DENVER, Nov. 18 -- A review of conversations in the cockpit of Continental Flight 1713 indicates that the less-experienced pilot, copilot Lee Bruecher, was flying the jet when it encountered trouble on takeoff and crashed Sunday at the Denver airport, a Continental official said tonight.

Bruecher, 26, a former commuter airline pilot who was making his second trip as a DC9 copilot, had accumulated only 36 1/2 hours flying time as a turbojet pilot. All of Bruecher's previous flying experience was on turboprop aircraft, and he had never been involved in any de-icing activity since joining the airline in July, investigators said.

An analysis of the plane's cockpit voice recorder indicates that the nonflight duties were being performed by Capt. Frank Zvonek, 43. One pilot usually performs nonflight duties such as calling out checklists while the other pilot flies the plane.

Investigators found today that both hand-holds on the yoke, which the pilots grasp like an automobile steering wheel, on Zvonek's side of the plane were broken in the crash, as were both of his arms. This could indicate that Zvonek may have been trying to regain control of the plane. Since becoming a DC9 captain in October, Zvonek also had not flown on any flights that required de-icing.

Both men died in the crash, which killed 28 of the 82 aboard and injured 54. The twin-engine DC9-10 crashed and rolled onto its back just after lifting off the ground Sunday.

Richard Hillman, Continental's vice president of flight operations, said that after listening to the cockpit voice recorder today, he is satisfied that Bruecher was flying the plane during takeoff.

"The decision as to who makes the takeoff is left to the captain," he said. It is "not unusual" for the captain to assign the copilot to pilot the aircraft on takeoff while the pilot monitors the overall operation, Hillman said.

Bruce Hicks, a Continental spokesman, discounted the attention focused on crew experience and cautioned against drawing "inferences that are not correct."

"These were extremely experienced pilots," he said, adding that examination of their experience on the DC9 alone gives a distorted picture of their qualifications.

Zvonek, who had 12,000 hours of flying experience, was certified as a DC9 captain 17 days before the crash, according to National Transportation Safety Board Chairman Jim Burnett. Bruecher, who had 3,200 hours of flying experience, had flown 36 hours and 36 minutes as a DC9 copilot.

Investigators also have concluded that the pilots failed to make a routine radio call to air traffic controllers when they pushed back from the boarding gate, an oversight that may have cost them critical minutes before they tried to take off in a heavy snowstorm.

Zvonek and Bruecher did not radio for a clearance before moving to Continental's de-icing pad, investigators for the safety board said.

As a result, controllers lost track of the plane as it moved to the de-icing pad and then to the runway, where it sat for up to 10 minutes while other planes were allowed to take off before it. Time sequences have become crucial to the investigation because investigators are trying to determine if the jet was delayed long enough after it was de-iced for ice to form again on its skin.

As the investigation entered its third day, four central issues emerged that, combined, could have led to the crash:

Weather: Investigators are measuring the water content in the snow and are trying to calculate how hard it was snowing to determine how quickly ice could form on the plane the afternoon of the accident. They also have interviewed several witnesses who told them they saw ice on the wings after the plane passed through Continental's de-icing pad. Burnett said one witness told the board that the snow was blowing so hard he could not see out of the window after the de-icing. Three passengers traveling together said the de-icing equipment made several passes on the jet's left side, but only one on the right.

Air traffic control: Federal regulations require all departing aircraft to contact air traffic controllers for a clearance before pushing back from the gate. In large, hub airports, aircraft are allowed to push back from the gate, but must contact controllers for a clearance to taxi from the airline's ramp area near the gate.

Sources said tonight that the DC9 apparently was in a "movement area," where other planes move around, and should have obtained a clearance from ground controllers in the tower.

At most airports, planes are de-iced at the gate. Continental installed its new state-of-the art de-icing pad in its ramp area last year. To be de-iced, its jets move from the gate to the pad, where a 190-degree mixture of glycol and water are poured over the plane with equipment that operates much like a movable carwash.

When the plane moved to the de-icing pad, controllers thought it was at the gate, according to crash investigators. When the crew radioed for permission to leave the de-icing pad, the controller apparently misunderstood where the jet was, because the controller gave the crew permission to taxi to the de-icing pad. The pilots apparently did not observe the controller's confusion, and taxied to the runway, where they sat in their jet waiting for the tower to call them and give them clearance to take off.

The controllers, meanwhile, were waiting for the plane to radio for permission to leave the de-icing pad.

In ordinary circumstances, such an oversight might have been caught. Controllers, confused about where the plane was, would have seen it from the control tower's window and corrected the miscommunication. But it was snowing hard, and they could not see the jet sitting at the end of the runway, investigators said.

Plane design: The 21-year-old jet is an early-model DC9, which does not have slats on the front edge of the wing. The manufacturer, Douglas Aircraft Corp., reminded operators of that model in late 1985 that the plane is susceptible to even small amounts of ice buildup when operated in winter conditions.

Crew experience: The captain, although a seasoned pilot, had flown in DC9s for only five months and had just been certified as captain 17 days before the crash.

Experts said the experience level of the crew in the DC9 becomes a crucial factor only when combined with the bad weather, the plane's tendency to accumulate ice and the confusion with air traffic controllers that caused the delay in taking off.

Both pilots met the minimum requirements for pilot certificates.

Zvonek's career at Continental characterizes the airline's troubled history in microcosm. Zvonek joined Continental as a flight engineer in 1969, with 1,400 hours of flight time as a Navy pilot. In 1977, he became a copilot and flew Boeing 727s until 1982. That year he reverted to flight engineer after the airline went through financial hard times and made cutbacks. In October 1983, Continental's pilots went out on a long strike that ultimately broke the pilot's union. Zvonek was off work for three years. He was rehired at the end of the strike in July 1986 as a flight engineer. Last April, he was certified on the DC9, which he flew as copilot until he was upgraded to captain Oct. 28.

According to Continental's payroll records, Bruecher made his first trip as a DC9 copilot in late October and flew a several-day assignment, accumulating 36 hours and 36 minutes of flight time.

He was hired by Continental July 20, after accumulating 3,150 hours piloting Beechcraft 1900s and Twin Otters, both turboprop planes, for Rio Airways of Texas.