Missoula, MT, USA
N1940J
BUCKER JUNGMEISTER BU 133
The airline transport pilot purchased the airplane the day before the accident and was flying it across the country to his home airport. After landing at the accident airport, the pilot spoke on the telephone to a mechanic familiar with the airplane. The pilot reported to the mechanic that, after both of his earlier refueling stops, during the take climb, fuel had entered the cockpit, but after flying for a while, it stopped. The pilot stated that someone was helping him inspect the fuel system, but they were not able to find anything wrong. The mechanic stated that it sounded like a fuel venting problem and recommended that the pilot not fly the airplane until the issue was resolved. The pilot told the mechanic that he needed to get the airplane home and said that he was going to depart with all electrical power off. On the initial takeoff climb, witnesses saw the airplane enter a steep right turn; this was consistent with the pilot attempting to return to the runway. After turning about 180°, the airplane stalled, entered a spin, and descended to ground impact. Upon impact, a fire erupted, which consumed most of the airplane. Although the pilot had told the mechanic that he had someone help him inspect the fuel system, no one was identified at the accident airport who reported helping the pilot inspect the fuel system or seeing the pilot or anyone else perform such an inspection. Therefore, it is likely that the pilot experienced the same fuel leakage problem on the accident takeoff that he had experienced after his previous refueling stops. Extensive postcrash fire damage to the fuel system prevented determination of the source of the fuel leak. The fuel selector was found in the "off" position. Because the pilot choses to take off with no electrical power, he was unable to communicate the reason for his turn to tower controllers. It is likely that the pilot was distracted by fuel entering the cockpit and failed to maintain adequate airspeed as he was returning to the airport to rectify the problem, which resulted in the airplane exceeding its critical angle of attack and an aerodynamic stall/spin. Toxicology testing identified 10% carbon monoxide in the pilot's specimens. This was likely due to the postcrash fire.
HISTORY OF FLIGHT On October 14, 2015, at 1510 mountain daylight time, a Bucker Jungmeister BU 133/C, airplane N1940J, crashed in a parking lot during the initial takeoff climb at the Missoula International Airport (MSO), Missoula, Montana. The pilot was fatally injured. The airplane was destroyed. The airplane was owned by the pilot, who operated the airplane under 14 Code of Federal Regulations Part 91 as a personal cross-country flight. Visual meteorological conditions prevailed for the flight that was destined for Alabama. No flight plan had been filed. The pilot purchased the World War II-era single-seat biplane the day before the accident. According to the former mechanic for the airplane, on the day of the accident, the previous owner contacted him to let him know that the airplane had been sold and that the new owner/pilot was having a problem with fuel running into the cockpit. The former owner asked the mechanic if he could call the pilot. The mechanic called the pilot and left a message. When the pilot called him back, the pilot stated that he had refueled at the Dalles, Oregon, airport. After takeoff, when the pilot lowered the nose, he was getting fuel on the floor and down the tubing on the side of the cockpit. He shut off all the electrical power and continued the flight; after a while, the problem went away. The pilot also experienced the same scenario when he refueled in Coeur d'Alene, Idaho. The mechanic told the pilot that it sounded like the fuel tank was not venting properly and that it was forcing out fuel until air could get into the tank. The pilot said that someone at the airport in Missoula was helping him inspect the fuel system, but they were not able to find anything wrong. The mechanic suggested that the pilot ask them to check the vent system. The pilot told the mechanic that he was going to call the tower and leave Missoula with all electrical power off. The mechanic suggested to the pilot that he not fly the airplane until the problem was fixed. The pilot reported that he had to get to Alabama, or as far east as he could by October 16. The mechanic stated that they spoke for about 10 minutes, and he found out later that the pilot had crashed about 20 minutes after they had spoken. Witnesses located at Northstar Jet, the fixed base operator (FBO) at MSO where the pilot obtained fuel, reported that they had very little interaction with the pilot. The line crew employee reported that the pilot pumped his own fuel and spilled some fuel during the fueling process. The airplane was fueled with 14 gallons of fuel. None of the Northstar Jet personnel reported helping the pilot inspect the fuel system or seeing the pilot or anyone else perform such inspection. Several witnesses saw the airplane takeoff. A mechanic at another FBO stated that during takeoff from runway 25, the airplane appeared to have plenty of power and sounded good. Once airborne, the airplane made a hard-right turn with the bank angle increasing. A second witness at the same FBO stated that the airplane made a steep right bank and began to descend. A third witness reported that the airplane climbed quickly after rotation, and made an immediate right turn; the rate of climb decreased, and the airplane began to sink as it continued to turn right. After turning about 180°, the airplane "suddenly rolled about 90° to the right as the wing stalled." The airplane entered a spin and descended "almost straight down," to impact in the rental car lot at the airline terminal. Upon impact, a fire erupted. Another witness stated that he was on the west end of the airport when he saw the airplane about 80 ft above ground level (agl) enter a hard-right turn, then the airplane descended and impacted the ground. According to this witness, the engine sounded like it was "powering up." A witness at the eastern end of the rental car parking lot stated that the engine was running at the time the airplane impacted the ground. PERSONNEL INFORMATION No personal logbooks were made available to the National Transportation Safety Board (NTSB). A review of the pilot's Federal Aviation Administration (FAA) airman medical records on file at the Airman and Medical Records Center in Oklahoma City, Oklahoma, revealed that the pilot was issued a second-class medical certificate on June 4, 2015. He reported 11,200 total flight hours with 150 hours accrued in the past 6 months. AIRCRAFT INFORMATION The last maintenance performed on the airplane was an annual inspection completed on June 12, 2015, at an airplane total time of 2,038.9 hours. The airplane was powered by a radial piston Warner Aircraft Engines Scarab 165, serial number 2031A; at the time of the annual inspection, the engine total time was recorded as 909.4 hours, with 32.7 hours since major overhaul. METEOROLOGICAL INFORMATION AIRPORT INFORMATION WRECKAGE AND IMPACT INFORMATION Investigators from the NTSB and an inspector from the FAA responded to the accident site. The entire airplane came to rest in the long-term parking lot on airport property, and most of the airplane was consumed by the postcrash fire. MEDICAL AND PATHOLOGICAL INFORMATION The Montana Department of Justice Forensic Science Division, Missoula, Montana, conducted a post mortem examination on the pilot. The cause of death was listed as blunt force trauma with thermal injuries and smoke inhalation. The FAA Bioaeronautical Sciences Research Laboratory in Oklahoma City, Oklahoma, performed forensic toxicology on specimens from the pilot. The results were negative for cyanide, ethanol, and drugs of abuse. The results were positive for carbon monoxide, which was detected at 10% in heart blood. TEST AND RESEARCH According to Northstar Jet personnel, two of their company airplanes had refueled before the accident airplane via the same truck that had fueled the accident. The two airplanes and the fuel truck were taken out of service, and the fuel was tested with no discrepancies noted. A visual engine examination revealed no obvious mechanical problems. The engine could not be manually rotated because of engine displacement due to impact forces. The number three cylinder had separated from the crankcase and exposed the inside of the engine. The engine accessory components had sustained fire damage. Both the left and right magneto remained attached at their respective mounting pads. The left magneto was manually rotated and spark was observed at the ignition leads. The right magneto had sustained fire and impact damage, and the magneto was disassembled with no mechanical malfunctions noted. The fuel system was subjected to and compromised by the postcrash fire. The fuel selector was removed from the airframe, and upon visual examination, no obvious mechanical deficiencies were noted. Compressed air was blown into each of its selector positions, 1,2, and both; no air escaped from the openings. The fuel selector was then manually moved through each of its positions, compressed air was blown into each position, and air was noted to come out of each fuel selector position.
The pilot’s failure to maintain adequate airspeed and his exceedance of the airplane’s critical angle of attack while executing a return to the runway after takeoff, which resulted in an aerodynamic stall/spin. Contributing to the accident was the pilot’s decision to take off with a known mechanical problem.
Source: NTSB Aviation Accident Database
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