Raytheon Aircraft Company A36 accident near Mountainaire, Arizona, May 28, 2013

The NTSB's narrative final · quoted from the NTSB record

The pilot had purchased the Beechcraft airplane about 18 months before the accident and based it at his home airport, which was located at an elevation of about 80 ft mean sea level (msl). The pilot flew the Beechcraft to an airport that was at an elevation of about 7,100 ft msl. A few days after his arrival, he returned to the airport for his planned departure and spent about 15 minutes asking the fixed base operator owner, who was also a pilot, multiple questions about the route to his next planned destination. According to the owner, he was surprised by the nature of the pilot's questions, his lack of basic aeronautical information knowledge for area restrictions, and his lack of formal planning for his flight. No witnesses reported anything unusual about the engine start or taxi. At the time the pilot was cleared by the air traffic control tower controller for takeoff, the airport density altitude was about 9,000 ft. No ground witnesses reported observing anything unusual with the takeoff, but a Cessna 172 pilot who was behind the Beechcraft reported that the Beechcraft's climbout was slow. Shortly after his own takeoff, about 75 seconds after the Beechcraft, the Cessna pilot asked the tower controller about the Beechcraft's situation and intentions because the Cessna was already well above the Beechcraft. This prompted the controller to ask the Beechcraft pilot if he needed assistance, and the pilot responded that he was climbing "very slowly" and would remain near the airport. Shortly after that, the Cessna pilot saw the Beechcraft impact trees. The accident site was about 3 miles southeast of the airport at an elevation about 300 ft below that of the departure airport. A postimpact fire obscured or destroyed a significant amount of evidence. Review of the Beechcraft's published performance data revealed that, for the given conditions, the airplane should have been able to successfully depart the airport and climb at a rate of about 500 feet per minute. Most of the engine components and all of the propeller components that survived the accident, displayed no evidence of preimpact mechanical deficiencies. The engine cylinder conditions were indicative of a history of generally lean operation. In addition, the No. 5 cylinder exhaust valve's appearance was consistent with excessively lean operation for an undetermined period of time, and the fuel injector nozzle for that cylinder was found to be partially occluded. Excessively lean operation will reduce engine power output, and will manifest itself as abnormally high exhaust and cylinder head temperatures and possible engine roughness. Further, if the No. 5 cylinder's injector was occluded for the flight, it would have resulted in overly lean operation of and reduced power output from that cylinder, yielded higher exhaust and cylinder head temperatures, and likely manifested itself as engine roughness. (Some witnesses close to the impact site reported that the engine was making "popping" noises.) Although the airplane was equipped to monitor, display, and record temperatures for each cylinder, it could not be determined whether the pilot monitored that display, and fire damage prevented the recovery of that data from the engine monitor. Further, there was insufficient evidence to determine the source of the injector's occlusion, quantify its effects on engine power output, determine its relation to the condition of the exhaust valve, or determine if it was present for the takeoff or an artifact of the postimpact fire. Although the engine was developing power at impact, there was insufficient evidence to quantify the actual power output for the climb or at the time of impact. There was also insufficient evidence to determine whether the pilot ensured that the throttle and propeller controls were set to and remained in their appropriate positions for the departure or whether the pilot adjusted the mixture properly (not overly lean). It is likely that the pilot lifted off prematurely at a speed lower than the prescribed value and was unable to accelerate or climb the airplane once it exited the ground effect regime. Because the surrounding terrain and the impact point were lower than the elevation of the airport, the pilot was able to continue to fly the airplane before crashing. This scenario is at least partially corroborated by the pilot's reported lack of preparation for the flight, which could have included a lack of performance planning. This scenario is also partially corroborated by the observed repetitive minor banking of the airplane, which often occurs when an airplane is flying very slowly. A premature liftoff or a climb attempt at a speed significantly below the prescribed value would place the airplane in a situation where the power required for level flight was very near to or exceeded the available power. A recovery would require the pilot to lower the nose in order to accelerate the airplane to obtain a positive rate of climb. Such an action is counterintuitive when low to the ground and requires accurate problem recognition, knowledge of the correct solution, and sufficient terrain clearance to accomplish. During the departure, the pilot reduced his options by deciding to turn to the east instead of continuing straight ahead to the south. Review of topographic data revealed that a four-lane highway was located just beyond the south end of the runway, and was situated in a north-south valley that descended to the south. However, instead of tracking over that highway, which could have been used as an off-airport emergency landing site, and its descending valley, which provided increasing terrain clearance, the pilot opted to turn east, toward higher, wooded terrain. Although that turn was consistent with both a left traffic pattern (in order to remain close to the airport as the pilot reported to the air traffic controller), and toward the pilot's on-course heading, by making that turn, the pilot reduced the likelihood of a partially or fully successful outcome to the flight.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.