Just minutes after the first plane slammed into the World Trade Center, Officer Timothy Hayes, a pilot for the New York Police Department's aviation unit, was in the first helicopter to reach the tragic scene.
"The smoke had covered 90 percent of the entire roof, so I couldn't even see the roof to make an evaluation of where we could go," he said. "We were looking at probably 15 to 20 stories burning simultaneously. Probably well over 1,000 degrees, you know, if not more."
Hayes' recollection helps answer the question that many Americans have asked: Why couldn't helicopters rescue people from the top of the World Trade Center before the towers crumbled?
'The Worst of All Possible Situations'
Though helicopter rescues have flown hundreds of people to safety in other instances, aerial rescues would not have worked on Sept. 11, according to authorities.
"Well, there's high-rise fires and then there's the 11th," said Lt. Glen Daley, a pilot for the NYPD's aviation unit. Whereas a typical high-rise fire involves tremendous heat and smoke, he said, "add to that scenario hundreds of thousands of pounds of jet fuel as an accelerant to the fire. Multiply the heat factor … now you've got the worst of all possible situations playing themselves out."
Daley, who was at the command center during the World Trade Center attacks, added: "People may have in their mind's eye a view of this pristine roof, salvation … Those roofs were totally compromised and with thick, acrid, black smoke, intense heat coming up from the fire."
Even if helicopters had been able to carry out a rescue mission, officials said, nobody was able to make it to the roof.
Above a Towering Inferno
"One of the first calls I got was the people on the ground calling us to immediately check the roof," said Hayes.
At first he thought he saw a clear corner, "but it was still covered in smoke and there was numerous obstructions," he said. "I said, 'Captain, this is impossible. This is undoable. I can't see the roof.'"
Still, Hayes and his crew circled the towers, — 1,700 feet in the air amid thick, black smoke — hoping to make a daring rescue.
They did not know they were in grave danger, until they saw an airplane in all-too-close proximity.
"I turned to Pat, my pilot, I said 'Jesus Christ, there's a second plane crashing,'" said Hayes. "And then I realized how close it was coming to us. I thought it was going to impact our aircraft. So we climbed. He went underneath us."
Hayes could actually see people inside the buildings, leaving him with the heart-wrenching feeling that people were trapped — and he couldn't reach them.
"I never felt so helpless and guilty in my life," he said. "When you get there with these millions of dollars of equipment … and there was absolutely nothing we could do. There was nothing. We couldn't get on that roof, we couldn't get people out of that building."
Hayes said the rescue options were weighed. "This isn't going to work," it was decided of a possible air rescue. "We're going to cause more harm than good right now."
The roof of the South Tower, said Hayes, was totally obscured. As for the North Tower, "there was nobody on the roof," he said.
Roof Is Not Safest Option
Though some people were rescued from the World Trade Center's roof after the 1993 basement garage bombing, fire evacuation plans for the buildings never included a rooftop escape. There was only one exit to the roof, and the usual procedure to discourage jumpers and to protect vital communications equipment was to keep it locked.
The Port Authority said there is no evidence that anyone was able to get close to the door.
In any case, the roof is usually not the safest option in a high-rise emergency, experts said.
Going to the roof of a burning high-rise building can actually be one of the worst things you can do, according to Vince Dunn, a former deputy chief in the New York City Fire Department.
"We want people to get below the fire," he said. "If you're one floor below the fire, you're safe. The most dangerous place you can be is above a fire in a stairway or in a hallway. Heat, smoke and flames rise."
Also, getting to the roof may not be so easy. "Many stairways do not go to the roof," he said. "You may get trapped in that stairway that dead-ends."