Pham, 20, and her boyfriend were walking in a parking lot Sunday when they saw a twin-engine Cessna crash, she told the Los Angeles Times.
"We looked up to see the plane falling nose first," she told the Times. "It was so heartbreaking just seeing the plane crumbled into pieces."
Five people on board the small airplane were killed but nobody on the ground was hurt when the plane crashed in the Southern California parking lot, authorities said.
The pilot of the Cessna 414 declared an emergency before crashing about a mile (1.6 kilometers) from John Wayne Airport, Federal Aviation Administration spokeswoman Arlene Salac said.
The plane was heading to the airport southeast of Los Angeles when it came down and struck an unoccupied parked car in the lot of a Staples store and a CVS pharmacy, Orange County Fire Authority Captain Steve Concialdi said. There was no fire and nobody on the ground was hurt, he said.
Photos from the scene showed the plane upright but on its belly and the car damaged. Several roads surrounding the shopping center and the South Coast Plaza mall across the street were closed.
The plane is registered to the San Francisco-based real estate company Category III, according to an FAA database. A phone call to the company was not immediately returned Sunday.
The FAA and the National Transportation Safety Board will investigate the cause of the crash, Salac said.