On April 22, 1984, a Piper J3C-65 (registration N37967) was involved in an aviation accident near Pahokee, FL. Investigators recorded the probable cause as: Engine failure due to fuel starvation caused by an improperly vented fuel tank cap. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A Piper aircraft lost power while cruising at 1,000 feet above mean sea level. The pilot was forced to ditch the plane into Lake Okeechobee. Post-recovery inspection revealed fuel in the tank, suggesting a venting issue caused the engine to starve.
What happened
The aircraft was operating in cruise flight at an altitude of 1,000 feet above mean sea level when the engine suddenly lost power. Unable to maintain altitude or reach a suitable landing area, the pilot executed a water landing, ditching the aircraft into Lake Okeechobee.
The investigation
Following the recovery of the aircraft from the lake, an inspection was conducted to determine the cause of the in-flight engine failure. The pilot reported that fuel was present in the fuel tank after the incident. He noted that the vent on the fuel tank cap appeared not to be properly vented.
Findings
The investigation concluded that the engine had starved for fuel. The presence of fuel in the tank combined with the pilot's observation regarding the fuel tank cap vent suggests that improper venting prevented fuel flow to the engine, leading to the loss of power and subsequent ditching.
Probable cause
Engine failure due to fuel starvation caused by an improperly vented fuel tank cap.