Events
The aircraft had completed an aerial survey and landed at Brown Field for customs clearance. During engine restart, a witness observed two short yellow flame bursts from the left engine exhaust. While taxiing, the witness heard a popping sound, which ceased when power was applied to cross runway 26L. The aircraft stopped briefly before entering the runway; no run-up was observed. Witnesses then heard a series of popping sounds resembling automatic gunfire and saw the aircraft between 600 and 1,000 feet above ground, wings level with landing gear retracted. The aircraft made an abrupt left turn at a 45-degree bank, the nose dipped, then raised, followed by another left turn that resulted in an inverted attitude with about 30 degrees nose low. It then returned upright in a shallow right bank before disappearing behind buildings and terrain.
Maintenance History
A work order from May 20, 1997, noted that the left manifold pressure fluctuated in flight. Maintenance lubricated both wastegates, and a test flight revealed the left engine manifold pressure lagged behind the right. On June 18, 1997, the left engine differential pressure controller was removed and replaced to address a discrepancy where the left manifold pressure fluctuated by 2 inHg and rpm varied by 100 during cruise. The accident pilot conducted a test flight that afternoon and found the discrepancy persisted at cruise power settings, though the engine operated normally at high and low power.
Post-Accident Examination
Functional checks of various components were performed. The left governor showed no discrepancies. The left differential pressure controller was damaged and produced inconsistent test results. The left density controller was too damaged for testing. The right engine density and differential pressure controllers tested satisfactorily. Both left and right fuel pumps operated within specifications. Both fuel servos were damaged. One injection nozzle on the left engine was partially plugged, while all others passed flow testing within specifications.
Probable Cause
The probable cause was determined to be the loss of power in the left engine for undetermined reasons and the pilot's subsequent failure to maintain minimum single-engine control airspeed. A contributing factor was the pilot's decision to fly with known deficiencies in the equipment.