In a distinctly personal selection that reflects the origins ofthe Tribeca Film Festival, organisers have chosen the world premiere of PaulGreengrass' United 93to open next month's annual event.

Greengrass' homage to the passengers and crew of United AirlinesFlight 93 that crashed outside Shanksville, Pennsylvania, on September 11 2001was filmed in real time with an improvised script using little-known or unknownactors.

Family members of those who perished on the flight, 9/11 groupsand first responders will attend the screening of the Working Title-producedpicture which is being distributed by Universal in the US on April 28.

"9/11 changed us in indescribable personal ways, but also byforever altering our downtown community," festival co-founder JaneRosenthal said.

"As we enter our fifth festival, we are honoured to showcasea film that portrays a story of bravery and sacrifice of the men and women whodedicated their lives that day aboard United flight 93. We are humbled to hosttheir families, first responders, and others who were most profoundly affectedthat day."

"The events of 9/11 had a massive effect on me, likeeveryone, and I wanted to use my position as a filmmaker to contributesomething so they are not casually forgotten," Greengrass added.

"United 93 tells one story of that morning and I hope that by showing thefilm at Tribeca, whose roots and inspiration grew in response to thedevastation of 9/11, we will be reminded of the courage of all those on boardand also the thousands of men and women who confronted similarly unimaginablescenarios in New York and Washington."

Greengrass produced United 93 with Lloyd Levin and Working Title's Tim Bevan and EricFellner.

The Tribeca Film festival runs from Apr 25-May 7. For more detailsvisit the official website at