Preliminary report on plane that buzzed Colorado boaters questions flight instructor's account of mechanical issue

The National Transportation Safety Board has issued a preliminary report on a Sept. 11 incident that saw a Cessna 172 buzz some boaters on Horsetooth Reservoir before it crashed. The initial agency account is questioning the initial explanation provided by one of the two brothers on the plane. One of the men is a flight instructor, the second is a pilot.

Photos obtained by CBS News Colorado showed the small plane buzzed a boat on the reservoir just before the crash. A witness said the plane was nearly on top of the boat.

In the newly released report, the flight instructor said "an engine power issue had occurred. He stated that in an effort to avoid landing on the water or impacting boats on the surface, he elected to make a climbing right turn... away from the lake..."

The flight instructor said he and his brother were flying the plane "and his brother reduced power to 'observe more of the scenery.'''

Shortly after, the brother said "he could not climb due to a jammed elevator." The flight instructor said he took control of the plane and "the elevator was jammed and he used power and trim to climb." He said they attempted to free the jammed elevator by "wiggling the flight control in and out."

As the plane left the reservoir, it hit a tree. Both men survived the crash.

But the report notes that a Federal Aviation Administration air safety inspector examined the plane and "flight control continuity was established from the control yokes to the elevator control surface with no binding or mechanical anomalies noted." The report continues, "A visual examination of the other flight controls revealed no anomalies that would have precluded normal operation."

A more detailed exam of the aircraft is pending.

"It's not likely that it's going to fail, and if it did fail, then we would not expect to see the airplane maneuvering the way we saw it in the video," said Robert Katz, a commercial pilot and flight instructor who has been flying for 41 years.  

After reviewing the preliminary report, Katz said little appears to substantiate the sequence of events the men described.  

"If this was not deliberate, I would expect evidence, physical evidence in the airplane itself, that would corroborate and substantiate the story that's being told," Katz said. "On the face of it, at the moment, that does not appear to be the case."  

If this was found to be a deliberate act, the two men could face fines and a revocation of their pilot licenses for violating federal regulations, Katz told CBS News Colorado.

Authorities have not identified the two brothers who were on the plane.