CEN15FA060

The pilot's failure to maintain adequate airspeed during a forced landing following a total loss of engine power due to fuel starvation, which resulted in the airplane exceeding its critical angle of attack, and an aerodynamic stall at a low altitude. Contributing to the accident was the pilot’s improper fuel management.

The commercial pilot was on a cross-country flight when the airplane encountered deteriorating weather conditions. A surviving passenger reported that the pilot decided to divert to a nearby airport. The airplane experienced a loss of engine power in the airport traffic pattern shortly after the pilot extended the landing gear during the base-to-final turn. The pilot was able to restore engine power briefly by advancing the throttle, but the engine quickly experienced a total loss of power. The passenger stated that the airplane entered an aerodynamic stall about 250 ft above the ground. The airplane subsequently impacted terrain in a near-level attitude. The pilot likely failed to maintain adequate airspeed following the loss of engine power, which resulted in the airplane exceeding its critical angle of attack and a subsequent aerodynamic stall at a low altitude. A postaccident examination did not reveal any mechanical malfunctions that would have precluded normal engine operation; however, the right main fuel tank was void of any usable fuel, and the left main fuel tank contained about 1.5 gallons of usable fuel. Additionally, no fuel was recovered from the supply line connected to the fuel manifold valve, and only trace amounts of fuel were recovered from the engine-driven fuel pump outflow line. A first responder reported that the main fuel selector was positioned to draw fuel from the auxiliary fuel tanks. Although placarded for use during level flight only, both auxiliary fuel tanks contained sufficient fuel to maintain coverage over their respective outlet ports during maneuvering flight, and would have provided fuel to the engine. As such, it is likely that the main fuel selector was positioned to draw fuel from the right main fuel tank when the airplane initially experienced a loss of engine power due to fuel starvation. The pilot then likely switched to the right auxiliary fuel tank while attempting to restore engine power; however, there was likely insufficient time and altitude to re-establish fuel flow to the engine. Although the airplane had experienced an alternator malfunction during the previous flight, a possible charging system failure would not have affected engine operation during the accident flight.

The Jesse Viertel Memorial Airport (VER), located about 3 miles southeast of Boonville, Missouri, was served by a single runway: 18/36 (4,000 ft by 75 ft, asphalt). The airport elevation was 715 ft msl. Four personal electronic devices were recovered at the accident site and sent to the National Transportation Safety Board (NTSB) Vehicle Recorders Laboratory in Washington D.C. for potential non-volatile memory (NVM) data recovery. An examination of the pilot's Apple iPad Mini revealed it had the ForeFlight application installed. The application's map page displayed route information for a flight from SUS to MKC. The specifics of the flight included a calculated distance of 186 nautical miles between SUS and MKC, a calculated course of 281 degrees magnetic, an estimated time enroute of 1 hour 10 minutes (calculated using 160 knots true airspeed without the effect of winds aloft), and an calculated fuel consumption of 17.4 gallons. There was no track history for the accident flight; the option to record a track history was not selected for the accident flight. The most recent track history was for a flight completed on August 24, 2014. Further examination of the device established that the text messages, photos, and internet browser history did not contain any information pertinent information to the investigation. According to a passenger, the pilot had used the iPad Mini to navigate during the accident flight. An examination of a passenger's Samsung Galaxy S III smartphone revealed that there were four photos taken during the accident flight between 0826:47 and 0831:51. During the five-minute period of recovered photos, the observed cloud cover near the airplane increased from clear skies to low-level, overcast stratocumulus clouds. Further examination of the device established that the text messages did not contain any information pertinent information to the investigation. The remaining two devices, a Motorola Droid Smartphone and an Apple iPod Touch, did not contain any data pertinent to the accident investigation. According to available air traffic control data, the accident flight was at least 1 hour 17 minutes in duration. According to the airplane's owner manual, the expected fuel consumption rate at 2,500 ft msl and 77-percent power was 16.1 gallons per hour. At 77-percent engine power, the accident airplane would have used at least 20.7 gallons of fuel; however, engine operation above 77-percent power and/or insufficient leaning would have consumed additional fuel. On December 1, 2014, at the request of the Cooper County Coroner, the Boone/Callaway County Medical Examiner's Office located in Columbia, Missouri, performed an autopsy on the pilot. The cause of death was attributed to multiple blunt-force injuries sustained during the accident. The FAA's Civil Aerospace Medical Institute located in Oklahoma City, Oklahoma, performed toxicology tests on samples obtained during the autopsy. The toxicological test results were negative for carbon monoxide, ethanol, and all drugs and medications. A postaccident examination revealed that the airplane impacted a harvested soybean field on a 305-degree magnetic heading. The initial point-of-impact consisted of three parallel depressions in the field that were consistent with the spacing of the airplane's three landing gear. The main wreckage was located about 24 ft from the initial point-of-impact in an upright position. The accident site was located along the extended runway centerline about 0.4 miles south of the runway 36 threshold. Flight control continuity was confirmed from the cockpit controls to the individual flight control surfaces. The wing flaps were about 1/2 of their full deflection. The landing gear selector switch was in the DOWN position; however, all three landing gear assemblies had collapsed during the impact sequence. The main fuel selector was in the OFF position; however, a first responder had moved the fuel selector from the AUX position to OFF during rescue efforts. Additionally, the first responder turned the engine magneto/ignition key to OFF and disconnected the battery terminals after hearing the sound of an electric motor located under the floorboards. (The sound of an electric motor was later identified to be the electrohydraulic motor for the landing gear extension/retraction system.) The auxiliary fuel tank selector was in the RIGHT position. The electrical master switch was in the ON position. The digital transponder was in the ON/Altitude Encoding position. The electric fuel pump switch was in the OFF position. There were no anomalies identified during functional tests of the electric fuel pump and the aerodynamic stall warning system. The postaccident airframe examination revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation. The airplane was equipped with two inboard main fuel tanks and two outboard auxiliary fuel tanks. The reported capacity of each main fuel tank was 19 gallons, of which 15.5 gallons were usable per tank. The reported capacity of each outboard auxiliary fuel tank was 17 gallons; however, according to a cockpit placard, the auxiliary tanks were for use during level flight only. A visual examination of the four fuel tanks revealed no damage or evidence of a fuel leak. The left main tank contained about 5 gallons of fuel. The right main tank contained 3-1/2 pints of fuel. The left auxiliary tank was near its 17-gallon capacity. The right auxiliary tank contained about 11 gallons of fuel. There was no fuel recovered from the supply line connected to the inlet port of the engine-driven fuel pump; however, the gascolator drain had fractured during impact and there was evidence of a small fuel spill underneath the gascolator assembly at the accident site. There was a trace amount of fuel recovered from the engine-driven fuel pump outflow line. There was no fuel recovered from the fuel supply line connected to the fuel manifold valve. The engine remained partially attached to the firewall by its engine mounts and control cables. Mechanical continuity was confirmed from the engine components to their respective cockpit engine controls. Internal engine and valve train continuity was confirmed as the engine crankshaft was rotated. Compression and suction were noted on all cylinders in conjunction with crankshaft rotation. The upper spark plugs were removed and exhibited features consistent with normal engine operation. Both magnetos provided spark on all leads when rotated. There were no obstructions between the air filter housing and the fuel control unit. The three blade propeller and crankshaft flange had separated from the engine. The propeller blades exhibited minor burnishing of the blade face and back. One blade appeared straight. Another blade exhibited a shallow S-shape bend along its span. The remaining blade was bent aft about midspan. The postaccident examination revealed no evidence of a mechanical malfunction or failure that would have precluded normal engine operation. The National Weather Service (NWS) Surface Analysis Chart for 0900 CST depicted a strong cold front immediately east of the accident site. The front stretched across Missouri between the departure airport and the planned destination. The cold front was associated with a defined wind shift and low stratiform clouds behind the front. There were several weather stations located near the accident site that had surface visibility restrictions in fog and mist. Weather radar imagery did not depict any significant weather echoes in the area of the accident site; however, the weather radar did detect a fine line of very light intensity echoes associated with the cold front. Satellite imagery depicted a band of low stratiform clouds extending over the accident site westward through the Kansas City area. The cloud band was located along and behind the cold front. The NWS 12-hour Surface Prognostic Chart depicted a cold fron