WISE, NC, USA
N1401P
Aerofab Inc. LAKE LA-4-250
The pilot reported that while attempting a water takeoff from Lake Gaston, in Halifax County, North Carolina, the airplane encountered a boat wake. A right turn was made to parallel the wake, resulting in dragging the right sponson, and a water loop ensued. The FAA Advisory Circular 61-21A-Flight Training Handbook discusses the forces that act on a seaplane during a crosswind takeoff. It states that the crosswind pushes the airplane sideways, acting along with the friction of the airplane on the water causing the airplane to weathervane into the wind. The turn is aggravated by the occurrence of centrifugal force. This is opposed by the water reaction on the hull and if strong enough and, in combination with the wind may cause the seaplane to tip, submerging the downwind float and causing the wing to strike the water. This is known as a 'water loop'.
On July 4, 1998, about 1100 eastern daylight time, an Aerofab, Inc. Lake LA-4-250, N1401P, dragged the right wing during a water takeoff near Wise, North Carolina. The airplane was operated by the pilot/registered owner, under the provisions of Title 14 CFR Part 91, and visual flight rules. A flight plan was not filed for the personal flight. There were no injuries to the private pilot or to his passenger, and the airplane was substantially damaged. The pilot reported that while attempting a water takeoff from Lake Gaston, in Halifax County, North Carolina, the airplane encountered a boat wake. A right turn was made to parallel the waves, resulting in dragging the right sponson, and a water loop ensued. The FAA inspector stated that the pilot's initial notification of the occurrence described minor damage. Subsequently, the mechanic repairing the airplane reported that the outboard six feet, approximately, of the right wing requires rebuilding, a major repair. The FAA Advisory Circular 61-21A-Flight Training Handbook discusses the forces that act on a seaplane during a crosswind takeoff. It states that the crosswind pushes the airplane sideways, acting along with the friction of the airplane on the water causing the airplane to weathervane into the wind. The turn is aggravated by the occurrence of centrifugal force. This is opposed by the water reaction on the hull and if strong enough and, in combination with the wind may cause the seaplane to tip, submerging the downwind float and causing the wing to strike the water. This is known as a "water loop". The FAA Investigator stated in his report that the airman will receive additional water instruction prior to any additional water operations.
The pilot's improper turn during the takeoff that resulted in dragging the sponson. A factor was the rough water caused by the boat wake.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
