NTSB Identification: CHI04LA253.
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Accident occurred Friday, September 10, 2004 in Hayward, WI
Probable Cause Approval Date: 07/07/2005
Aircraft: Williams Glastar GS-1, registration: N501YR
Injuries: 2 Serious.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The float equipped airplane collided with trees following a loss of control while taking off from a lake. The pilot reported that prior to takeoff he added one notch of flaps, raised the water rudders, and let the airplane weather vane into the wind. He reported that during the takeoff the airplane "... buffeted as if the wind direction was changing rapidly." The pilot reported he was over the trees at the end of the lake at an airspeed of 60 miles per hour (mph) and an altitude of 150 feet above ground level (agl), when the airspeed went to zero and the right wing dropped. He reported that he corrected by applying aileron, but the airplane rolled to the left. He reported the airplane leveled out at an altitude of about 100 feet agl prior to experiencing a "... total loss of lift... ." The pilot stated he attempted to get the airplane as close to shore as possible. The airplane came to rest on a beach with the right wing in the water. The pilot reported during an interview, that he used two notches of flaps for takeoff and he applied full flaps when he was having difficulty gaining altitude. The pilot reported "Wind shear on takeoff, the magnitude of which I experienced that day is hard to predict... ." The winds reported approximately 10 miles from the accident site about 22 minutes prior to the accident were from 170 degrees at 14 knots, gusting to 18 knots.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's failure to adequately compensate for the wind conditions which resulted in a loss of aircraft control. A factor associated with the accident was the gusty wind condition.

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