Accident Sequence
On March 30, 2024, at about 1448 eastern daylight time, a Piper PA-24-250, registration N7538P, was substantially damaged during a ditching in Narragansett Bay near North Kingstown, Rhode Island. The private pilot and one passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
The pilot reported flying two uneventful flights earlier that day totaling about 1 hour 45 minutes. Before the third flight, she performed a walk-around inspection using the preflight checklist. She started the engine, taxied, and performed the before-takeoff checklist with no engine discrepancies. She departed with the fuel selector on the right tank and proceeded to the destination.
When about 10 miles from the destination airport, she contacted the tower controller and was instructed to expect a straight-in approach to runway 23 and to report on a 2-mile final. At about 5 miles out, she began the prelanding checklist, which included turning on the electric fuel pumps. When approximately 1/2 to 1 mile from the runway and about 800 ft above ground level, she noticed the airplane was low relative to the precision approach path indicator. She increased the throttle, but the engine did not respond.
The pilot verified the mixture was full rich, the fuel selector was on the fullest tank, and checked the magnetos. She did not apply carburetor heat. Engine power was not restored. She declared an emergency, the passenger unlocked and unlatched the entry door, and the pilot ditched the airplane into Narragansett Bay.
Postaccident Examination
Examination of the airplane revealed substantial damage including compression buckling on both sides of the fuselage aft of the engine firewall, the right side of the aft fuselage, and the left side of the fuselage aft and below the aft window. About 30 gallons of 100 low lead fuel and 4 gallons of water were drained from the wing tanks.
The engine examination showed that the throttle, propeller, mixture, and carburetor heat controls remained attached at their attach points. All except the throttle control could be manipulated; the throttle could not move due to postaccident corrosion. Crankshaft, camshaft, and valvetrain continuity was confirmed. Inspection of the ignition, oil lubrication, and electric fuel pumps revealed no evidence of preimpact failure or malfunction.
Fuel System Examination
The engine-driven fuel pump exhibited suction and pressure at the inlet and outlet fittings during hand actuation. Disassembly revealed a foreign material piece about 1 inch long, 0.75 inch wide, and less than 0.05 inch thick in the inlet section. The material and flexible fuel hoses from the engine compartment were sent to the NTSB Materials Laboratory.
The laboratory determined the foreign material was consistent with nitrile rubber and its composition matched the inner layer material of one of the recovered fuel hoses. Bisection of all recovered fuel hoses showed no missing or separated inner layer material.
By design, the airplane’s engine-driven fuel pump delivers fuel to the carburetor, while the electric fuel pumps connect in parallel to provide redundancy and a means to bypass the engine-driven pump if obstructed or failed.
Carburetor Icing Conditions
According to the airplane’s owner’s handbook, the approach and landing checklist specified turning on the electric fuel pumps but leaving carburetor heat off unless icing conditions existed. The engine failure checklist specified turning on electric fuel pumps, pushing mixture to full rich, applying carburetor heat, and checking the ignition switch.
The recorded temperature and dew point at the destination airport near the time of the accident were 55°F and 24.8°F, respectively, giving a relative humidity of 30.45%. Per the carburetor icing probability chart in FAA Special Airworthiness Information Bulletin CE-09-35, these conditions were favorable for the formation of carburetor icing at glide and cruise power.