Accident Overview
On June 8, 2024, at 1016 eastern daylight time, a Piper PA28-235, registration N15363, sustained substantial damage during a forced landing near Zephyrhills, Florida. The airplane was conducting an instructional flight under Title 14 Code of Federal Regulations Part 91. The pilot and flight instructor reported no injuries.
Flight and Event Sequence
The flight instructor stated the flight was intended for instrument approach practice. According to both pilots, no anomalies were observed during preflight, taxi, or engine runup. After a normal takeoff, when the airplane reached about 300 feet above ground level, the engine partially lost power. The pilot, unable to maintain climb, reduced power and initiated a forced landing in grass off the departure end of the runway. During the landing, the airplane impacted a fence, damaging the left wing and fuselage. The pilot reported that the left auxiliary fuel tank was selected during the accident takeoff.
Engine Data Recorder Information
The airplane was equipped with a Dynon primary flight display that recorded engine parameters. Data showed a sharp increase in engine speed and manifold pressure at 1015:45, consistent with full power. Engine speed peaked at 2,554 rpm and manifold pressure at 28 inches of mercury at 1015:56, remaining steady until 1016:10. Then, within 6 seconds, rpm dropped to 1,399 and manifold pressure to 20.8 inches of mercury. Subsequent fluctuations included brief increases to about 2,500 and 2,560 rpm, followed by drops to 1,841 and 1,170 rpm. The engine speed then rose to 2,370 rpm at 1016:13, then reduced to about 1,000 rpm until shutdown at 1016:24. Manifold pressure oscillated correspondingly. Fuel flow increased to a maximum of 18.8 gph at 1015:58, then steadily decreased. At the first power reduction, fuel flow was 10.3 gph; during fluctuations, it varied between 11.2 and 6.9 gph. Total engine operation time for the accident flight was about 12 minutes.
Postaccident Examination
Postaccident inspection revealed the left auxiliary fuel tank was breached and empty. The fuel pickup screen from that tank was clear and unobstructed. Left and right main fuel tanks were undamaged and nearly full of fuel consistent with 100LL avgas. The right auxiliary fuel tank had minor damage at the quick drain and a secure cap but was empty. The cockpit fuel selector rotated normally with distinct detents and was found in the left auxiliary position. Low-pressure air blown through the fuel strainer outlet confirmed the left auxiliary tank lines were unobstructed with no breaks. The fuel strainer bowl contained large debris particles and contamination on the screen, though the screen was not obstructed.
Engine continuity was established; manual rotation produced thumb compression and suction in all six cylinders. Top spark plug electrodes showed normal wear. A carburetor bowl fuel sample was clear and consistent with 100LL avgas. The engine was prepared for an on-airframe test run: fuel system primed with the boost pump and engine primed manually. The engine started without hesitation. A magneto drop check yielded acceptable results per Lycoming Service Instruction 1132B. The engine ran for about 25 minutes at various rpm settings from idle to full power, selecting left and right main fuel tanks. The propeller control was seized and immovable in the cockpit, but the governor maintained full throttle rpm. No roughness, stumbling, hesitation, or power loss occurred.
After shutdown, rocker box covers were removed; valves, springs, and rocker arms showed normal operation and lubrication. The propeller control cable rod end was removed from the governor, allowing normal governor arm movement. The control cable remained seized, and its rod end was severely corroded. No leaks were found around the fuel pump, carburetor, or fuel lines. The carburetor inlet screen had no contaminants. Disassembly of the fuel pump revealed corrosion on several internal components.
The carburetor underwent static pressure testing; bowl, floats, and float valve operated normally. The accelerator pump discharged fluid but weakly and in low volume. Flow bench testing showed no anomalies preventing normal engine operation. Disassembly revealed significant debris and corrosion in the carburetor bowl, with loose particulates about 1/8 inch long. The main fuel nozzle, nozzle well, and mixture metering sleeve contained particulates. The accelerator pump had normal wear; the metal check valve ball was missing from its housing, with no trace found. The retaining clip was severely corroded.
Maintenance History
According to the PA-28-235 service manual current at the last annual inspection, the carburetor bowl should be drained and the screen inspected during each annual/100-hour inspection. The last annual inspection was on March 1, 2024, at tachometer time 1,753.0 hours, which included an avionics panel upgrade adding a primary flight display and sensors. The previous annual inspection on January 24, 2023, recorded cleaning and flushing of fuel lines after replacing the electric fuel pump. On October 20, 2021, the carburetor was removed, and the bowl and inlet screen were cleaned. Precision Airmotive Corporation Service Bulletin MSA-3 recommends float carburetors be overhauled at engine overhaul or 10 years since service. Logbooks indicated the carburetor was overhauled and reinstalled on January 20, 2014. The engine logbook showed the last engine overhaul occurred on March 9, 1992. Lycoming Service Instruction 1009BE recommends engine overhaul every 2,000 hours or 12 calendar years, whichever occurs first, to mitigate age-related deterioration including corrosion.
Conclusion
The investigation documented a partial engine power loss during climb, leading to a forced landing with fence impact. Engine data and postaccident examinations revealed fuel system contamination and corrosion, particularly within the carburetor, as well as a seized propeller control cable. No probable cause was stated in the source.