by two engines, had a maximum cruise speed of 145 knots and a maximum range of 475 nautical miles.

The investigation