Safety board releases preliminary report on Iowa plane crash
Francis Allegretti, 64, of Cambridge; Thomas Boos, 60, of Fort Atkinson; and Malcolm McMillan, 65, of Milton were killed in the crash June 23.
Witnesses told the agency the plane was flying low and the engine quit, restarted and quit again after making the sputtering noises.
No potential cause can be ruled out entirely, said Keith Holloway, NTSB public affairs officer.
Witnesses told Iowa newspapers that it was cloudy and gusty when the plane crashed, but the agency's preliminary report notes witnesses said skies were clear and "the weather was light and variable."
Investigations can take 12 to 18 months to complete. All the witness accounts and other evidence including medical and maintenance records are analyzed after the preliminary phase, Holloway said.
"We try not to do too much piecemeal work," he said. "We do the preliminary report once the on-scene work has been concluded to give an overview and will probably release a larger volume of information as we continue with the investigation."
Allegretti was found in the pilot's seat of the plane, Jerome Goodger of Milton previously told the Gazette. Goodger co-owned the plane with McMillan.
The three men were on their way to South Dakota for a hunting trip when the 1968 single-engine Piper 28 went down, family members told the Gazette.