ANC93LA101

A powerplant failure for undetermined reasons occured over terrain unsuitable for an emergency landing. The pilot ditched the airplane and it sank.

On June 23, 1993, at approximately 1605 Alaska daylight time, a wheel equipped Grumman American AASA airplane, N9765U, ditched in the Lynn Canal near Comet Mine, approximately 50 miles north of Juneau, Alaska. The flight was reportedly conducted under 14 CFR Part 91 for personal reasons, and had departed Juneau earlier on June 23 at an unknown time without a flight plan filed. Visual meteorological conditions existed. The Commercial pilot and the two passengers were not injured. The aircraft sank in shallow water and was substantially damaged.

Information received from aircraft flying in the vicinity of the ditching indicated the pilot reported a loss of engine power at 2,500 feet while on a local sightseeing flight and elected to "land in the water" because of the unsuitability of the rocky shoreline. The sectional chart of the Lynn Canal, north of Juneau to Skagway and Haines, indicates no airports along the "fiord" type waterway for a distance of approximately 50 miles. The shoreline rises in most places from sea level to over 6000 feet in a distance of less than a mile. The pilot in command had selected a route of flight and an altitude within this fiord route.

The airplane sank in shallow water and was recovered at low tide and on June 24, 1993, the airplane wreckage was transported by external-load helicopter to the road system connecting to Juneau. FAA inspectors from the FAA FSDO-S Juneau office told the NTSB that their efforts to see the airplane when it was recovered by external load helicopter were unsuccessful.

The aircraft was reported lifted from the water ditching site to the road system north of Juneau. The operator told the NTSB that he "took the airplane apart and brought it to my garage." When asked if the NTSB could review his log books and maintenance records, the operator said that "I lost all of my log books."

The pilot reported that the aircraft had 38 gallons of automobile gasoline in the airplane at takeoff from Juneau. The circumstances and events relating to the amount of fuel actually in the aircraft on departure and at the time of the power loss remain undetermined. Recent maintenance and annual inspection data could likewise not be verified, nor could the Supplementary Type Certificate (STC) for the use of automobile fuel. All records were reportedly lost at the time of the ditching, as the operator told investigators that they were aboard the aircraft in flight but not after the aircraft was salvaged.

The pilot reported that airplane's carburetor, model MA-4 SPA (Marvel Schebler) malfunctioned, caused by "capscrews holding float chamber to throttle body were working loose." He also stated that "Safety lock tabs did not hold float body to throttle plate securely." Investigators could not verify the pilot's statement due to the removal of the airplane after the accident.