History of Flight
On June 2, 2020, about 1333 Atlantic standard time, a Piper PA-23-250, N14181, was substantially damaged during takeoff from Fernando Luis Ribas Dominicci Airport in San Juan, Puerto Rico. The airplane was operated as a post-maintenance flight test under Title 14 Code of Federal Regulations Part 91. The airline transport pilot and one passenger were fatally injured, and a pilot-rated passenger was seriously injured.
The pilot-rated passenger, who occupied the right front seat and held a mechanic certificate, reported that the pilot taxied to runway 9 for an engine run-up with no discrepancies noted. After takeoff clearance, the pilot applied takeoff power, and the airplane immediately yawed left as if the left engine was not producing power. The pilot aborted the takeoff and regained control. The passenger attributed the yaw to left engine power loss but asked the pilot, who responded that the left landing gear strut had less nitrogen than the right. A partial transcript of pilot-ATC communications included the statement "…I think it's a low tire." After exiting the runway, the left engine quit at idle; the pilot restarted it with difficulty and taxied to the ramp.
At the ramp, the pilot directed the passenger to inspect the landing gear. The passenger noted the left strut had more extension than the right, contrary to the pilot's expectation. The pilot then performed an engine run-up, including magneto check and propeller cycling, with no discrepancies detected. The pilot requested taxi clearance to runway 09 again.
On the second takeoff, the airplane yawed left when power was applied. The pilot applied right rudder, yoke to the right, and back pressure. During takeoff, the pilot struggled to maintain control as the airplane drifted left. The pilot raised the landing gear selector but the passenger did not recall seeing a green light. The airplane did not climb normally; the passenger estimated 100 feet per minute.
Security video from a marina showed the airplane in a near wings-level, nose-up attitude on the upwind leg, with a landing gear visible. The airplane then rolled left into an inverted, nose-low attitude and impacted the water. No parts separated in flight. After impact, the passenger was knocked unconscious, regained consciousness, and exited after the airplane submerged.
An in-flight video from a passenger's PED showed the instrument panel during climb, with both pilot hands on yoke and a right roll command. Left engine controls appeared full forward. Airspeed was between 90-100 mph. The engine monitor showed near-zero fuel flow for the left engine and low fuel pressure; left engine rpm was 1,000-1,500, right engine rpm near top of green arc.
Personnel Information
The pilot held a mechanic certificate with airframe and powerplant ratings issued September 18, 2008.
Aircraft Information
The landing gear and flaps were hydraulically controlled by an engine-driven pump on the left engine. According to the FAA-approved Airplane Flight Manual, in the event of left engine failure, gear and flaps should be retracted using the emergency hand pump, requiring about 50 strokes. Published minimum controllable single-engine airspeed was 80 mph; best single-engine rate of climb airspeed was 102 mph.
The airplane was equipped with a Garmin GTN 650, Garmin GPSMap 696, and JPI EDM 960 engine monitor. The GTN 650 had no data recording; the GPSMap 696's last recorded flight was April 4, 2019. The engine monitor recorded two sessions on the accident date; the accident flight data showed left engine rpm 1,000-1,300 and right 600-800 rpm, indicating no takeoff data. Prior flights recorded about 2,300 rpm for both engines. Last recorded fuel level in the left outboard tank was 9.9 gallons.
Wreckage and Impact Information
The wreckage was recovered the next day. Fuel tanks were drained without FAA presence. Examination revealed extensive impact damage; the left wing separated at the root. All landing gears were extended. Flight controls showed no preimpact failure. The hydraulic flap actuator piston was extended about 7 inches (flaps retracted). Rudder trim jackscrew corresponded to neutral to slight nose-right trim. Stabilator jackscrew corresponded to full nose-up trim.
Examination of the left-wing fuel system (selector, hoses, strainer, tank, electric pump) found no preimpact failures. Left engine propeller and mixture controls had continuity except cuts at wing root. Throttle cable continuity was confirmed to the wing root area; the ball screw connecting to fuel servo was fractured, consistent with overstress in bending.
Manual rotation of left propeller confirmed continuity. Compression was felt at all cylinders. Magnetos produced spark. Engine-driven fuel pump actuated normally. Fuel servo inlet screen was clear; manifold valve diaphragm flexible; three injectors clear, three with some blockage. Fuel hoses contained 100LL with no water. Propeller governor was clean and pumped oil. Right engine controls and engine showed no preimpact failure.
Both propellers remained attached; blades secured. No evidence of failure; left propeller blades were at or near low pitch position.
Additional Information
Fueling records indicated the airplane was fueled with 47.5 gallons of 100LL about 2 hours prior, with both inboard tanks topped off. The pilot was present during fueling and checked fuel at each nacelle. Another airplane fueled from the same truck flew without fuel issues.
Tests and Research
Fuel supply hoses had no internal obstructions or leaks. Examination of the left fuel servo at a certified repair station revealed the nylon throttle stop was missing, allowing the throttle plate to fully close instead of a 0.006-inch gap. When setting the gap, a gap greater than 0.006 inch was noted at the throttle stop. During operational testing, material consistent with sand flowed from the unit. At a test point simulating takeoff (throttle wide open, mixture full rich), the unit flowed about 69% of the minimum required value. Partial disassembly revealed contamination between mixture and idle valves. After removing contamination, the unit flowed within specification. The contamination was not identified. Operational testing of fuel injector nozzles showed slight out-of-tolerance conditions; manifold valve testing could not be performed.