SEA04LA064

Not long into the flight the left engine began running rough. After adjusting the engine controls the engine smoothed out, but then began running rough again, prompting the pilot to proceed to his home base. Approaching his destination and observing that he could only get 1900 rpm out of the right propeller after advancing the throttle to 28.5 inches of manifold pressure, the pilot elected to proceed to a nearby airport. However, due to a radio communication failure and inability to maintain sufficient altitude to clear terrain bordering the airport, the pilot decided to make a water landing on the 20 square-mile bay adjoining the airport. Not realizing the tide was out and that the water was only about 6 inches deep, the pilot landed approximately 600 to 650 feet paralled to the shoreline. Subsequently, the right wing float impacted subsurface terrain, collapsing the float aft in compression and pivoting the float aft and up, substantially damaging the right aileron and four wing ribs. A post accident examination of the right engine and propeller revealed the propeller's oil control valve had developed a leak, which resulted in a lack of engine oil to the propeller. No definitive reason for the leak had been determined. Examination of the rough running left engine failed to reveal any anomalies which would preclude normal operation.

On April 2, 2004, approximately 1230 Pacific standard time, an amphibian Grumman G-44 multiengine airplane, N65914, sustained substantial damage after impacting terrain while making a water landing near Bellingham, Washington. The aircraft was registered to and operated by a private individual. The commercial pilot and his two passengers were not injured. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 CFR Part 91 personal flight. The flight originated from Lake Whatcom, Washington, at approximately 1210.

According to the Pilot/Operator Aircraft Accident Report (NTSB form 6120.1/2), and in a telephone interview with the NTSB investigator-in-charge (IIC), the pilot reported that not long into the flight the left engine developed intermittent roughness, which smoothed out after the pilot reduced his power setting. The pilot reported that he then decided to proceed to his home base. The pilot stated that while approaching his home base he advanced the right propeller control to full increase and opened the right throttle to 28.5 inches of manifold pressure, but could only get 1900 rpm out of the right propeller. The pilot reported that at 1,200 feet above ground level and in a slow descent his intention was to land at Bellingham International Airport (BLI). The pilot related that due to a communications failure and unable to clear terrain bordering the airport, he opted to make a water landing in Bellingham Bay, a bay which encompasses an area of more then 20 square miles. The pilot reported, "The only thing I didn't realize before landing was that the tide was out." The pilot stated it was only after he landed in the bay, 600 to 650 feet parallel to the shoreline, that he realized the water was only about 6 inches deep. The pilot stated that the right wing float impacted subsurface terrain, collapsing the float aft in compression and pivoting the float aft and up, substantially damaging the right aileron and four wing ribs.

On May 13, 2004, the IIC spoke with the pilot, who is also the registered owner and an FAA certificated airframe and power plant mechanic. The pilot reported that during the examination of the right engine, the engine's propeller control valve had developed a leak which resulted in a lack of engine oil to the propeller. The pilot stated that no definitive reason for the leak had been determined. The pilot also reported that as a result of his examination of the left engine, which he had reported as "running rough" during the flight, he found no anomalies with the engine which would preclude normal operation.