What happened
While operating approximately 150 miles southwest of Monterey, the pilot of the aircraft experienced mechanical issues with the right engine. The engine began producing unusual noises, running roughly, and displaying high cylinder head temperatures. Although the pilot notified Oakland Center regarding the situation, no formal emergency was declared at that time.
In an attempt to manage the heat, the pilot tried to operate the right engine cowl flap, but the mechanism failed to function. To mitigate the rising temperatures, the pilot increased the fuel flow to the right engine, but eventually found it necessary to decrease power to that engine to maintain operation. This created an asymmetric power condition, requiring increased power from the left engine to maintain flight.
This imbalance led to several critical issues. The increased power demand caused the fuel consumption to exceed the original flight plan. Additionally, the flight attitude necessitated by the asymmetric thrust caused periodic unporting in the outboard fuel tank pickups. After exhausting the fuel from the inboard tanks, the pilot attempted to utilize the outboard tanks but could not maintain steady engine power. Consequently, the pilot was forced to ditch the aircraft approximately 20 miles before reaching the coastline.
Findings
- The right engine suffered from high cylinder head temperatures and irregular running.
- A malfunctioning cowl flap prevented effective engine cooling.
- The necessity of asymmetric power led to unporting of the outboard fuel tanks, causing fuel starvation.