First Officer Jason Dowd was able to quietly signal to flight attendants on Tuesday that Captain Clayton Osbon, who abruptly left the cockpit and witnesses said in court documents had been screaming incoherently about religion and terrorists, might need to be restrained in the cabin.

Passengers said the call soon after came over the public address system "restrain him, restrain him." By that time, flight attendants had selected six men to bring down Osbon, who was tackled in the galley and held until landing.

In the cockpit, things were fast-moving. Dowd was joined by an off-duty pilot with the jetliner at roughly 30,000 feet and cruising at 500 miles per hour (805 kph) on the original flight path from New York to Las Vegas.

Just north of Texas, the Kansas City air traffic center handed the A320 over to Amarillo airport tower controllers to handle the emergency landing, according to people familiar with the matter and air traffic control tapes released by LiveATC.net.

"Control tower: (Jet) Blue 191 declare emergency," crackled the radio at the Amarillo control tower. "Uh, we're going to need priority to get into Amarillo and, uh, we're going to need a few minutes to get everything straightened out."

The responses from the cockpit were clipped as controllers read out coordinates. The crew asked for security and medical help to meet them on the tarmac. JetBlue was cleared to land eight miles from the runway and within a few moments was down safely. The diversion took 20 minutes.

FBI TAKES COCKPIT RECORDER

JetBlue was not confirming the copilot's identify or talking about details of the incident, which remains under investigation. But the airline said it had turned over the plane's cockpit voice recorder CVR.L to the FBI.

The "black box" should allow investigators to compare at least some of the flight deck conversations and other sounds with statements from witnesses about the harrowing flight.

The crew, a JetBlue spokeswoman said, had completed their initial interviews with investigators and were given "down time" by the company. Efforts to reach Dowd, whose actions were hailed publicly as heroic, were not successful.

Osbon remained in custody in Amarillo charged with interfering with a flight crew and awaiting a court appearance. JetBlue executives were in contact with Osbon and his family, the airline said.

JetBlue has returned the Airbus plane to service on a different route.

JetBlue reminded all of its 14,000 employees, including 2,200 pilots, of counseling services and other assistance. The company offered legal help to the crew, including Osbon.

The airline also said it would review the incident to see whether the company should change policies on recruitment, training and health screening.

"We believe that our recruitment practices and screening policies are thoughtful, and we believe they work well," said JetBlue spokeswoman Jenny Dervin.

"We're going to take a look at everything in relation to the incident itself. Everything is always up for review," Dervin said, noting the carrier follows Federal Aviation Administration guidelines for pilot fitness evaluations.

Like other airlines, JetBlue offers its flight crew a "safety time out" option that allows them to miss work when they are too tired. Dervin said employees face no penalty for calling a time out, but they will be asked the reason.

Dervin said she didn't know how frequently the time outs are used. She said the airline deals with each one on a case-by-case basis and uses them to spot trends in flight crew fatigue.

The Federal Aviation Administration had no comment on the flight controller details, saying the matter was still under investigation.

AIRLINE STRAIN, LIABILITY

The frightening midair meltdown underscored the intense emotional strain among flight crews and passengers, who face long lines, full planes and economic pressures, industry experts said on Thursday.

But they say the JetBlue disruption was an isolated incident that speaks to a broader trend of stress among airline employees and travelers.

"There's nothing about JetBlue, but it suggests to me that the entire transportation system is just wound a little too tight," said consultant Robert Mann, a former airline executive.

He noted in particular lower pay for airline employees, fuller planes and increased financial pressure to keep flights on time. Passengers, meanwhile, are subject to intense security screening and long lines.

Legal experts say it is unclear if JetBlue faces liability over Tuesday's incident.

"The law is if you are employed by a company and you do something that hurts anybody else, then the company is liable." said Juan Serrano, an aviation lawyer with Griffin & Serrano.

If JetBlue had spotted a warning sign of mental strain in the pilot but failed to act, it might be the target of successful lawsuits, he said.

Passengers could file a claim for emotional distress against JetBlue if they can claim some wrongdoing by the airline, like ignoring signs the pilot had mental issues, said Mike Danko of The Danko Law Firm. Danko specializes in aviation lawsuits.

"If they had no knowledge and had done an adequate check into his history, then the company probably would not have any liability," he said.

(Reporting By John Crawley; editing by Todd Eastham)

• A Permanent Economic Emergency