A&E's excellent recent telepic on this very same subject might have cast doubts in some viewers' and critics' minds regarding the merit of the bigger-budgeted theatrical effort to follow. But in the hands of the masterful Paul Greengrass, a director with documentary roots who delivered such gems as the critically acclaimed, docu-like Bloody Sunday and the blockbuster Bourne Supremacy, United 93 is a supreme achievement.

While A&E's Flight 93 focused more on the doomed passengers and crew and their loved ones on the ground in its retelling of the same few hours on Sept. 11, 2001, United 93 allots much screen time to involved personnel at the Federal Aviation Administration, air-traffic control and the military, who watched helplessly as the events involving all four hijacked planes unfolded. With the seizure of United 93 by the four Arab terrorists, Greengrass shifts his focus to the plight of the 40 passengers and crew, catching tiny aspects of their lives and snippets of their phone conversations to reveal how they and those on the ground communicated and learned what was happening.

The film, which more or less unfolds in real time, pulls out all stops in going for verisimilitude. A number of the actual 9/11 traffic control, control tower and military and government personnel play themselves, including most prominently Ben Sliney, the national operations manager for the FAA's operations command center in Herndon, Virginia, who began his first day as FAA manager on 9/11.

In writing his script, Greengrass conducted more than 100 interviews with friends and family members of the passengers and the research reflects great sensitivity, care and generosity. With providence bestowing a Noah's Ark-like variety of passengers for this voyage (those on board represented different ages, nationalities, religions, orientations, etc.), Greengrass gives attention to many beyond the already familiar younger and stronger males who no doubt spearheaded the cabin revolt and assault on the cockpit.

The passengers are not easily identified by name, but several can be recognized by offhand dialogue (e.g., the rugby player, the dad with three kids, the reference to Microsoft, the pair going to Yosemite). Greengrass even humanizes the terrorists, conveying their profound determination, dedication, religious beliefs and fears.

DP Barry Ackroyd, employing a sometimes nervous, sometimes fluid and always probing style in his camerawork, gives the film a rich documentary feel that emphasizes immediacy and uncertainty. The film's editing team achieves a pacing that will leave viewers breathless, and John Powell's music does exactly what it is supposed to do-that is, never get in the way of the story, the characters, or the facts, memories, anger and sorrows of 9/11. Greengrass' choice of largely unknowns for the cast reminds that it's talent, not names, that ultimately matters for an immersive, outstanding moviegoing experience.

United 93 is certain to attract the sizeable audiences it deserves. The one caveat is that because it is so chilling, so emotionally draining, the film is not the kind that audiences will easily return to.

-Doris Toumarkine