On August 14, 1982, a Lake LA-4 (registration N1104L) operated by Robert Bernards was involved in an aviation accident near Lake Tahoe, CA. Investigators recorded the probable cause as: The inability of the bilge pump to stop water from entering the aircraft during taxi, leading to sinking and loss of the airplane. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An amphibious aircraft sank in deep water during pre-flight taxi after the bilge pump failed to stop water flowing into the cabin, forcing the pilot and four child passengers to abandon ship.
What happened
The incident occurred during what was scheduled to be the fourth sight-seeing flight of the day. As the amphibious aircraft was being taxied in preparation for takeoff, the pilot observed water actively flowing into the cabin area. The crew attempted to manage the ingress using the onboard bilge pump, but the system was unable to quell the flow of water. With the situation becoming untenable, the pilot and the four child passengers evacuated the aircraft immediately. Shortly after the evacuation, the plane sank in deep water. The aircraft was not recovered from the site.
Findings
The primary factor leading to the loss of the aircraft was the failure of the bilge pump to control water ingress during the taxi phase. This mechanical limitation resulted in the total loss of the amphibious craft as it sank beyond recovery.
Probable cause
The inability of the bilge pump to stop water from entering the aircraft during taxi, leading to sinking and loss of the airplane.