What happened
During the preflight inspection of his floatplane, the pilot visually checked the fuel tanks and estimated a remaining fuel supply of 12 to 15 gallons. The pilot departed with the intention of traveling approximately 12 nautical miles northwest to a nearby seaplane base to purchase additional fuel.
While in the initial climb at an altitude of approximately 300 to 400 feet AGL, the engine quit. The pilot subsequently executed a forced landing onto the lake surface. During the descent, the aircraft entered an area of fog; due to the reduced visibility, the pilot was unable to judge when to flare, resulting in a hard landing. The pilot was not injured.
The investigation
Investigators examined the fuel system lines and found them to be integral with no breaches. During the aircraft recovery process, personnel removing the wings reported that there was no fuel remaining in either fuel bladder.
Following the recovery of the aircraft to a nearby airport, investigators drained small amounts of residual fuel from various components: 6 ounces from the low point fuel filter, 1 ounce from the fuel line connecting the boost pump to the engine, and less than one ounce from the header tank low point drain.