Flight Preparation
Before departure, the pilot briefed passengers on emergency procedures. The outboard fuel tanks were empty, and the inboard tanks were filled. The flight departed and climbed to 8,500 feet mean sea level (msl), proceeding toward the destination airport.
Loss of Engine Power
Approximately 10 miles from the destination, while flying at 1,000 feet msl, the left engine began losing power. The airplane did not yaw. The left cowl flap was closed at the time. The pilot observed the left fuel flow light illuminated, but fuel pressure remained within the green arc, indicating 38 to 42 psi. The pilot switched both fuel selectors to the outboard tanks, which were empty, activated both emergency fuel pumps, and attempted to crossfeed fuel to the left engine. These actions did not restore power. The left engine manifold pressure decreased to 18 inches of mercury (inHg). The right engine was at full power, and the pilot maintained airspeed at or slightly above "blue line" (best single-engine rate-of-climb speed).
Emergency Procedures
Approximately 2 to 3 minutes after first noticing the power loss, with manifold pressure indicating 15 inHg, the pilot slowed the airplane below blue line airspeed in an attempt to gain altitude. Seeing boats nearby, he moved the left propeller control to the feather position, but the propeller did not feather. The left engine rpm remained in the upper green arc throughout the event, and no oil was observed exiting the left engine cowling. The flight could not maintain altitude.
Ditching
The pilot instructed passengers to don but not inflate their life vests. He maneuvered the airplane into the wind near the boats and ditched with the flaps and landing gear retracted. All occupants exited the airplane and were rescued by one of the boats.
Post-Accident
The airplane was not recovered, preventing determination of the cause of the left engine power loss or the failure of the propeller to feather. The airplane's Pilot's Operating Handbook/Airplane Flight Manual states that if the fuel flow light illuminates and fuel is present in the corresponding tank, a malfunction of the flapper valve in the surge tank has occurred. The inboard fuel tanks are equipped with such a system.