The North American Aerospace Defense Command, which protects U.S. and Canadian airspace, has said for years that it was alerted too late to the diversion of American Airlines Flight 77 - en route from Dulles International Airport in Northern Virginia to Los Angeles - to prevent the Pentagon attack.
But it was never clear precisely when the Federal Aviation Administration alerted NORAD to Flight 77's diversion. NORAD had pinned the time at 9:24 a.m. and said Langley jets were airborne at 9:30. The FAA had never confirmed that account.
Now, the military is revising its official timeline based on what it described as new information. The old timeline was recently pulled from NORAD's Web site.
"In the past few months, we found there was other information that altered the timeline," said Maj. Douglas Martin, a spokesman for NORAD, which is based in Colorado.
Tomorrow, the independent commission investigating the events of Sept. 11 has scheduled its final public hearing in Washington to examine how the military and the FAA responded to the first attack on the U.S. homeland since the Japanese bombed Pearl Harbor on Dec. 7, 1941.
The hearing is expected to shed new light on whether fighter jets could have been scrambled more quickly. Gen. Ralph Eberhart, the commander of NORAD, is scheduled to testify and release a revised timeline of Sept. 11 events.
Officials from NORAD and the FAA declined to discuss details of the timeline or any information that might have forced a revision. Both agencies said they did not want to pre-empt tomorrow's hearing.
But privately, a federal official cautioned that a precise timeline may never be obtainable. The FAA and NORAD communicated much of their initial information through unrecorded phone conversations.
"A lot of it was unrecorded," the official said. "This is based on people's memories."
But family members of the victims continue to question whether more could have been done to respond sooner and possibly avert at least one of the attacks.
"There was a delayed response from NORAD," said Mary Fetchet, whose son was killed in one of the World Trade Center towers in New York.
About 90 minutes elapsed from the time of the first plane hijacking to the time the Pentagon was hit, said Fetchet, chairwoman of Voices of Sept. 11, a group of relatives of victims. "That's a long time to have planes hijacked within our own airspace without being intercepted," she said.
But Martin, the NORAD spokesman, said his agency, which focuses on foreign fighter attacks, could scarcely have contemplated attacking U.S. commercial airliners.
"A lot of people are judging Sept. 11th with Sept. 12th eyes," he said. "On Sept. 11, our eyes and ears were focused on threats coming toward Canada and the United States."
Even if NORAD had been alerted sooner, it is still not clear that the Pentagon strike could have been averted. Military rules of engagement at the time did not allow pilots to shoot down a hijacked airliner without a presidential order. President Bush did not issue such an order until after the Pentagon was hit.
Bush was briefed yesterday by Kenneth Feinberg, the special master appointed after 9/11 to oversee the fund paying compensation to victims.
Feinberg said the fund will distribute about $6.9 billion to more than 5,500 people. Under the law creating the fund, administrators had until midnight last night to decide how much each applicant would receive.
The Daily Press of Newport News, Va., is a Tribune Publishing newspaper. The Associated Press contributed to this article.
