Horrified Air Canada passengers started praying as its pilot suffered an apparent seizure and the plane swerved violently before the flight was made an emergency landing at Boston Logan airport

Witness Rodney McDonald said it appeared the pilot on the flight, which was operated by Air Canada’s regional partner PAL Airlines, appeared to have a seizure after the plane left Newark, New Jersey, at 12:39 p.m. on Wednesday.

“The moment the plane swerved, I knew something was wrong because it was not turbulence,” McDonald told ABC News.

McDonald said he, his wife and two boys were among the 61 customers on board the flight bound for Halifax, Canada.

“The flight started swerving violently. It really felt like someone had jilted the controls and then it happened over and over again,” he added.

“And, you know, every thought goes through your mind, you start praying. My boys instantly started praying.”

The dad was initially separated from the rest of his family on the plane — a twin-turboprop de Havilland Dash 8-400 — before rushing to help the stricken captain, who had been dragged out of the cockpit by a flight attendant.

“Yeah, it was really horrifying,” McDonald said.

“I went back to sit with them and then realized that the pilot was out of control physically, not violently, like it was clear that he was not in control of his faculties and needed to be restrained.

“[We] worked to get him under control, it was a fairly strenuous 40 minutes of keeping him down and using as many seatbelts as we could to restrain his legs, arms and chest.”

Cops and airport officials received an alert at 1:40 p.m. and the plane landed at Boston Logan just before 2 p.m., according to FlightAware data.

“Pilot is incapacitated. Aircraft is being flown by the co-pilot,” Broadcastify audio, obtained by ABC, revealed.

Air traffic controllers at Boston Logan warned other pilots that its runway 27 would be out of action due to “an inbound emergency,” the Canadian Press reported.

“During the flight, the captain experienced a medical issue and was removed from the flight deck as per safety protocols,” Air Canada told The Post, without specifying the emergency.

“The first officer took control of the aircraft and diverted the flight to Boston, where it landed safely,” the company added.  

Ambulances swarmed the plane after it landed and the aircraft was towed to a gate.

The plane left Boston Logan at 7:30 p.m. Wednesday and landed in Halifax just before 9:30 p.m. local time.

No further details about the pilot’s condition have been released.