The crew of downed Delta Flight 1141 called out that the jet's wing flaps were in the proper position for takeoff, according to cockpit recordings released Friday, adding more confusion to the crash investigation.

National Transportation Safety Board member Lee Dickinson said at a briefing Friday night that the statements captured by the flight recorder seem to disagree with physical evidence found at the scene of Wednesday's accident, in which 13 people died.Dickinson said the recording clearly indicates someone making a pre-takeoff call out for flaps and someone responding "15, 15. Green light." He said that would seem to indicate both flaps were shown to be in a matching angle of 15 degrees downward, a normal takeoff position for a Boeing 727.

Flight engineer Steven Judd also told the NTSB team Friday that he also heard the crew's first officer say "15, 15."

Flaps help provide the lift a plane needs to become airborne. The Delta jetliner crashed as it tried to take off from Dallas-Fort Worth International Airport.

Investigators say the flaps in the wreckage appeared to be in the up position. The Boeing 727 flaps have "physical locking devices" that would have prevented them from being knocked far out of place by a crash, said Bernard Loeb, deputy director of investigations for the NTSB.

Officials said they have not determined which voices belong to the specific crew members.

Another inconsistency investigators noted was no visible sign of damage to any of the plane's three engines. Dickinson said they will have to wait until the Pratt & Whitney power plants are torn down at the factory in Hartford, Conn., to learn more.

Judd told investigators all three engines appeared to be operating normally up until the time the nose wheel was lifting off 8,500 to 9,000 feet down Runway 18L.

Judd also said the right wing "dipped severely" after takeoff, and Capt. Larry Davis tried to correct the situation.

Earlier, an unopened emergency exit door where the bodies of many of the victims were found was prodded and photographed by investigators, who swarmed inside and out of the blackened wreckage.

Ninety-five of the 108 people on board survived, most by scrambling out of huge holes in the jet, which broke apart and burst into flames as it plowed into a field of sunflowers at the end of the runway.