UPDATED @3:30 p.m. 3/27/2012 with a statement from the FAA.

AMARILLO (CBSDFW.COM) — A JetBlue plane headed from New York to Las Vegas made an unscheduled landing in Amarillo Tuesday after the captain started acting erratically.

JetBlue flight 191 landed in Amarillo at 10 Tuesday morning.

A passenger on the plane tells CBS News that about two hours into the flight, one of the co-pilots left the cockpit to go to the restroom.

A federal government official tells CBS the captain became incoherent, which caused the co-pilot to become concerned. According to the official, the co-pilot convinced the captain to leave the cockpit and then locked him out.

While he was gone, another JetBlue pilot who was traveling on the plane entered the cockpit and took over the other man’s duties.

The captain exhibited odd behavior, randomly striking up conversations with passengers on his way back to the cockpit.

When he realized he was locked out, a passenger says the pilot began screaming “let me in” and acting erratically.

One witness says he started running up and down the aisle screaming.

A flight attendant quickly got on the intercom, saying, “restrain him,” according to passengers.

Several passengers then tackled him to the floor, and they kept him pinned until the plane landed in Amarillo.

One passenger said, “He picked the wrong plane. Huge guys just tackled him. The response was Olympics kind of stuff.”

This YouTube video was allegedly taken by a passenger on the flight:

When the plane landed, witnesses say officers removed the tackled pilot. The airplane is still on the ground in Amarillo and the passengers are still on board.

The jet is an Airbus A320, which holds about 150 passengers.

Reporting from the Amarillo airport, CBS reporter Angelina Perez says,“We’ve been told from the eyewitness that they actually made an arrest. From what we see at the scene right now there are a bunch of cop cars.”

On its website, JetBlue says the plane landed in Amarillo due to “a medical situation involving the Captain.” The airline says the pilot was taken to a local hospital.

JetBlue says it sent another airplane and crew to Amarillo to take the stranded passengers to Las Vegas.

The FBI office in Dallas is investigating the incident. But a federal government source tells CBS News it is being treated as a medical incident and not an attempted act of terrorism.

Denny Kelly is a retired airline pilot and now an aviation safety consultant. He says, “this is a major, major deal.”

He believes the co-pilot should be called a hero.

“Yes, he was, absolutely, he was,” he said. “I’d like to know psychologically how he got him out of the cockpit.”

The Federal Aviation Administration requires all pilots older than 40 to renew their first class medical certificate every six months. Pilots who are under 40 must do so every year. They must pass a physical, which includes a psychological assessment and must disclose all medical conditions and medications they take.

Late Tuesday afternoon, CBSDFW received this statement from the FAA:

“This morning, at approximately 9:53 a.m. Central Time, a Jet Blue flight en route to Las Vegas from New York JFK International Airport was diverted to Amarillo Rick Husband International Airport for an onboard medical emergency. Preliminary information indicates that after landing, it was learned that the co-pilot became concerned that the captain exhibited erratic behavior during the flight. The captain had exited the cockpit during the flight, after which the co-pilot locked the door. When the captain attempted to enter the locked cockpit, he was subdued by passengers. After the flight landed safely, local law enforcement secured the pilot without incident, and he was transported by ambulance for medical evaluation. The aircraft was towed to the terminal building and the passengers were safely deplaned from the aircraft. Passengers are currently awaiting continuation of their travel to Las Vegas. The FBI, FAA, TSA and local law enforcement are coordinating on this incident.”

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