The exercise was designed to test the readiness of the airport should the unthinkable happen.
Fake victims lay on the tarmac of the LA/Ontario International Airport during a full-scale disaster drill Wednesday.
"In an emergency plan exercise you plan for various components of emergencies," said Paul Greiner, superintendent of operations at LA/Ontario International Airport.
The drill comes on the heels of Monday's close call at JFK International Airport in New York. In that very real situation, an Air France Airbus clipped the tail of a much smaller Comair commuter jet.
Wednesday's simulation involved a crash between two airplanes, one crossing the runway as another takes off.
"If there is a nexus to terrorism it is going to be one response. If it's an accident, it's going to be another response," said Nico Melendez, spokesman for the Transportation Security Administration (TSA). "So we need to define roles. That's why exercises like these are good because it helps us to define those roles."
Those roles can mean life or death for victims in a real disaster.
Part of the emergency drill includes triaging the victims, determining which ones can be saved and which ones cannot.
The exercise also involved a few unexpected surprises for firefighters first on the scene. In one case, one of the 90 simulated victims is pregnant and about to go into labor.
"It is to see how you are prepared and how you handle the situation," said Greiner.
The un-rehearsed drill is required by the Federal Aviation Administration (FAA) every three years and brings together local, state and federal emergency responders who work jointly during a disaster.