CEN22LA391

The pilot and pilot-rated-passenger were conducting an instrument approach when there was a sudden and total loss of fuel flow to the engine as the airplane descended through 1,200 ft mean sea level (msl). The pilot was unable to restore engine power after he increased the throttle and mixture controls, checked both magnetos, and engaged the starter motor. Based on recorded engine data, there was no fuel flow to the engine for the remainder of the flight. The pilot declared an emergency with the air traffic controller and made a forced landing in a grass area short of the runway. The airplane clipped trees and bounced during the forced landing. The fuselage and both wings were substantially damaged during the accident. The engine examination revealed no evidence of a preimpact mechanical malfunction or failure that would have precluded normal operation. There was no evidence of a fuel leak inside the engine compartment or outside on the lower cowl and fuselage skins. The push-pull throttle, mixture, and propeller controls remained intact and functioned as designed. The airframe fuel filter and the inlet screen to the throttle and control unit remained wet with fuel and were free of particulate contamination. Fuel was found in the return lines. Additional examination and testing of the throttle and control unit, engine-driven fuel pump, fuel distribution valve, and fuel flow transducer did not reveal any anomalies that would have resulted in a sudden and total loss of fuel flow to the engine during the flight. The postaccident examination revealed usable fuel in each wing tank. Although the fuel selector was found in the OFF position, it could have been repositioned by the pilot or first responders to secure the airplane’s fuel system after the accident. Additional review of the recorded engine data did not reveal erratic engine operation that is typically associated with a loss of engine power due to fuel starvation or exhaustion. Alternatively, if the pilot or pilot-rated-passenger inadvertently repositioned the mixture control to cutoff during the descent, it would have resulted in the sudden and total loss of fuel flow that was recorded by the engine monitor. However, based on the pilot’s statement, he attempted to restore engine power by increasing the throttle and mixture controls. With a windmilling propeller, the engine-driven fuel pump would have provided appreciable fuel flow to the engine if the mixture control was forward of the cutoff position. The reason for the sudden and total loss of fuel flow to the engine could not be determined.

According to the Beech F33A Pilot Operating Handbook, the standard 50-gallon fuel system consists of two 25 gallon (22 gallons usable) wing tanks. The pilot reported that the airplane departed on the 13-minute flight with 34 gallons of fuel available. On August 18, 2022, about 0853 central daylight time, a Beech F33A airplane, N17747, was substantially damaged when it was involved in an accident at the Baton Rouge Metropolitan Airport (BTR), Baton Rouge, Louisiana. The pilot and pilot-rated passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the purpose of the flight was to remain in the airport traffic pattern and practice landings; however, shortly after takeoff he determined instrument meteorological conditions prevailed and requested an instrument flight rules clearance to return to the airport for a full-stop landing. The pilot was issued radar vectors to join the instrument landing system (ILS) runway 22R approach. After aligning with the localizer inbound to the runway, the pilot extended the landing gear and selected 15° of wing flaps. The pilot reported that the airplane was high on the glideslope when it descended below the clouds about 1,500 ft msl. He reduced engine power and decreased airplane pitch to increase the airplane’s descent rate. When the airplane was about 1,000 ft msl he further reduced engine power, but after a “small bump” the airplane had a total loss of engine power that was confirmed by referencing the engine intake manifold pressure gauge. The pilot was unable to restore engine power after he increased the throttle and mixture controls, checked both magnetos, and engaged the starter motor. The pilot declared an emergency with the air traffic controller and made a forced landing in a grass area short of runway 22R. The airplane clipped trees and bounced during the forced landing. According to engine monitor and airplane track data, at 0852:07, there was a sudden and total loss of fuel flow to the engine with a corresponding decrease in exhaust gas temperature (EGT) for all six cylinders, as depicted in Figure 1. The loss of engine power occurred as the airplane was descending through 1,200 ft msl, as depicted in Figure 2. After the total loss of engine power, the engine intake manifold pressure increased to 30.70 inHg, consistent with a full-forward throttle position with a windmilling propeller. Based on the recorded engine data, there was no fuel flow to the engine for the remainder of the flight. Figure 1. Plot of engine speed, EGT, fuel flow, and manifold pressure. Figure 2. Plot of altitude, ground speed, and vertical speed. The airplane came to rest nose down in a grass area located outside of the airport perimeter fence, about 975 ft before the runway 22R threshold and 550 ft left of the extended runway 22R centerline. The nose landing gear collapsed during the hard landing. The fuselage and both wings weresubstantially damaged. The engine remained attached to the engine mounts. The propeller remained attached to the engine crankshaft flange. The push-pull throttle, mixture, and propeller controls remained intact and functioned as designed. The cockpit fuel selector and electric fuel pump were found in the OFF position. The right wing tank contained about 15 gallons of fuel, and the left wing tank contained about 6 gallons of fuel. There was no evidence of a fuel leak inside the engine compartment or outside on the lower cowl and fuselage skins. The airframe fuel filter and the inlet screen to the throttle and control unit remained wet with fuel and were free of particulate contamination. Fuel was found in the return lines. The engine-driven fuel pump drive coupling was found intact. The top spark plugs exhibited features consistent with normal engine operation. Internal engine and valvetrain continuity were confirmed as the engine crankshaft was rotated through the propeller. Compression and suction were noted on all six cylinders in conjunction with crankshaft rotation. Both magnetos produced spark on all leads when the crankshaft was rotated. The ground wire (P-lead) for the left magneto was found broken. The engine oil and oil filter were not contaminated with metal or debris. The engine examination revealed no evidence of a preimpact mechanical malfunction or failure that would have precluded normal operation. Additional examination and testing of the throttle and control unit, engine-driven fuel pump, fuel distribution valve, and fuel flow transducer did not reveal any anomalies that would have resulted in a sudden and total loss of fuel flow to the engine during the flight.