PITTSFIELD – The continuing investigation into a plane crash more than a year ago at the Pittsfield Municipal Airport, which claimed two lives, has revealed that water was found in the plane’s carburetor.

The crash, which occurred on June 12, 2003, took the lives of the airport’s operator, Ron Curtis, and a student pilot, Charles B. Brantner of Winterport.

Water contamination in Cessna aircraft is something pilots, including the Cessna Pilots Association and the safety program manager for the Federal Aviation Administration, have been investigating for years.

According to new information posted Thursday on the National Transportation Safety Board’s crash investigation Web site, fuel samples from the carburetor bowl and the fuel screen of the plane, which was owned and piloted by Brantner, were forwarded to a chemical analysis laboratory in Chicago for examination.

“According to a representative of the laboratory, the fuel sample contained water, copper sediments, and varnish. The fuel sample was consistent with ‘old fuel.’ Residue, observed in the fuel screen, was consistent with grease,” the report said.

A NTSB representative said Thursday afternoon that this was not the final report and was simply additional information that will be used eventually to determine a probable cause for the crash.

The report states that these components should have been checked as part of the Cessna 150H’s 100-hour inspection, which took place in April 2003, and that the fuel pumps checked at the municipal airport were clear and not contaminated.

Robert E. Skovill Jr. of Murfreesboro, Tenn., is a pilot and aircraft owner who monitors Cessna crashes and their causes after experiencing three total engine failures with his own Cessna 172P. He maintains a Web site that warns Cessna pilots that a possible design flaw in the Cessna fuel tanks allows water to collect and go undetected in routine preflight checks.

“When I first learned of this Pittsfield crash more than a year ago, I predicted that water in the fuel would be the problem,” Skovill said Thursday afternoon. “What is important here is: Would those men have taken off and flown if they knew they had water in their fuel tanks? Of course not. But because of the design of the Cessna tanks, the water goes undetected in a preflight check.”

In 1999, Skovill conducted a water experiment on his own aircraft and on a Cessna 150 and 152. Despite deliberately pouring 104 ounces of water into his fuel tank, no water was detected when Skovill checked all 10 sump drains. He has since grounded his Cessna aircraft.

“Lives are being lost almost daily,” said Skovill, who noted NTSB investigators “habitually blame the pilot for a poor preflight check.”

The NTSB report said a witness who was working in a nearby hangar heard the aircraft’s engine “skip,” which made him look up and observe the airplane in a steep left turn. The witness observed the tail swing aggressively to the right, and at the same time, he heard the engine rev up.

The airplane then stalled, and began to spiral downward counterclockwise, before hitting the asphalt and bursting into flames.

The report does not identify the witness, but several people were at the airport and saw the crash occur, including a local police officer and several Pittsfield highway workers.

The report also indicated that Brantner, who was piloting the plane and practicing touch-and-go landing techniques, might have failed to follow standard procedures for landing a plane in distress.

Included in the NTSB report is a paragraph from the FAA Airplane Flying Handbook which states, “If an actual engine failure should occur immediately after takeoff and before a safe maneuvering altitude is attained, it is usually inadvisable to attempt to turn back to the field from where the takeoff was made. Instead, it is safer to immediately establish the proper glide attitude, and select a field directly ahead or slightly to either side of the takeoff path.”

In the fatal crash, witnesses said the plane at first turned back toward the runway and then spiraled into the ground.