Investigators were unable to find any clues to show an 82-year-old pilot had a medical problem before a plane crash that killed him, his wife and two Oklahoma State University coaches in November, according to autopsy reports obtained under an open records request.
The autopsy report for pilot Olin Branstetter, obtained in Arkansas by The Associated Press on behalf of The Oklahoman, stated Branstetter and the others aboard the plane died instantly in the crash.
The generally poor condition of Branstetter's body hindered the ability of medical examiners to determine whether Branstetter experienced a medical event, such as a heart attack or a stroke, before the crash.
Branstetter was piloting a 1964 Piper PA-28-180 Cherokee when it crashed Nov. 17 in the Ouachita National Forest in central Arkansas. Branstetter and his wife, Paula, 79, were killed in the crash, as were OSU women's basketball coach Kurt Budke and assistant coach Miranda Serna.
The two coaches were headed to Little Rock for a recruiting trip. The flight originated in Ponca City, where the Branstetters lived. It landed at Stillwater Regional Airport about 1:45 p.m. to pick up the two coaches. The flight took off from Stillwater at 2:45 p.m., according to a National Transportation Safety Board preliminary report.
The plane was flying southeast at 7,000 feet when it entered a right turn and started to descend, soon disappearing from radar, according to the report.
Charles P. Kokes, the chief medical examiner who performed Branstetter's autopsy, said the fact that Branstetter's body was badly fragmented from the impact made it difficult to find any definite answers.
“In the end, you're just putting together a lot of different puzzle pieces to just try to get the clearest possible picture,” Kokes said. “And in an instance like this, unfortunately, you're going to have far fewer available pieces.”
Branstetter's autopsy report lists his cause of death as multiple blunt force injuries. A Federal Aviation Administration toxicology report shows no drugs or ethanol were detected in Branstetter's muscle tissue.
Records show investigators didn't perform tests for cyanide or carbon monoxide poisoning. National Transportation Safety Board inspectors said it was impossible to perform those tests with the amount of tissue available.
National Transportation Safety Board investigator Jason Aguilera said officials have found no evidence Branstetter was affected by carbon monoxide poisoning, which can occur in some airplanes when exhaust fumes get into the cockpit from the plane's cabin heat system.
However, investigators found no problems with the plane's cabin heat system, Aguilera said, making it unlikely that exhaust fumes could have entered the cabin.
NTSB inspectors have said they have ruled out weather as a factor and have also said there's no indication the plane ran out of fuel before the crash. Inspectors have said it could be up to a year before a final NTSB report, including a cause of the crash, is available.
Branstetter, a former state senator, was an accomplished pilot and a licensed flight instructor.