A small plane was forced to make an emergency landing Monday on the beach at Robert Moses State Park.

The Cessna 172S was carrying a pilot and two 16-year-old students on an instructional flight when it landed at Field 2. State park officials say everyone was able to get out safely, and the beach was mostly empty at the time.

The plane flipped over on the sand after it landed.

Steve Fratelolo was on his morning walk along the beach and saw the incident unfold.

"I heard a plane and it sounded pretty low," he recalls. A former navigator aboard a B-52 bomber, Fratelolo says he knew there was trouble. He watched the plane struggle to land on the beach.

"They came in level, but the nature of the sand made the nose dip, and when the nose dipped the nose hit the sand and they flipped over," Fratelolo says.

Flight data shows the plane left Republic Airport in Farmingdale just before 9 a.m. and headed south toward the beach.

State park officials say they indicated that they had some sort of mechanical issue. An exact cause hasn't been determined,  but the FAA is now investigating the incident.

According to the tail number of the plane, it is used as a trainer by Nassau Flyers, a flight training company at Republic Airport. It had no comment about the emergency landing.