WPR11LA080

The pilot's failure to recognize the onset of and to prevent an aerodynamic stall at low altitude. Contributing to the accident were the manufacturer’s conflicting guidance about the power setting for takeoff and the pilot’s decision to conduct a partial-power takeoff.

The owner/pilot of the experimental amateur-built kit airplane was cleared by the air traffic controller to take off and remain in the traffic pattern for practice. Witnesses reported that the airplane climbed to about 200 feet above the runway before it banked sharply to the right and descended rapidly to ground impact. The impact location was offset about 300 feet from the runway centerline and was about 2,400 feet down the 7,150 foot long runway. The airplane motion, trajectory, and impact angle were consistent with an aerodynamic stall. The wind was calm, the density altitude was about 1,340 feet, and the airplane was about 380 pounds below its maximum gross weight of 1,350 pounds. Several days after the accident, the pilot stated that he intentionally attempted to take off using partial engine power. The kit manufacturer's published guidance for the airplane contained conflicting information regarding the amount of power to be used for takeoff. The checklist section specified full power for takeoff. In contrast, the "Flight Tips" section instructed "new" pilots to "restrict take-off power to about 75% of full power" but did not provide any elaborating information. The guidance specified climb speeds between 45 and 65 mph and a clean power-off stall speed of 38 mph. The airplane was not equipped with either a stall warning or angle-of-attack indication system, and it was not required to be so equipped. Had the pilot recognized and correctly reacted to the impending stall, either by adding power, pushing the airplane nose down, or both, it is likely that the accident would not have occurred. The investigation was unable to determine the accuracy of the airspeed indication system or the actual stall speeds or stall characteristics of the airplane.

HISTORY OF FLIGHT On December 23, 2010, about 1421 mountain standard time, an experimental amateur-built Kitfox 4, N95FT, impacted terrain on airport property shortly after takeoff from Glendale Municipal Airport (GEU), Glendale, Arizona. The owner-pilot received serious injuries. The airplane was substantially damaged. The personal flight was operated under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. According to the air traffic control tower (ATCT) controller, the pilot had radioed for takeoff clearance, and requested clearance to remain in the traffic pattern for takeoff and landing practice. The controller approved the request, and cleared the flight to depart from runway 1. The controller stated that when the airplane was "approximately 2,000 feet down the runway," at an altitude of about 150 to 200 feet above ground level (agl), it was observed to be "wobbling," and then "corrected" its motion. Other witnesses reported that the initial climb "didn’t look right," that the airplane climbed to about 250 feet agl, and then appeared to "crab to the left." The controller and the other witnesses uniformly reported that the airplane turned and banked to the right, and then descended steeply to the ground. The airport duty operations manager arrived on the scene within minutes of the accident. The manager stated that the pilot was conscious and coherent, and that he stated to the manager that he had a "problem climbing." Emergency personnel extracted the pilot from the wreckage, and he was subsequently airlifted to a local hospital. PERSONNEL INFORMATION According to Federal Aviation Administration (FAA) records, the pilot held a private pilot certificate with an airplane single-engine land rating, and a repairman certificate for the accident airplane. His most recent FAA third-class medical certificate was issued in May 2010. Review of the pilot's logbook indicated that he began flying in 1982, and that his most recent flight review was completed in July 2009, in a Cessna 150 airplane. That flight review was the final entry in the pilot's logbook. In his accident report for this most recent accident, the pilot reported that he had a total flight experience of about 350 hours, including 65 hours in the accident airplane make and model. Communications with the pilot's family members indicated that due to the accident, he was hospitalized for about 2 months and underwent multiple surgeries. National Transportation Safety Board (NTSB) records indicated that in March 2003, also near GEU, the same pilot experienced a bird strike in the same airplane, which resulted in an off-airport forced landing, and substantial damage to the airplane. That accident was assigned NTSB accident number LAX03LA104. On his reporting form for that previous accident, the pilot indicated that he had a total flight experience of about 761 hours, including 3.8 hours in the accident airplane make and model. The discrepancy between the reported flight experience values could not be reconciled. AIRCRAFT INFORMATION The airplane, serial number 1557, was a kit-built, two-seat, high-wing, conventional gear configuration of tube-and-fabric construction. According to FAA records and documentation provided by the pilot, the airplane was built by the pilot in 2007. According to the pilot's reporting form from his previous accident in the airplane, it was built in 2003 by "Mel Tower." The date and manufacturer discrepancies could not be reconciled. The airplane was equipped with a Great Plains/Volkswagen converted automobile engine, with a reported rating of about 78 hp. The pilot reported that the airframe had a total time (TT) in service of 52 hours, and the converted engine had a TT of 51 hours, 48.5 hours since its most recent inspection and overhaul. The airplane kit manufacturer's published guidance (Kitfox Owner's Manual and Pilot's Operating Handbook, OM/POH) listed the maximum airplane gross weight as 1,350 pounds. The pilot reported that the gross weight at the time of the accident was approximately 970 pounds. The airplane was not equipped with either a stall warning system or an angle-of-attack indication system. FAA regulations did not require the installation of either of those systems on experimental amateur-built aircraft. METEOROLOGICAL INFORMATION The GEU automated weather observation taken about the time of the accident included calm winds; temperature of 16 degrees C; dew point of 7 degrees C; and a barometric pressure of 30.13 inches of mercury. Based on these conditions, the density altitude was calculated to be approximately 1,340 feet. AIRPORT INFORMATION According to FAA information, the airport elevation was 1071 feet above mean sea level (msl). The single paved runway was 100 feet wide and 7,150 feet long, and was designated as runway 1-19. The ATCT was situated approximately midfield, and was located approximately 950 feet west-northwest of the runway centerline. The ATCT was staffed and operating at the time of the accident. WRECKAGE AND IMPACT INFORMATION An FAA inspector arrived at the scene about 45 minutes after the accident. The wreckage was located about 300 feet east of the runway centerline, and 2,400 feet north-northeast of the runway 1 threshold, as measured along the runway axis. The inspector reported that aircraft damage and ground scars indicated that the right wing struck the ground first, and that the airplane came to rest standing on its nose. The front fuselage was crushed, and both blades of the wood propeller were splintered. The engine and wings were displaced from their design locations, but remained partially attached to the fuselage structure. Establishment of flight control continuity for the ailerons was precluded by the fuselage crush damage, but was confirmed for the remainder of the flight controls. The hour meter registered 54.5 hours, and the altimeter barometric pressure dial was set to 30.12 inches of mercury. ADDITIONAL INFORMATION Airplane Operating Procedures and Performance The OM/POH that was recovered from the accident airplane contained a number of procedural checklists for operating the airplane. The third item in the "Normal Take Off" checklist in the "Flight Procedures" section was "Throttle- FULL OPEN." The same entry was also listed in the "Max Performance Take Off" checklist. The "Kitfox Flight Tips" subsection in the "Flight Characteristics" Section of the OM/POH stated that the Kitfox was a "high performance airplane" and that "until you are thoroughly familiar with its flight characteristics…restrict take-off power to about 75% of full power." It also contained a "Caution" that stated "Pilots that are new to the Kitfox's performance can be startled at how quick (sic) the Kitfox can get airborn (sic) and the high rate of climb, so restrict take off power until you become familiar with the aircraft." The "Engine Failure After Take-Off" and "Forced Landing" checklists in the "Emergency Procedures" section each specified that an airspeed of 50 mph was to be used in the event of those situations. The Operating Limitations specified "No Power" stall speeds of 38 mph with flaps up, and 32 mph with full flaps. The section specified a "Best Rate of Climb Speed" of 55 to 65 mph, a "Best Angle of Climb" speed of 45 mph, and a "Best Glide Speed" of 50 mph. The airspeed indicator bore a "Kitfox" logo, and the scale extended from 0 mph to 120 mph. The scale was numbered in 10 mph increments, and hash marks denoted every 1 mph increment between 20 and 120 mph. A green arc extended from 38 mph to 105 mph; a yellow arc extended from 105 mph to 117 mph; and a red mark was faintly visible above 117 mph. No white arc was present on the indicator. The green and yellow arcs conformed to the speeds published in the manufacturer's