Federal Aviation Administration officials are still investigating the cause of an incident that resulted in the crashes of two aircraft Tuesday at the Ames municipal airport.

Sandra Cambell, public relations officer for the FAA’s central region, said the FAA will not be able to release a report of the incident for about two weeks and that the National Transportation Safety Board will take even longer to determine the probable cause of the crash.

Early Tuesday afternoon, a small one-engine plane piloted by 69-year-old Charles Fullhart, of Ames, was taking off at the Ames Airport while towing a glider piloted by 69-year-old Abe Epstein, also of Ames.

Preliminary investigation of the crash indicates that the glider assumed an “abnormal position” on takeoff. The tail end of the glider struck the ground, as did the tip of the left wing, Campbell said.

The tow plane spun around 180 degrees in the air, causing it to lose lift and crash from a height of about 60 feet, she added.

The glider landed upside down about 25 yards off the end of the runway. The plane crashed into a field about 250 yards from the end of the runway.

Fullhart was able to escape from the plane before it was engulfed in flames. At press time Wednesday, he was still in Mary Greeley Medical Center for observation, Public Relations Specialist Bill Nutty said. Fullhart had suffered minor burns and other injuries.

Epstein was able to crawl from the shattered canopy of the glider, but was taken to Iowa Methodist Medical Center with neck injuries and cuts, Ames Public Relations Director Pam Reinig said. At press time Wednesday, he was still a patient there, listed in serious condition.

Campbell said the investigation will center on whether the glider’s abnormal position caused the crash or if the position was a result of some other force.

When a plane pulls a glider into the air, either pilot can release the tow rope at any time.

Campbell said that Epstein had released the tow rope, but not in time to prevent the crash.

The crash site has been cleared of debris, but the investigation has only begun. FAA investigators in Des Moines said they are still conducting interviews.

Aaron DeMoss, a mechanic at the airfield, was working in a shop a short distance from the crash site when the crash occurred. He said that everyone in the shop heard the tow plane’s engine quit, quickly followed by “a big thump.”

He said the mechanics ran out of the shop, some with fire extinguishersto help the two pilots.

“The fire extinguishers didn’t help much,” DeMoss said. When the fabric covering of the plane and the fuel that escaped the ruptured fuel tanks ignited, the plane was quickly destroyed.

Pilot Tom Dunham said he was flying in a plane about 700 feet above the crash site when he saw the tow plane hit the ground and “cartwheel twice.”

“I thought they were dead,” Dunham said.

Hap Westbrook, owner of Hap’s Air Service at the airport, was in the plane with Dunham. He said they quickly landed the plane and ran to help the downed pilots.

Westbrook said the low altitude and speed at which the crash occurred would not “give you much time to stabilize a tow plane” before a crash.

It could take a year before the transportation safety board closes the case on the crash, Campbell said.