 On 10 February 1933 during a night flight from San Francisco to Los Angeles, California a routine flight took a turn for the worse.Just after passing over Delano at an altitude of about 2000 feet, co-pilot Berkenkamp was in the cabin speaking with a passenger when one of them saw smoke coming from a cabin heater vent.Berkenkamp immediately went forward to notified Pilot Bellande and then returned to the cabin to see what could be done.