911 Calls From Asiana Flight Crash Released

Some passengers thought emergency vehicles took too long to arrive

(CNN) -- Shortly after Asiana Airlines Flight 214 crashed in San Francisco, passengers and witnesses pleaded with 911 responders to send help -- some frantically, some insistently.

"I'm reporting an airplane crash at SFO (San Francisco International Airport)," an early witness said in calls released by the California Highway Patrol.

"An airplane crash at SFO?" a dispatcher asked.

"Yeah. We were hiking on a trail outside Pacifica and we heard a giant explosion and … an airplane had crashed right there at SFO."