Accident Overview
On July 21, 2019, at 0920 central daylight time, a Cessna 305A airplane, registration N1831, experienced a complete loss of engine power during climb after departure from Houston Memorial Airport (M48) in Houston, Missouri. The pilot executed a forced landing to a field, during which the airplane struck trees and terrain. The private pilot was not injured, and the airplane sustained substantial damage. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a local personal flight in day visual meteorological conditions. A National Transportation Safety Board accident report was not submitted by the pilot.
Flight History
According to a Federal Aviation Administration inspector, the pilot was practicing takeoffs and landings to a full stop on runway 34. On the fourth takeoff, at approximately 500–600 feet above ground level, as the pilot retracted the wing flaps, the engine lost all power. The pilot verified the fuel selector was ON, applied carburetor heat, and set the throttle to full power. Moving the throttle control back and forth produced no change in engine output. During the forced landing, the pilot kept the wings level and intentionally stalled the airplane at treetop height to cushion the impact. The left wing and fuselage were substantially damaged.
Post-Accident Examination
The airplane's fuel system and carburetor had been modified under FAA supplemental type certificates SA281SW and SE264SW on July 18, 2019, at a tachometer reading of 503.7 hours. At the accident site, the tachometer indicated 508.4 hours. The left fuel tank contained about 3 gallons of 100 low-lead aviation fuel and was ruptured from impact; the right tank held about 10 gallons. Both wing root fuel gauges had red markings below approximately ¼ tank reading "NO TAKEOFF." The placarded usable fuel capacity was 36 gallons. A fuel sample from the belly drain showed no contamination.
The cockpit throttle, mixture, and carburetor heat controls were at mid-range travel. The magneto switch was set to BOTH, the fuel selector to OFF, and flaps were extended about halfway. One propeller blade was straight; the other was bent rearward about 30° near the tip.
A post-accident engine run was performed using an external fuel supply connected to the right wing root. The engine started normally, oil pressure rose to normal range, and magneto checks showed rpm drops of about 100 rpm. Carburetor heat application caused rpm drops of about 75 rpm. Due to propeller damage, engine speed was limited to 1,500 rpm. When the fuel selector was turned OFF, the engine sputtered and stopped within 30–45 seconds. A second start showed no effect from the primer; moving the mixture to IDLE-CUTOFF caused sputtering that ceased when advanced. A third start with the electric fuel pump on had no effect; the engine stopped after exhausting the external fuel supply. Air blown through fuel lines revealed no blockages.
Engine and Carburetor Inspection
The carburetor was removed and examined under NTSB supervision. It was a Marvel-Schebler MA-4-5 (part number 10-3859-1, serial number 4015585) by Facet. All components were secure. The float was non-metallic, blue, and free of fluid; its setting was 13/64 inch per specifications. The float and throttle valve moved without binding. The fuel inlet screen and carburetor bowl were clean. The nozzle assembly (part number 737, also applicable as 47-735) was unobstructed. The carburetor pump discharge valve lacked a spring, which was not in accordance with Volare Carburetors Service Bulletin SB-8 Rev B. No mechanical anomalies that would prevent normal operation were found.
Recorded ambient temperature and dewpoint at the time were conducive to serious carburetor icing at glide power.