LEXINGTON, Ky. -- Investigators in Lexington, Ky., say the pilots of a Comair jet that crashed Sunday on takeoff noticed there were no lights on the runway they mistakenly used. It was too short.

Images: Commuter Plane Crash

A National Transportation Safety Board official said the only survivor, the first officer, was piloting the plane. All 49 others on board were killed.

The safety official said the cockpit voice recorder shows the pilots were talking about the absence of lights on the runway, but they didn't report it to the control tower.

Investigators are looking into whether the runway lights or changes made to a taxiway during a repaving project a week ago confused the commuter jet's pilots.

One flight instructor who flies almost every day out of Lexington says he was confused by the redirected taxi route when he was with a student Friday taking off from the main runway.

NTSB: Pilot Cleared For Correct Runway

Cockpit recordings reveal that the pilot had been cleared to use the correct -- and longer -- runway.

The crash killed all but one of the 50 people on board. Only co-pilot James Polehinke survived. He was pulled from the wreckage by a local police officer.

The airport's director said the taxi route for commercial jets using the main runway at Blue Grass Airport was altered just a week ago. Both the old route and the new one cross over the shorter general-aviation runway -- the one that the jet used to try to take off Sunday.

The jet that crashed needs about 5,000 feet of runway to build up enough speed for takeoff. The general aviation runway in Lexington is about 1,500 shorter than that.

National Transportation Safety Board member Deborah Hersman said the crew and the control tower, in their pre-takeoff conversations, were talking about the correct runway, and it's still not clear how the plane ended up on the other one.

One expert said "ground scars" at the end of a runway show the pilot of the doomed flight was trying to pull up fast to get the jet airborne.

Crews will try to get a sense of what the pilot was seeing in the minutes before the crash, in hopes of finding out what might have caused the confusion. To do so, they will ride in a truck with the windows the same height as the airplane, Hersman said.

Hersman said there will also be an investigation to determine if any of the crew members had consumed alcohol or had taken illicit drugs.

A police officer who rushed to the scene pulled out the plane's co-pilot. But the flames were too intense to save anyone else.

Comair President Don Bornhorst said Capt. Jeffery Clay had been a pilot with Comair for seven years and was very familiar with the aircraft.

Bornhorst also said the jet was purchased new in January 2001 and had up-to-date, clean maintenance records.

The crash marks the end of what has been called the "safest period in aviation history." There hasn't been a major plane crash since November 12, 2001, when American Airlines Flight 587 plunged into a residential neighborhood in Queens, N.Y., killing 265 people.

Victims Came From All Walks Of Life

The 50 people aboard Comair Flight 5191 Sunday morning were expecting a routine flight to Atlanta.

Among the dead were a newlywed couple, a Habitat for Humanity board member and a businessman heading home to his children.

Newlyweds Scarlett Parsley and former University of Kentucky baseball player Jon Hooker, 27, were leaving on a honeymoon trip to California. They were married the night before in front of 300 friends and family members.

"It's so tragic because he was so happy last night," said former Kentucky baseball coach Keith Madison, who attended the wedding.

Passenger Charles Lykins of Naples, Fla., had caught the early flight hoping to get home to his two young children after visiting friends and family in the Lexington area.

Pat Smith, a board member of Habitat for Humanity, was on his way to rebuild houses in Mississippi.

Passenger Jeff Williams, 49, was a horse trainer who won 13 stakes races at River Downs in Cincinnati, track spokesman John Engelhardt said. Williams had been working at a training center in Lexington.

Larry Turner of Lexington, also aboard the plane, was the chief officer overseeing the University of Kentucky's extension service, according to a statement from the university.

Mike Finley, 52, who lived in Corbin and owned the Finley Fun Centers, was headed to Reno, Nev., for a roller-skating convention, said his son, David Taylor.

"I'd say there's thousands of kids who grew up with our father," Taylor said.

Heroic Rescue Made By Officer

A police officer who reached the flaming wreckage of the passenger jet that crashed on takeoff in Kentucky Sunday morning burned his arms as he pulled the plane's co-pilot, James Polehinke, from the broken cockpit.

Officials said because of the fire, he was unable to reach anyone else.

Lexington police Officer Bryan Jared and two airport officers reached the wreckage of Comair Flight 5191 within minutes of the crash, which occurred a short distance from the runway.

Polehinke is in critical condition at University of Kentucky Hospital, where he was taken for lifesaving surgery.

Runway Mistakes Rare, But Have Happened

It's rare for a plane to get on the wrong runway but it's happened before -- with fatal consequences.

In 2000, a Los Angeles-bound Singapore Airlines jumbo jet mistakenly went down a runway at an airport in Taiwan that had been closed for repairs after a typhoon.

The jet slammed into construction equipment, and 83 people were killed.

An aerospace professor at Saint Louis University said, "Sometimes with the intersecting runways, pilots go down the wrong one."

At the Lexington airport, there was a light rain Sunday, and the strip veers off at a V from the main runway, which had just been repaved last week.

The shorter runway is 3,500 feet and has less lighting than the one designed for commercial jets.