John Wayne Airport conducts a full-scale mass-casualty drill involving OCTA buses, simulating a Boeing 737, and a small Cessna on Friday. (SCOTT SMELTZER, Daily Pilot / April 11, 2014)

John Wayne Airport practiced its response to a major emergency Friday.

Half a dozen county agencies plus hospitals, Delta Air Lines, the American Red Cross and other emergency personnel took part in the drill from 9 a.m. to noon that simulated a crash with multiple casualties.

The Federal Aviation Administration requires the full-scale drill every three years, according to a news release from the airport.

"The purpose of the drill is to test and practice the operational capability of the airport's emergency management system in a real-time environment," the release said.

Friday's simulation used an Orange County Transportation Authority bus as a stand-in for a Boeing 737 that had collided with a small Cessna on the runway.

Officials staged the drill in a secure aircraft parking area on the east side of the JWA airfield.

The rest of the airport continued to operate normally.

-- Jeremiah Dobruck