OWLS HEAD, Maine — The manager of the Knox County Regional Airport said Wednesday he will recommend a series of operational changes in the wake of a plane crash last month that claimed the lives of three young men.

Airport Manager Jeffrey Northgraves also said he is aware that private investigators have begun looking into circumstances of the Nov. 16 crash when the Cessna 172 collided with a pickup truck that was driving across the main runway. Northgraves said he is not sure who hired the investigators.

Northgraves met this week with the users of the airport to discuss a variety of issues, including who should be authorized to operate nonaircraft vehicles on airport grounds. He said he will present the recommendations Thursday afternoon to the airport advisory committee’s subcommittee on operations/safety and maintenance.

The manager said more than 100 people have been authorized by the airport to operate vehicles within the fences bordering the airport. Not all of those people have a need to cross or do cross either of the airport’s two runways — one 5,000 feet long and one 4,000 feet long, he said.

Training has already been required of people who operate within the fence but he wants to update that training by the end of the month, Northgraves said. He added that he would also recommend limiting the number of people authorized to cross the runways and increasing the level of training required of them.

There are hangars located on the other side of the main runway of the airport from the terminal but there is a separate parking area and separate access road for people using those hangars. He said those users have no reason to cross the runway.

Northgraves said he also will recommend that the airport study where vehicles are now allowed to cross the runways.

“The crossing [at the main runway] is probably located at the worst location,” he said.

That crossing spot is at about the 1,000 foot mark of the main 5,000-foot runway, which is where the accident happened.

“At that point you are pretty much committed to becoming airborne,” Northgraves said of aircraft.

He said a change in the crossing site would require construction of a road on the far side of the airport so vehicles can go near the end of the main runway and cross there.

Northgraves said he also will recommend that all vehicles that cross runways have a lighted beacon that must be used day or night.

The pickup truck involved in the Nov. 16 collision did not have a lighted beacon, as is recommended by the Federal Aviation Administration.

The crash claimed the lives of two University of Maine students and a UMaine alumnus. Killed were Lambda Chi Alpha Fraternity President David Cheney, 22, of Beverly, Mass; education officer Marcelo Rugini, 24, of Muliterno, Rio Grande do Sul, Brazil; and pilot William “BJ” Hannigan, 24, of South Portland, an engineering graduate student and member of the Maine Air National Guard.

The driver of the truck — Stephen Turner, 62, of Camden, has not returned several telephone calls or a written message for comment left for him at Penobscot Island Air where he works as a pilot and instructor.

Turner told police the incident happened so quickly he did not know if his truck and the plane had collided on the runway.

Local attorney Philip Cohen of Waldoboro acknowledged this week that he had been hired by a family of one of the victims, at this point to only gather information on the accident.

The National Transportation Safety Board is not expected to issue a final report on the crash for six months to a year.

According to a preliminary report filed a few days after the accident, however, Turner told the NTSB investigator that he announced over the common traffic advisory frequency for aircraft that he planned to cross the runway. He said he heard no response and didn’t see anything on the 5,000-foot-long Runway 31, so he proceeded to cross.

“He subsequently saw something grayish in color, continued to cross the runway, and then got out to inspect what he saw at which time he observed an airplane attempting to climb,” NTSB stated in its preliminary report. “He continued watching the airplane drift to the left of the runway and make a left turn as if attempting to return to the airport. Subsequently, the airplane was then observed in slow flight, and then it began to spin.”

The plane then went nose-down into the woods about 2,200 feet from where the truck and plane collided on the runway, according to the federal agency’s preliminary report.