Interviews with the hospitalized pilot of Delta Flight 1141, possibly as early as this week, might answer some nagging questions investigators have about the fiery crash that killed 13 people.

The National Transportation Safety Board Monday began moving its probe of the crash back to Washington, D.C., although a number of investigators remained near the charred wreckage of the jetliner.A NTSB spokesman at the agency's command post at Dallas-Fort Worth International Airport said much of the investigators' work has been finished.

"Some groups have left, but some of the teams remain out here because there is still work to be done here," said the spokesman, who asked that his name not be used.

The jetliner, carrying 108 people, crashed and broke apart during takeoff Wednesday morning at the airport, killing 13 people.

As of Monday, only 12 of the 95 survivors remained hospitalized from injuries received in the crash, but that includes the pilot, who the NTSB says holds key information about the events of the mishap.

Lee Dickinson, who coordinated the NTSB examination and conducted briefings for reporters, made his last appearance Sunday before joining those returning to Washington.

He said the pilot, Capt. Larry Davis, 48, of Greenville, Texas, likely would be well enough to be questioned in three to four days.

Davis, who suffered facial fractures and a back injury, was flying the plane at the time of the crash. The Air Line Pilots Association says Davis cannot be questioned while he is taking medication to relieve pain.

When able, he is expected to settle several questions that have nagged investigators, such as whether one or perhaps two of the Boeing 727-200's three engines failed and whether the wing flaps were in the proper positions throughout the attempted takeoff.

Investigators hope he will be well enough to be interviewed this week.