By MARIO FOX
Associated Press Writer

CHICAGO - Passengers aboard an American Airlines jetliner acted quickly to subdue a man described as being mentally ill who tried to enter the cockpit but some questioned airplane security in the wake of the Sept. 11 terrorist attacks.

During the struggle on Monday, the pilot made a distress call and two F16 fighters intercepted Flight 1238 from Los Angeles and escorted it to Chicago, FBI spokesman Ross Rice said.

No one was injured, and the plane landed safely at O'Hare International Airport with a crew of nine and 153 passengers.

Passenger Bill Neff told the Intelligencer Journal of Lancaster, Pa., that the man entered the cockpit of the Boeing 767 before being tackled by fellow passengers.

"I heard a stampede. These men were running after him into the first-class section. Then the guy hit the cockpit door and it sprung right open," Neff said. "I was up there, too, in two seconds."

Edward A. Coburn, 31, of Fresno, Calif., was in custody and was to be charged Tuesday with interfering with a flight crew, a felony, Rice said.

"I was under the assumption that there were sky marshals on the plane," said Neff, who was returning from a vacation to Sydney, Australia, with his wife Barbara. "I had a false sense of security."

"(Coburn) ran just as fast as he could screaming toward the cockpit and opened the door," passenger Brian Karnov told WBBM Radio, adding that pilots and passengers knocked Coburn down then wrapped him in a blanket.

"He kept screaming 'Save the tower! Save the tower!' He was under some kind of delusion that the plane was going to crash into the Sears Tower and he wanted to save it," Karnov said.

Rice said Coburn's father, who was also on the flight, alerted the flight crew shortly before the plane left Los Angeles that his son was acting strangely and suffered from some sort of illness.

"This man had some sort of mental problem. He is on medication and under a doctor's treatment," Rice said. "This is not a terrorist incident and was not related in any way to the attacks on Sept. 11."

Last week, Transportation Secretary Norman Y. Mineta ordered all airlines to strengthen cockpit doors within 90 days. Several already have been doing so since the terrorist attacks.

Cockpit doors on airplanes have been designed to allow flight crews to escape quickly in an emergency.

"One good thing is the men knew exactly what they were going to do when they saw that guy charging," Neff said. "We as individuals need to have our eyes and ears open wherever we are. The rules have changed."