SAN DIEGO - The six people onboard a small plane that crash-landed on a California neighborhood amid dense fog were all killed, according to investigating authorities.

The Cessna 550 Citation, which federal records show belonged to music agent Dave Shapiro, plummeted into a residential area of San Diego at 3.47am local time on May 22, according to the National Transportation Safety Board (NTSB).

It was not immediately clear what caused the Cessna to come plunging into the Murphy Canyon neighborhood, about 3.2km from the Montgomery-Gibbs Executive Airport where the aircraft was headed.

In an audio recording posted to air traffic website liveatc.net, the pilot can be heard asking about weather conditions prior to descent, while indicating that visibility was down to a minimum.

“Doesn’t sound great, but we’ll give it a go,” the pilot said.

As the plane came down, it clipped a power line and the impact of the crash set several nearby houses and vehicles alight, jolting families awake before dawn.

“The pilot and passengers were fatally injured,” NTSB investigator Dan Baker told a press conference on May 23. He added that no one on the ground had been seriously hurt.

While Mr Baker did not specify the number of fatalities, the US Federal Aviation Administration previously said the private plane had six people onboard.

The San Diego County medical examiner&rs...