"Attention, all aircraft," a voice said over a loudspeaker in a remote corner of Dulles International Airport. "There has been a crash one and a half miles from Runway 1230. Fuel and souls on board unknown."

As flames and black smoke rose into the air and ambulances and firetrucks raced to the scene, the announcement continued: "This is a simulated Alert 3."

On Saturday, more than 600 people from 50 agencies and organizations -- including 200 volunteers who portrayed crash victims or helped with support services -- participated in an emergency exercise required by the Federal Aviation Administration. The scenario was a simulated airplane crash on airport grounds shortly after takeoff with the possibility that the plane had been brought down by terrorists.

"Every three years, 139 airports are required to test their emergency plans," said Matthew Crosman, the airport's operations duty manager. "It's amazing that something looks good on paper, then you find little problems in the execution."

Crosman and co-organizer Janene Doll began planning the exercise in October, holding monthly meetings with local, state and federal emergency response agencies.

The computer-controlled fire was set at the Dulles Fire Training Facility in a remote section of the airport grounds and did not disrupt normal operations. The facility has a control tower, water supply, triage area and a full-scale steel replica of an airplane fuselage. It is the only one of its kind on the East Coast.

Firetrucks arrived within minutes, shooting jets of water at the fire. Although organizers chose not to use sirens to minimize the concerns of airline passengers and nearby residents, the noise was deafening.

As the smoke changed from black to white and firefighters deemed it safe, 130 "victims" placed themselves on the gravel near the crash, moaning and screaming for help. Five makeup artists had applied "moulage" -- artificial blood, putty, plastic "wounds" and makeup -- to simulate burn and crash injuries.

Doll said the volunteers included airport staff, members of local aid organizations, students, and friends and relatives of the participating fire and police departments. She said the airport would issue certificates to students fulfilling community service requirements and to Scouts earning merit badges.

Natalie Chapman, 16, a student at Loudoun Valley High School in Purcellville, volunteered because a friend's father is an airport employee. Chapman read from an ID badge around her neck: "It says I have burns on 20 percent of my body, my arm is fractured and I have head injuries."

Ten hospitals participated in the drill, conducting their own emergency exercises as the injured arrived. They included Loudoun, Prince William, Reston and several Inova hospitals and emergency care centers. MedSTAR Transport System and Inova AirCare provided helicopters. The Virginia medical examiner's office was on the scene because organizers decided there would be 20 "deaths."

As the fire equipment pulled back, the first ambulances from the Sterling Volunteer Rescue Squad and the Arcola Pleasant Valley Fire Department arrived. The acrid odor of propane filled the air. Emergency rescue personnel pulled on purple disposable gloves and began tending to the victims.

Other rescue staff set up a triage area on the grassy perimeter of the crash site. Three stations -- coded red, yellow and green, to denote the severity of injuries -- were laid out using large tarpaulins and traffic cones. Personnel in charge of each station wore matching colored vests with identifying information written in large letters.

John Bispo, a Washington area firefighter, wore a green vest with "Minor Manager" printed on it.

"Any flight attendants here or anyone with military experience? Where are the Boy Scouts?" Bispo asked as victims with the least serious injuries began arriving.

Workers were evaluated by colleagues from other airports and surrounding jurisdictions who carried clipboards and took notes. "What we're looking for is focusing on the interaction between outside agencies and fire and police," said Mark Rohr, Fairfax County's fire and rescue battalion chief. "All first-responder agencies in this region are very good at what we do, but we don't get tested like this very often."

"Anytime you can create this much realism, it gives [these organizations] a chance to affiliate in more than a tabletop exercise," said Suzanne G. Devlin, Fairfax County's acting police chief. "You feel the weight of the bodies carried on stretchers, hear the crying, the screaming."

Under the supervision of Loudoun County coordinator Tom Dawson, nearly 100 members of the Amateur Radio Disaster Services were stationed at the airport and at area hospitals. Using their own radios and equipment, they helped to track the location of victims and passed on critical information to rescue staff.

"We add a couple of extra links to the communications system," said Evan Alford, a member of the group. "At times like this, normal channels get tied up, and cell phone channels get overloaded."

With the fire and rescue effort completed, officials with the FBI, the National Transportation Safety Board, the medical examiner's office and Loudoun and Fairfax county police began a grid search of the crash area.

"Now that it's a crime scene, we're looking at the manifest and identifying everyone who would have touched this plane," said Michael A. Mason, assistant director of the FBI's Washington field office. The FBI became the lead agency in the investigation because terrorism was the suspected cause of the crash.

Asked whether he felt he was practicing for another disaster on the scale of Sept. 11, 2001, Mason replied: "I feel like the hunter, not the hunted. We're out here to prepare.

"On the terrorism front, if they expect us to roll over like roadkill, it's not going to happen."

Jets of water hit the burning plane during Saturday's emergency simulation at Dulles International Airport. Firefighter Walter Volrie guides crash "victim" Diane Tai to medical personnel. More than 600 people participated in the drill."Victim" Katie Payne, 14, is assisted by Fairfax firefighters.