Friends are mourning the Oakdale couple killed Saturday in a small plane crash on the North Fork.

Southold police say 66-year-old Robert Mark was piloting the plane, and his girlfriend, Susan Quagliano, 57, was a passenger.

As News 12 has reported, the pair was killed when their small plane went down in a field at Harbes Farm in Mattituck shortly after 9 a.m.

Officials say the plane took off from MacArthur Airport and was headed to Massachusetts when the pilot radioed that he was having engine trouble.

No one on the ground was hurt in the crash. The FAA and NTSB are investigating.

Friends and fellow pilots gathered at MacArthur on Sunday to mourn the loss of their friends.

"It wasn't supposed to happen to Robert. If you ask any one of us here, we would consider ourselves lesser pilots than Robert," says friend Joe Waldman.

Waldman says he flew planes in formation with Robert Mark. He says Mark had flown planes for 30 years and was the best pilot he knew.

Friends say Mark and Quagliano were on their way to New Bedford, Massachusetts, to participate in a "missing man formation," a flight in honor of a missing pilot.

Quagliano, Mark's long-time girlfriend, was not a pilot, but loved flying with him, according to friends. The couple lived together in Oakdale.

"She was decorating her house, she was taking classes. Just enjoying life," says friend Michele Colavolpe. "She swam everyday, they had a pool."

Mark is being remembered as a selfless person, often volunteering to fly people in his own plane to get to doctor's appointments out of state.

The group of pilots who gathered Sunday plans to take to the skies again soon, to fly the way that Mark and Quagliano loved.

The couple's dog, Coco, was aboard the plane, but survived the crash. Friends tell News 12 that Coco has since been reunited with Mark's family.