Plane controllers recall 11 September

International flights were diverted to airports outside US

US air traffic controllers who were working on 11 September have recalled their ordeal as hijackers flew planes into the World Trade Center and the Pentagon.

Speaking at a briefing about the moments leading up to the attacks, they also described their frantic efforts to ground thousands of aircraft as the crisis unfolded.

At first they thought it was a conventional hijacking, but within minutes, they were dealing with a crisis unlike anything they had ever seen.

By the end of the day, four hijacked planes had crashed and about 3,000 people had been killed.

About 3,000 people died in the 11 September attacks

The Federal Aviation Administration's Frank Hatfield said it was a crisis unlike anything they had dealt with before.

"On that morning the first US forces to engage the enemy were our air traffic control workforce," he said.

"Before the first military aircraft was launched, before the first police vehicle was despatched, our controllers were already at war."

At 0848 EDT (1248 GMT) on 11 September, American Airlines Flight 11 from Boston bound for Los Angeles slammed into the World Trade Center's north tower in New York.

Cockpit conversation

It has already been reported that when the hijackers took over the aircraft, one of the crew managed to hit a control that allowed air traffic controllers to hear the cockpit conversation.

"Don't do anything foolish," a hijacker was heard to say.

"You are not going to get hurt. We have more planes. We have other planes."

For those 11 minutes we knew what was going to happen and that was difficult

Air traffic manager Michael McCormack

A short time later United Airlines Flight 175 crashed into the south tower.

Hijackers later crashed American Airlines Flight 77 into the Pentagon while United Airlines Flight 93 from Newark crashed in rural Pennsylvania.

Investigators believe passengers may have tackled the hijackers and stopped them from reaching their intended target.

When the first plane crashed into the World Trade Center, New York's air traffic manager, Michael McCormack, immediately suspected a terror attack.

He described his experience as the second plane approached Manhattan.

"Probably one of the most difficult moments of my life was the 11 minutes from the point I watched that aircraft when we first lost communication to the moment that aircraft hit the World Trade Center," he said.

Personal loss

All the FAA air traffic controllers watched helplessly as the jets disappeared off their screens.

But in an unprecedented move they also succeeded in emptying the skies of 4,500 aircraft as they feared more planes could be hijacked.

International flights in mid-air were told they could no longer land anywhere in the US, and many were diverted to Canadian airports.

One manager spoke of his pride at the way his workers handled the intense pressure.

One employee, he said, lost four relatives in the attacks, yet remained at his post until the skies were safe.