LEXINGTON, Ky. (AP) – The taxi route for commercial jets at Blue Grass Airport was altered a week before Comair Flight 5191 took the wrong runway and crashed, killing all but one of the 50 people aboard, the airport’s director said Monday.

Both the old and new taxiways cross over the shorter general aviation runway where the commuter jet tried to take off early Sunday, Airport Executive Director Michael Gobb told The Associated Press.

The two runways form and X. The main strip, Runway 22, is 7,000 feet long; the shorter one, Runway 26, is only 3,500 feet. Aviation experts say the CRJ-100 would have needed 5,000 feet to fully get off the ground.

The runway repaving that changed the taxi route was completed late on the previous Sunday, one week before the crash, Gobb said.

It wasn’t clear if the Comair pilots aboard Flight 5191 had been to the airport since the changes. Comair operates that regular 6 a.m. Sunday flight to Atlanta from Lexington, but another commuter airline takes over the early morning commute during the week.

“It’s slightly different than it used to be,” Charlie Monette, president of Aero-Tech flight school based at the Lexington airport, said of the changes. “Could there have been some confusion associated with that? That’s certainly a possibility.”

The National Transportation Safety Board is investigating the crash and said it was reviewing runway and taxiway markings as part of its investigation.

Recorded conversations between the plane’s cockpit and the single person staffing the control tower in the minutes before Sunday’s crash showed no signs of anything wrong. The only runway mentioned was the main commercial strip, Runway 22, said NTSB member Debbie Hersman.

Somehow, the commuter jet ended up on Runway 26 instead _ a cracked surface meant for small planes that was much too short for Comair’s twin-engine jet.

What followed was the worst U.S. plane disaster since 2001.

“The take-off began, and the aircraft continued to accelerate until the recording stopped,” Hersman said.

The plane clipped trees, then quickly crashed in a field and burst into flames, killing everyone aboard but a critically injured co-pilot who was pulled from the cracked cockpit.

Information retrieved from the cockpit voice recorder indicated that the preflight preparations had been “consistent with normal operations,” Hersman said Monday.

There were no obvious problem with the airworthiness of the plane and the engines were in tact and appeared to have been in good working order, she said.

“Air traffic control and the flight crew planned for a takeoff from runway 22,” Hersman said. But “The F.D.R. (flight data recorder) and the evidence on scene indicates the crew took off from Runway 26.”

Hersman said the NTSB was interviewing the controller on duty at the time, reviewing records and transcribing the data and voice recorders retrieved from the crash.

Monday afternoon, they planned to use a high-riding truck to try to get the same view of the runway and airport layout that the pilots of Comair Flight 5191 would have had Sunday morning, she said.

She said they planned to conduct the same test on Tuesday at 6 a.m., the time of the crash to “try to see what the pilot saw.”

The plane’s two pilots were familiar with the twin-engine CRJ-100, and that plane in particular, the plane’s maintenance was up to date, and it wasn’t an old aircraft, Comair President Don Bornhorst said. Comair, based in Erlanger, Ky., is a subsidiary of Atlanta-based Delta Air Lines Inc.

“We are absolutely, totally committed to doing everything humanly possible to determine the cause of this accident,” Bornhorst said Sunday.

Hersman said the NTSB would also be looking at the weight of the aircraft, the runway available and where the plane should have been. A light rain was also falling Sunday, and it was still dark just after 6 a.m.

“We certainly are going to be looking at how to prevent something like this from occurring in the future,” she said.

At Blue Grass Airport, flights were back to normal Monday. The daily 6 a.m. Lexington-to-Atlanta flight took off safely, though with a different flight number, Delta 6107.

“Obviously there is some anxiety when something like this happens, but it is not something that would stop me from going,” said Mark Carroll, 47, a computer consultant from Lexington who was boarding the flight to Atlanta. “Things happen when you get older, it happens to everyone. You keep doing what you’re doing.”

The wreckage of Flight 5191, meanwhile, remained largely intact but severely burned in a field about a mile away.

The burned bodies of the 49 victims were removed from the plane on Sunday and taken to the state Medical Examiner’s Office in Frankfort for autopsies to determine the cause of death. Fayette County Coroner Gary Ginn said Sunday that they likely died in the fire.

The victims included a newlywed couple starting their honeymoon, a director of Habitat for Humanity International, an owner of a thoroughbred horse farm, a University of Kentucky official and a Florida man who had caught an early flight home to be with his children.

Amid the devastation and lost lives, there was also a story of heroism: Police Officer Bryan Jared reached into the broken cockpit and pulled out James M. Polehinke, the plane’s first officer, burning his own arms to save the man. Polehinke was listed in critical condition at University of Kentucky Hospital.

The crash marks the end of what has been called the “safest period in aviation history” in the United States. There has not been a major crash since Nov. 12, 2001, when American Airlines Flight 587 plunged into a residential neighborhood in New York City, killing 265 people, including five on the ground.