DENVER -- The cockpit data recorder aboard the charter jet that crashed Sunday in Montrose "is of a good recording quality," a National Transportation Safety Board investigator said Tuesday afternoon.

Arnold Scott said the cockpit recording is 31 minutes long and begins while the aircraft is on the ground and preparing for departure. The recording "captures the entire accident sequence including the takeoff and subsequent accident," said Scott.

He said he would not release further information because investigators want to make sure they didn't miss anything and to protect the integrity of the crash investigation.

Investigators also said Tuesday that the plane was not de-iced before it went down, killing NBC sports executive Dick Ebersol's youngest son and two other people. Investigators have not ruled out other possible factors.

The twin-engine Challenger CL-601 crashed and exploded Sunday morning, killing the pilot and a flight attendant and injuring Ebersol and one of his sons. Another son, Edward "Teddy" Ebersol, 14 died in the crash.

The Montrose County coroner said Tuesday that Edward Ebersol died instantly after he was thrown from the aircraft and the plane landed on top of him. His body was recovered from underneath the charred fuselage of the jet on Monday afternoon. Coroner Mark Young said no autopsy was conducted on Ebersol.

Ebersol and the couple's oldest son, Charlie, remained hospitalized but are expected to recover, NBC said.

The co-pilot, identified by Denver newspapers as Eric Wicksell of Daytona Beach, Fla., was in critical condition at a burn unit in Denver.

The pilot and a flight attendant who died were identified as Luis Alberto Polanco, 50, recently of the Dominican Republic, and Warren Richardson III, 36, of Coral Gables, Fla.

A snowstorm had eased up before the plane prepared to take off, but it has not been determined if weather was a factor in the crash or whether the plane had ice on the wings.

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Look At Crash Photos Listen To 911 Calls About The Plane Crash

"We do want to look at de-icing because of the weather conditions but we're not going to just focus on one possibility," said Ellen Engleman Connors, chairman of the National Transportation Safety Board.

Connors said that among the factors to be studied are "structural failure, fuel imbalance, engine failure, was there a problem with air speed, human factors" and weather. Investigators will interview Ebersol when doctors allow it, she said.

A Denver-based expert said ice should not have made a difference.

"That (plane) is so overpowered that the weight of the ice can't stop it from taking off," said Dave Kempa, president of Air Denver, a referral service that matches charter jet operators with passengers.

Scott also said the plane was capable of flying while its wings were iced.

Steve McLaughlin of MTJ Air Services, which deices private planes at the airport, said MTJ did not deice Ebersol's plane before it took off. Airport Manager Scott Brownlee said at least one commercial jet had deiced before taking off Sunday.

Federal Aviation Administration rules bar aircraft from taking off with ice or snow on the wings or some other surfaces. Ice can make a plane too heavy to fly and can also affect its aerodynamics.

"It's a double whammy," Kempa said.

Plane Used Shorter Runway For Takeoff

The plane also took off on the shorter of two runways at the airport, something that puzzled some onlookers, but Scott said the plane had landed on that runway earlier.

"If they had the long runway available, why take the short one?” asked Scott Bordon, a Civil Air Patrol pilot. "It's almost as if they got on it not realizing it was the shorter runway."

The jet took off on the 7,500-foot runway even though the 10,000-foot runway was available and nearby.

According to Scott, the pilot asked for the longer runway, but it was being plowed, and the plane used the shorter runway, even though the snowplow moved to the side. The snowplow operator said he watched the jet waiting and then saw it take off on the shorter runway.

Scott said the takeoff was more of a "skipping" takeoff, with the plane coming back down several times before the crash. He determined this by examining skid marks on the ground.

"If it was airborne for any length of time, tt wasn't for any prolonged length of time," Scott said. The plane then skidded on its belly, but did not cartwheel.

On Sunday, callers to the 911 communications center in Montrose told the dispatcher that the plane just "blew up" and "exploded."

One caller told the dispatcher, "I see the airport and it looks like an airplane just crashed. There's like flames."

Doug Percival heard the crash and ran from the office of the towing company where he works. He said Charlie pleaded for him to rescue his kid brother, and Dick Ebersol sat nearby on the snowy ground amid the billowing smoke, numbly rocking back and forth.

"You could tell he was in shock. Both of them had been ripped out of their shoes," Percival said.

Montrose County sheriff's Deputy Shane Schmalz arrived at the crash site less than two minutes after the accident, as flames engulfed the wreckage.

Charlie Ebersol saw him and also begged Schmalz to save his brother, but flames beat would-be rescuers back.

Schmalz told Dick Ebersol to hang onto his shoulders, and the deputy carried him away from the flaming wreckage, according to Undersheriff Dick Deines.

Sgt. Richard DeWeber arrived shortly after Schmalz. Charlie Ebersol used DeWeber's cell phone to call family members. DeWeber helped Dick Ebersol into a pickup truck where he laid down, holding his arms over his chest and shaking violently. He had complained of back pain as well.

Dick Ebersol asked DeWeber to call Ebersol's wife and tell her about the crash.

The Ebersol family issued a statement Tuesday that said, "Dick and his son Charlie are hospitalized in good condition and (are) expected to make a full recovery." Read the Ebersol statement on Charlie.

The Ebersols are currently hospitalized at St. Mary's Hospital in Grand Junction.

The Montrose airport is one of several that serves Telluride, a popular ski destination for celebrities.

The plane landed in Montrose after a flight from Van Nuys, Calif. to drop off Ebersol's wife, actress Susan Saint James. The Ebersols have a home near the Telluride ski resort. Saint James, who starred in the 1980s television series "Kate and Allie" and "McMillan And Wife," was not on board. The plane was headed to Notre Dame, Indiana, where Charlie attends college.

Teddy Ebersol was remembered by classmates at the Gunnery Boarding School in Connecticut as a leader in the dormitory where he lived, and was a warm and friendly person.

Polanco, the pilot of the ill-fated jet, was a 20-year veteran with more than 12,000 hours total flying time and more than 900 hours in a Challenger aircraft. He had a valid Dominican pilot's license, which he first obtained in 1977, said Francis Mesa, a spokesman for Dominican Civil Aeronautics. Polanco also was licensed to fly in the United States and planned to move his family to New Jersey, where Jet Alliance is based.

Leandro Polanco, 18, said his father was an excellent pilot.

"I always felt safe with him," he said Tuesday from his parents' home in Santo Domingo. "I want to study aviation like him," he said.