ALEXANDRIA, VA. – Reading from radiophone transmissions, a federal prosecutor transfixed the courtroom at Zacarias Moussaoui’s sentencing trial yesterday with a minute-by-minute account of Al Qaeda’s hijacking of American Airlines’ Flight 11 and the plane’s journey into the north tower of the World Trade Center on September 11, 2001.

“We are flying low. We are flying very very low. We are flying way too low,” flight attendant Amy Sweeney told ground controllers who had asked at 8:44 a.m. where the plane was. Then a few seconds’ pause, and finally: “Oh my God, we are way too low!” The phone went dead at 8:46 a.m. as the Boeing 767 jetliner hit the tower in the first of four crashes by hijacked jetliners that day.

Moussaoui, the confessed Al Qaeda conspirator who is facing a life-or-death decision, was as electrified as the jury and the audience.

Leaving the courtroom for a recess moments later, the 37-year-old Frenchman of Moroccan descent surged from his chair, pumped his right fist in the air and shouted: “Allah Akbar! God curse America! Bless Osama bin Laden!” He usually mutters these invocations when leaving court.

The actual audio recordings of radiophone calls by flight attendants on Flight 11 have been played in public before. But to avoid inflaming the jury at this sentencing trial, prosecutors and defense attorneys agreed instead to read an account of the flight, including major sections of the phone call transcripts.

Nevertheless, the reading by Assistant U.S. Attorney David Raskin riveted the jury and audience – all the more so because it came after two hours of mind-numbing testimony by FBI agent James Fitzgerald about how the bureau tracked the hijackers after September 11.

Around the courtroom, heads had been left nodding by Mr. Fitzgerald’s detailed and precise description of innumerable hotel receipts, phone call records and financial transactions between 19 men with unfamiliar Arab names, which the FBI gathered to reconstruct how they circled the globe and arrived in America.

That changed when Mr. Raskin took over and opened with the first transmission from flight attendant Betty Ong aboard Flight 11 to American Airlines ground workers at 8:19 a.m.: “The cockpit is not answering. Somebody’s been stabbed in business class. I think we’ve been Maced. We can’t breathe.”

The point of Mr. Fitzgerald’s long description of the pre-attack behavior of the September 11 hijackers was to show how similarly they acted: 13 got new passports to remove telltale indications they had visited Pakistan, 10 used e-mail accounts and public computers, 15 signed up at fitness gyms, five bought short-bladed knives, four trained on jet simulators and five bought flight training computer discs. Nearly all communicated with an Al Qaeda cell in Hamburg, Germany, and got funds wired to them in this country from one of three Al Qaeda operatives.

At some point, prosecutors will bring on witnesses to show that Moussaoui also did many of those things and got money from the same source, but Mr. Fitzgerald never mentioned Moussaoui in his testimony. Nor did he say there was any contact whatsoever between Moussaoui and the 19 hijackers, a point the defense has already stressed.

Earlier, defense attorney Edward MacMahon got FBI agent Michael Anticev to acknowledge on cross-examination that the FBI was aware years be fore September 11 that Al Qaeda had plans to fly airplanes into prominent buildings.

Moussaoui’s lawyers are portraying him as a pathetic loner who dreamed of becoming a terrorist but was shut out of September 11 planning and considered by one Al Qaeda leader “cuckoo in the head.”

The defense also wants to show the government knew far more about brewing Al Qaeda plots than Moussaoui did, and in that vein pressed Mr. Anticev on what the FBI was doing to follow up on warning signals before September 11.

Mr. Anticev at first asserted, “I don’t think anybody was looking at using aircraft as weapons,” but acknowledged under questioning that the FBI had been aware before September 11 that an Algerian group linked to Al Qaeda planned to fly airliners into the Eiffel Tower and into a cathedral in Strasbourg, France.

He said he also knew that an Al Qaeda operative arrested in the Philippines in 1995 had told investigators of plans to fly a plane into CIA headquarters, but Mr. Anticev said he personally did not hear that until after September 11.

Clad in a red scarf and sweater, Moussaoui’s mother, Aicha, sat three rows behind her son in the courtroom most of the day; he glanced at her when she entered but ignored her thereafter. She said later he was angry with her for speaking to his court-appointed lawyers, whom he has disavowed.

Moussaoui pleaded guilty in April to conspiring with Al Qaeda to hijack planes and commit other crimes. The jury will choose between execution or life in prison without possibility of release.

To obtain the death penalty, prosecutors must first prove Moussaoui took an action that led directly to deaths on September 11. Moussaoui denies he had any role in September 11 and says he was training for a possible future attack on the White House.