Dense fog had rolled into the area around the time the plane was approaching the airport. Visibility was at half a mile at 3:55 a.m. and had dropped to a quarter of a mile just after 4 a.m. in the area around Marine Corps Air Station Miramar, which is just a few miles north of the crash site, according to the National Weather Service.

Federal investigators are combing a San Diego neighborhood a day after a private jet carrying a music executive and five others crashed there and are presumed dead.