Background
On October 4, 2019, at 1713 eastern daylight time, a Piper PA46-310P, registration N4385K, was substantially damaged during an accident near Harrisburg, Pennsylvania. The private pilot and a passenger sustained minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Accident Sequence
According to a written statement, the pilot conducted a thorough preflight inspection and had the airplane serviced with 30 gallons of 100LL aviation gasoline. He estimated that the 122-gallon fuel system contained 77 gallons at departure. The flight was described as "unremarkable." Upon arrival at the destination airport, he was cleared for a visual approach and reported referencing localizer and glideslope indications during descent.
The pilot stated that after lowering the landing gear and extending flaps, the engine "cut out." He switched fuel tanks and attempted to restart the engine unsuccessfully, then retracted the landing gear and performed a forced landing to the Susquehanna River.
Wreckage Recovery and Examination
The airplane remained submerged in the Susquehanna River until October 16, 2019, when it was recovered. Post-recovery examination revealed the airplane was intact but the fuselage was deformed aft of the cabin door. Both wings were cut at their roots by recovery personnel. Before wing removal, each wing was drained: the left wing contained 12.5 gallons of fuel and 10 gallons of water; the right wing contained 17 gallons of fuel and 15 gallons of water.
Flight control continuity was confirmed from controls to all surfaces. Fuel system continuity was confirmed from wing roots to the fuel metering unit. Electrical power was applied to both fuel boost pumps, and they operated when energized.
Engine Examination
The engine spark plugs displayed normal wear and evidence of water exposure. The engine was rotated by hand; both magneto impulse couplings snapped and spark was produced at the ignition leads of the top six spark plugs. The engine was removed for examination at the manufacturer's facility. Prior to test cell placement, some components required repair or replacement due to water submersion, damage, or contamination. The starter motor was replaced after propeller rotation revealed binding. Ignition timing was confirmed on both magnetos before drying, then reinstalled and timed to as-found values.
In the test cell, an initial engine start attempt failed. Investigation revealed the fuel manifold was contaminated and blocked due to water submersion. The manifold was removed, disassembled, cleaned, reassembled, and reinstalled. A subsequent start attempt succeeded; the engine started immediately, accelerated smoothly, and ran continuously at all power settings without interruption. The examination and test run revealed no pre-impact anomalies that would have prevented the engine from producing rated horsepower.
Flight Track Analysis
Examination of the airplane's flight track and engine data monitor data showed an increase in lateral g-forces as it aligned with the final approach localizer course. The airplane continued its approach left of the localizer in a right-wing down or slip configuration, consistent with compensation for gusting wind from the right side.
Pilot's Operating Handbook Note
The pilot's operating handbook for the airplane states: "Prolonged slips or skids which result in excess of 2000 feet of altitude loss or other radical or extreme maneuvers which could cause uncovering of the fuel outlet must be avoided as fuel flow interruption may occur when the tank being used is not full."