On June 26, 1982, a Beech D18S (registration N3962) operated by David L. Horsley was involved in an aviation accident near Belen, NM. Investigators recorded the probable cause as: The left engine's oil leak, which led to smoke in the cockpit and compromised the propeller feathering and landing gear extension systems, resulting in a gear-up landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot shut down an engine after oil leaked into the cockpit, filling it with smoke. Unable to extend the landing gear due to hydraulic failure, he executed a gear-up landing at a nearby airport.
What happened
The pilot reported that during the flight, the left engine began leaking oil, which subsequently filled the cockpit with smoke. In response to the situation, the pilot shut down the left engine. However, the propeller failed to completely feather due to the loss of oil pressure. While approaching to land at a nearby airport, the pilot attempted to extend the landing gear but was unable to do so. The aircraft sustained damage during a gear-up landing.
The investigation
The investigation focused on the mechanical failure of the left engine and its associated systems. Key findings included:
Left engine oil leak: The source of the smoke in the cockpit was identified as oil leaking from the left engine.
Propeller feathering failure: The propeller did not fully feather due to the loss of oil pressure, which is typically required for this function.
Landing gear extension failure: The pilot was unable to extend the landing gear during the approach.
Findings
The primary factors contributing to the incident were:
Oil leak: The left engine leaked oil, leading to smoke in the cockpit.
Hydraulic system compromise: The loss of oil pressure affected both the propeller feathering mechanism and the landing gear extension system.
Gear-up landing: The inability to extend the landing gear resulted in a gear-up landing, causing damage to the aircraft.
Probable cause
The left engine's oil leak, which led to smoke in the cockpit and compromised the propeller feathering and landing gear extension systems, resulting in a gear-up landing.