CEN13LA455

The pilot reported that the engine run-up and the initial takeoff were normal and that the airplane rotated at 50 mph and lifted off at 60 mph. The airplane then accelerated to its best angle of climb speed and cleared the front edge of a band of trees that bordered the end of the runway, after which it descended into the trees and subsequently impacted terrain. The pilot reported that he did not know exactly what happened but stated that it appeared the airplane got into a downdraft or experienced an engine power loss. He further surmised that the airplane "lost lift," which resulted in the impact with trees. An examination of the airplane after the accident showed no preimpact anomalies; however, an examination of the engine was not accomplished due to the position of the airplane at the accident scene. The weather conditions at the time of the accident included a gusting wind. The Federal Aviation Administration's Pilot's Handbook of Aeronautical Knowledge states that obstructions on the ground affect the wind flow and can be an unseen danger that can break up the wind flow and create wind gusts that change rapidly in direction and speed. It further cautions that it is especially important to be vigilant when flying in or out of airports that have large buildings or natural obstructions near the runway. Based on the available evidence, the pilot likely failed to maintain adequate airspeed in the climb, which led to the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall. It is also likely that the airplane encountered a local disturbance due to the wind and trees that exacerbated the event; however, the pilot should have anticipated this possibility and taken appropriate measures to avoid the stall.

On July 28, 2013, about 1052 eastern daylight time, a Piper PA-28-140, N286P, impacted trees and terrain during initial climb after takeoff from runway 27 at the Timber House Airport (31IN), Lafayette, Indiana. The pilot and three passengers received minor injuries. The airplane was substantially damaged. The airplane was registered to an individual and operated by a private pilot as a personal flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The local flight was originating at the time of the accident.The pilot reported that he performed a pre-takeoff run-up and noted no deficiencies. He then proceeded to take off to the west noting that rotation occurred about 50 miles per hour, and liftoff occurred about 60 miles per hour. He stated that the airplane accelerated to 74 miles per hour (best angle of climb airspeed), and the airplane cleared the trees off of the departure end of the runway. The pilot stated that the airplane then descended into the trees. He noted that he was not sure what had happened but stated that it appeared to be a downdraft or an engine power loss. He further surmised that the airplane "lost lift" which resulted in the impact with the trees. A postaccident examination of the airplane revealed that the right wing impacted a tree followed by the left wing. Both wings separated from the airplane and both fuel tanks were breached. The fuselage remained predominately intact with the propeller buried in the dirt. The fuel selector was positioned on the right tank and both fuel tank caps were secure. Due to the position of the airplane at the accident site, an examination of the engine was not performed. At 1054, the weather conditions at the Purdue University Airport, Lafayette, Indiana, about 9 nautical miles northwest of the accident site were: wind 260 degrees at 12 knots, gusting to 18 knots; 10 statute miles visibility; broken ceiling at 9,000 feet above ground level; temperature 19 degrees C; dew point 9 degrees C, and altimeter 29.96 inches of mercury. The airport where the accident occurred was a private airport that had a 3,000 foot long by 100 foot wide turf runway. The west end of the runway was bordered by band of trees about 650 feet wide in the direction of runway alignment. Federal Aviation Administration (FAA) publication FAA-H-8083-25A, "Pilot's Handbook of Aeronautical Knowledge", states: "Obstructions on the ground affect the flow of wind and can be an unseen danger. Ground topography and large buildings can break up the flow of the wind and create wind gusts that change rapidly in direction and speed. These obstructions range from manmade structures like hangars to large natural obstructions, such as mountains, bluffs, or canyons. It is especially important to be vigilant when flying in or out of airports that have large buildings or natural obstructions located near the runway. The intensity of the turbulenceassociated with ground obstructions depends on the size of the obstacle and the primary velocity of the wind. This can affect the takeoff and landing performance of any aircraft and can present a very serious hazard."