An East Hampton resident, her daughter, their nanny and a pilot were killed in a plane crash Sunday afternoon.

Officials say real estate agent 49-year-old Adina Azarian and her 2-year-daughter Aria were on their way to MacArthur Airport in Ronkonkoma when the plane crashed in a rural part of southwest Virginia.

The Federal Aviation Administration says the group took off from Tennessee, turned around over Long Island and flew straight into restricted airspace over Washington D.C.

Aviation expert Dr. Michael Canders speculates that the plane was already on autopilot when it turned around near Long Island, and that “hypoxia” could have incapacitated the pilot and others on board. Hypoxia occurs when there is not enough oxygen in the cabin.

“We use these accidents to learn to make sure that we’re following procedures,” Canders says. “Aviation is very much about checklists and procedures, and the NTSB will look at if all the maintenance procedures were followed.”

Flight tracking sites showed the jet dropped rapidly at one point at a rate of more than 30,000 feet per minute before crashing.

Neighbors say Azarian was very friendly and would always say hello to everyone in the community.

“From her being pregnant and seeing the child, and now we’re just devastated,” says neighbor Marie Lombardi.

Azarian worked for Keller Williams. In a statement, the company described her as having “a vibrant personality and unwavering commitment to her clients that set her apart in the real estate industry.”