The scenario: an aircraft from Westover Air Reserve Base has engine problems and goes down. The practice is necessary because in a matter of weeks, an estimated half-million people will crowd into Westover for a two-day air show.

"We want to make sure that when we do have the air show in September, that we are coordinating and have all the bugs worked out, if and when, we have to respond to an emergency like the one we are simulating today," said Captain Justin Manna, Public Affairs Officer at Westover.

The disaster drill held at Smith and Wesson is done every year or two, to give emergency responders a chance to rehearse their response to a mass casualty incident.

"Transporting this large amount of people to the hospital, treating them, cleaning them up, de-contaminating them and also putting the fire out," said Dennis Leger of the Springfield Fire Department.

Medical personnel give the victims initial treatment before they're sent to the hospital.

"We have 15 seconds to triage our patients. 15 seconds per individual to decide if it is life threatening or something that can be delayed for a few minutes. If it is, we can move on to something more critical," said James Welcome of American Medical Response.