An examination of the plane that crashed two weeks ago in a wooded marsh near Tara Field, killing two, "did not reveal any catastrophic in-flight mechanical failures," the National Transportation Safety Board says in a preliminary report.

But the NTSB said it's  retaining the wreckage of the March 8 crash for further inspection.

The agency quoted a witness who saw the twin-engine DeHavilland go down.

"He stated the airplane's engine noise was fluctuating from low to high, without stopping completely. He further stated the airplane was 'struggling to gain altitude and airspeed.' As the airplane turned to line up with the runway, it 'stalled' and descended nose first toward the ground."

The crash killed both people aboard, 37-year-old pilot Bryan Hedrick of Roswell and 48-year-old Oriel Roberts of Hampton. The aircraft was used for skydiving.

The NTSB quoted witnesses saying the fatal flight was the first since both of the airplane's engines were replaced. A mechanic told the NTSB he saw the pilot conduct pre-takeoff engine and propeller checks and witnessed the plane conduct two uneventful touch-and-go landings.

Hedrick reported about 900 hours of total flight experience, according to the report.