Introduction
A Shrike Commander aircraft operating a visual flight rules (VFR) charter flight from Horn Island to Saibai and Boigu Islands experienced a dual engine failure during the return leg, leading to a ditching. The aircraft was occupied by five people, all of whom escaped and made their way ashore after the aircraft settled on the seabed.
Flight Details
The flight departed Horn Island and flew to Saibai Island, taking 32 minutes, then continued to Boigu Island, arriving after an additional 13 minutes. The aircraft then departed Boigu for the return to Horn Island, with an expected flight time of 35 minutes. The pilot reported maintaining 5,500 ft until commencing descent at 35 nautical miles (NM) from Horn Island. He tracked to join the final approach for runway 14 by 5 NM, reducing power at 1,500 ft. At 5 NM from the runway, the pilot extended the landing gear and approach flaps and began a long final approach.
Engine Issues and Ditching
When the aircraft was approximately 3 NM from the runway, both engines began to surge, initially causing the aircraft to yaw to the right. The pilot initiated engine failure procedures, retracted the flaps, and attempted to identify the failing engine by retarding each throttle. He deduced the right engine was failing, shut it down, and feathered the propeller. Shortly thereafter, at an altitude of approximately 200 ft above the water, the left engine also lost power. The pilot established a glide, advised passengers to prepare for ditching, and transmitted a MAYDAY on the flight service frequency before the aircraft contacted the sea. The aircraft quickly filled with water and settled on the seabed, but all five occupants were able to escape and reach the shore.
Investigation Findings
The investigation identified several findings: the pilot was correctly licensed and qualified for the VFR charter operation; the aircraft was dispatched with an unusable fuel quantity indicator; the right engine fuel control unit was worn, allowing additional fuel flow and increasing consumption by about 6 L/hr; inappropriate fuel consumption rates were used for flight planning; the aircraft fuel log contained inaccuracies that substantially underestimated total fuel used; at the time of the occurrence, there was no usable fuel in the aircraft fuel system; and although the pilot met Civil Aviation Safety Authority criteria for the role of chief pilot, he lacked the expertise to effectively ensure the safety of company flight operations.