Daily Air flight 7511, a DHC-6-400 airplane, took off at 16:10 local time from Tatung Airport for a scheduled passenger flight to Orchid Island Airport. The flight was cleared for approach and landing on runway 13. In the final approach and landing phase moderate wind shear and moderate turbulence were encountered. The left crosswind and the tail wind encountered did not exceed the limits of the aircraft. After touchdown the aircraft veered off the left side of the runway and hit a barrier on one side of the runway nose-first, damaging its nose, left engine and wing. Findings related to probable causes: 1. The occurrence aircraft performed the final approach in left crosswind and landed with its nose yawing to the left. It was probably affected by the clockwise horizontal wind shear on the runway and pilot’s operation, the aircraft began drifting to the left after touching down. 2. As the aircraft was drifting to the left, the Captain had used right rudder to correct the deviation, and also pulled the power levers into the reverse range. According to the recorded engine data of torque and (reverse) power of both engines, it revealed that the Captain inadvertently pulled back the left power lever while he was intending to apply the right-turning differential power to assist him in correcting the left drift. It resulted in increasing the left reverse power and intensified the aircraft’s left drifting tendency. 3. Though the Captain attempted to get the directional control of aircraft by increasing the right rudder input and the right wheel brake pressure, however he still kept increasing the reverse power of left engine to the maximum, not knowing that he was taking the wrong side. Consequently, the aircraft veered off the runway, hit the fence and caused aircraft substantial damage.