"This landmark flight has historic implications since it's the first time a Global Hawk has not only flown from Beale, but anywhere in the United States on an official Air Combat Command mission," base spokesman Capt. Michael Andrews said in a statement.

Beale-based pilots are flying the drones daily on combat missions in the Middle East, Andrews said. The planes are operated by four-person crews from virtual cockpits the size of shipping containers.

The planes are designed to fly at high altitudes for 40 hour-missions covering as much as 10,000 miles, mostly providing aerial surveillance. The aircraft, which can cost more than $80 million each, can reach an altitude of 65,000 feet and send back high-resolution imagery.

The Hawks are among a growing fleet of unmanned aircraft that also includes the missile-carrying Predators and five-pound Ravens that are small enough to be carried in soldiers' backpacks.

Beale is to have seven Global Hawks by 2009. It is currently the only U.S. base with the drones. Eventually the Air Force's fleet will include 54 of the Global Hawks, but most will be based overseas.

Outside medical experts who reviewed the plan suggested focusing on monitoring epidemiological patterns of disease in those exposed.

In a Sept. 15 draft, the institute proposed examining specific sections of the lungs and creating a "tissue bank" to preserve certain organs and bodily fluids for later testing.

The institute said reviewers had raised several questions, including concerns that "the draft document could be misinterpreted or misapplied, hindering rather than furthering progress in addressing WTC health concerns."

"This study has many insurmountable barriers to overcome," wrote Dr. David J. Prezant, chief medical officer for the city Fire Department. Prezant, whose review was posted on the Web site, said one of those barriers was the "politics of causality," a reference to pending lawsuits filed against the city by injured workers.

Because autopsy results are often used in civil lawsuits, the results collected by the institute - while intended as a scientific study - could be used as a trial tool for lawyers and others with an "undeniable self-interest" in the cause of death, Prezant said.

The collapse of the twin towers sent thick plumes of concrete dust, fiberglass, asbestos and lead into the air in lower Manhattan. The tainted air was taken in by thousands of ground zero workers in the weeks after the terrorist attack that killed 2,749 people.

The guidelines were intended to be used nationwide in cases such as the death of New York City police detective James Zadroga, who died last January. Zadroga spent 470 hours working amid the toxic fumes, and fell ill within weeks.

An autopsy found the 34-year-old detective died as a result of ground zero exposure, finding that there was material "consistent with dust" found in his lungs.

Awadallah would have been convicted last spring had a lone juror not held out for acquittal, forcing a mistrial.

The 21-year-old college student showed up on investigators' radar just days after the 9/11 attacks. His first name and a phone number were found on a scrap of paper in a car parked at Dulles Airport near Washington, a car that had been driven there by Nawaf al Hazmi, one of the 19 hijackers.

The phone number was traced to Awadallah's residence in San Diego, a city in which al Hazmi and fellow hijacker Khalid al Mihdhar lived for several months beginning in early 2000.

Pair helped hijack jet

Al Hazmi and al Mihdhar helped hijack American Airlines 77, which crashed into the Pentagon.

Awadallah, a Venezuela-born Jordanian citizen, has lived in the U.S. since 1999. His father is a U.S. citizen.

He told investigators he worked at the same gas station and prayed at the same mosque as Hazmi, but repeatedly denied knowing al Mihdhar, even when shown photos of him.

Awadallah was detained as a material witness on Sept. 21.

At a grand jury hearing that October, he was confronted with a school examination booklet in which he appeared to have written about meeting men named Nawaf and Khalid. Awadallah initially claimed it was not his handwriting, but later changed his testimony.

While prosecutors concluded Awadallah was just an acquaintance with no knowledge of the attack, they said the contradictory statements about al Mihdhar had hampered the grand jury investigation, leading to charges of perjury.

His attorneys argued that their client, exhausted, confused and frightened after being detained for weeks in solitary confinement, simply had a memory lapse.

Perjury indictment tossed

In early 2002, a federal judge threw out a perjury indictment against him, citing errors made when investigators applied for an arrest warrant.

The judge also ruled that Awadallah had been the victim of coercion by investigators and threw out evidence seized after he was taken into custody, including videotapes and a picture of Osama bin Laden.

The case was later reinstated by an appeals court.

Some of the jurors said Friday after the verdict they were appalled at the way Awadallah had been treated by the government, and believed the statements he made during his grand jury session were prompted by fear and confusion.

"The treatment he received as a witness, a material witness, was really unconscionable, and it had to affect his testimony," said juror Nancy Sosnow, 64, of the Bronx.

Federal prosecutors declined to comment.

Intense scrutiny

The movements of al Hazmi and al Mihdhar in the two years leading up 9/11 have been the subject of intense scrutiny and examination of the lack of information sharing within the U.S. intelligence community.

The two Saudis rented a room in the San Diego home of a longtime FBI informant, and also befriended Omar al-Bayoumi, a Saudi who had drawn FBI scrutiny in the past.

The FBI were not made aware by the CIA that al Hazmi and al Mihdhar were in the U.S. until mid-2001, but a report later found the investigation of al Mihdhar had been ''given to a single, inexperienced agent.''

Awadallah said after the verdict Friday that he had no plans to leave San Diego and the U.S.

"There's no better place to be," he said, smiling.