Dickinson, ND, USA
N4040M
PIPER PA 12
The private pilot was attempting a takeoff from an industrial truck yard in 24- to 31-knot gusting headwind conditions. He performed a short field takeoff procedure with the wing flaps extended about halfway. As the airplane reached about 30 knots, the airplane's tailwheel lifted off the ground, then the pilot fully extended the flaps and the airplane became airborne. Shortly afterward, the right wing dropped. As he was recovering from the right bank, the pilot retracted the flaps from fully extended back to half extension and confirmed that the throttle was full forward. At that time, the airplane turned sharply to the right and descended into a parked trailer. A witness reported that, shortly after becoming airborne, the airplane entered a 35° right bank. The pilot corrected slightly; however, at that point, the airplane started a more abrupt climb, "snap rolled" to the right, and impacted the trailer inverted. The bank and roll to the right are consistent with an aerodynamic stall. A postaccident examination did not reveal any anomalies consistent with a preimpact failure or malfunction. The exact position of the wing flaps at the time of impact could not be determined. The dirt- and gravel-surfaced takeoff area was about 750 ft long and was rough and uneven. The uneven takeoff area may have reduced the airplane's acceleration during the takeoff ground roll, and the gusty wind condition may have contributed to the stall once airborne. In addition, given the limited takeoff distance available, the pilot may have rotated the airplane at a slower-than-normal airspeed, thereby increasing the possibility of an inadvertent stall. Additionally, the extension and retraction of the wing flaps during takeoff resulted in abrupt changes in the airplane's angle of attack and a subsequent aerodynamic stall, which precipitated the pilot's loss of control.
On November 22, 2017, at 1253 mountain standard time, a Piper PA-12 airplane, N4040M, was substantially damaged during an in-flight collision with a truck trailer immediately after takeoff from an industrial truck yard near Dickinson, North Dakota. The pilot sustained serious injuries and the passenger sustained minor injuries. The airplane was registered to and operated by the pilot as a 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed. The flight was not operated on a flight plan. The flight was originating at the time of the accident. The intended destination was the Sloulin Field International Airport (ISN), Williston, North Dakota.The pilot stated that during the accident takeoff, when the airplane attempted to climb out of ground effect, it banked to the right and the right-wing tip contacted the ground. The airplane continued to roll and came to rest on a truck trailer. He commented that the airplane might have encountered a wind gust which contributed to a right wing stall. He did not perceive anomalies with respect to the airplane during the accident takeoff. The pilot informed Federal Aviation Administration (FAA) inspectors that he did not feel that there was any hindrance to the airplane during the accident takeoff. The airplane was positioned at the east end of the truck yard to use all the available takeoff area. He set two notches of flaps and executed a short field takeoff procedure. The tail of the airplane lifted off the ground at about 30 knots, at which time he applied full flaps causing the airplane became airborne. Shortly afterward, the right wing dropped possibly due to a gust of wind. He responded by applying full left aileron and full left rudder to compensate. As he was recovering from the right bank, he retracted the flaps from full (third notch) to one-half (second notch) and confirmed throttle was full forward. At that time, the airplane tucked and turned sharply to the right. According to the passenger, the airplane was gaining speed during the takeoff run until it neared the west end of the maintenance building located in the yard. About 10 or 15 feet above the ground, the airplane seemed to come to a "complete dead stop" and subsequently rolled to the right. The pilot was able to recover momentarily; however, the airplane banked to the right again and ultimately impacted a truck trailer. A witness reported that the airplane became airborne about 400 feet into the takeoff run. Shortly afterward, when the airplane was about 6 feet above ground level, the right wing dipped to 35 or 40 degrees of bank. The pilot corrected, but the airplane remained in a 20-degree right bank. At that point, the airplane started a more abrupt climb, at which time the airplane "snap rolled" to the right and impacted a truck trailer inverted. He described the airplane attitude as "significantly nose up" and estimated the pitch angle as about 15-degrees angle of attack. The right-wing tip was about 6 feet off the ground when the airplane started the roll. The witness noted that the engine sounded as it if came to full power at the beginning of the takeoff and did not vary. He did not perceive and issues with respect to the engine. One of the FAA inspectors that responded to the accident site reported that the truck yard consisted of dirt and gravel. The portion of the yard used for the accident takeoff was rough and uneven. The takeoff distance available was about 750 feet. A postaccident examination did not reveal any anomalies consistent with a preimpact failure or malfunction. Flight control continuity was confirmed, which included the wing flap control system. The cockpit flap handle appeared to be in the retracted (up) position at the time of the examination. The flaps were also in the retracted position; however, the exact position of the wing flaps at the time of impact could not be determined.
The pilot’s failure to attain adequate airspeed during the short field takeoff, which resulted in an exceedance of the airplane’s critical angle of attack and an aerodynamic stall.
Source: NTSB Aviation Accident Database
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