A 25-year-old flight instructor safely landed a small plane on Interstate 8 in El Cajon late Friday morning, KTLA sister station KSWB in San Diego reported.
No one was injured in the emergency landing, which one California Highway Patrol official called "nothing short of a miracle."
A student-pilot had been preparing to land at nearby Gillespie Field when the engine failed, according to CHP.
The instructor took control of the aircraft and managed to land the plane safely, avoiding homes, power lines and traffic as he touched down on the busy highway, originally blocking two lanes of freeway before guiding the plane to the Mollison Avenue off-ramp for I-8 West, which was still blocked as of 4 p.m.
The site of the landing was less than two miles from Gillespie Field. Officials said that mechanics may have to be called to remove the plane's wings, because the aircraft was too wide to tow to the airfield.
The plane's tail number, N8125Y, matched a 1979 Piper PA-28. The fixed-wing, single-engine plane with four seats and one engine is registered to a corporation called So Cal Leasing LLC, based in El Cajon.
The Federal Aviation Administration and National Transportation Safety Board were investigating what led up to the engine failure.