NTSB Identification: SEA02LA071.
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Accident occurred Sunday, April 21, 2002 in Orofino, ID
Probable Cause Approval Date: 10/24/2002
Aircraft: Brunger Osprey II, registration: N56GB
Injuries: 1 Uninjured.

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

After performing on-ground test runs of the recently purchased experimental amphibious aircraft, the pilot took off in order to perform maneuvers that would help him become familiar with the feel and performance of the airplane. After performing maneuvers for about 55 minutes, the pilot established the aircraft on a five-mile straight-in final approach for a full-stop landing. As he reduced the power below 2,000 rpm, he applied full carburetor heat. About one mile from the end of the runway, the engine started to run rough and then quit. During the attempted forced landing, the pilot, who does not hold a seaplane rating, flared too high, and while he was attempting to correct for the misjudged height, one of the aircraft's wings impacted the water and sustained substantial damage. A post-accident inspection of the engine revealed that the carburetor heat warm air collection shroud was approximately half the size of the equivalent shroud used on Lycoming O-320 series engines mounted on certified aircraft. In addition is was discovered that the carburetor heat box butterfly valve fit loosely and did not have sealing material on its edge. The inspection also revealed that a number of coils of the support wire inside that scat tubing that directs hot air to the carburetor throat had collapsed. Using the FAA/DOT Carburetor Icing Probability Chart, it was determined that at the time of the accident, the aircraft was operating in ambient conditions that were conducive to moderate icing at cruise power and serious icing a glide power.

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

The aircraft's inadequate carburetor heat air box system, leading to an accumulation of ice in the carburetor throat during final approach to landing. Factors include carburetor icing conditions, the pilot's failure to correctly judge the height of the aircraft above the landing surface, and the pilot's total lack of experience in executing water landings.

Full narrative available

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