On October 7, 2002, about 1350 Pacific daylight time, a Cessna140, N90168, inadvertently collided with water near Avalon, California. The pilot was operating the airplane for fish spotting operations in support of a fishing boat under the provisions of 14 CFR Part 91. The commercial pilot, the sole occupant, sustained serious injuries; the airplane sank and is considered to be destroyed. The local flight departed El Monte Airport (EMT), California, about 1100 en route to Corona Municipal Airport (AJO), Corona, California. Visual meteorological conditions prevailed, and a flight plan had not been filed. The primary wreckage is at 33 degrees 15 minutes north latitude and 118 degrees 30 minutes west longitude. The pilot submitted detailed written statements and further described the event in telephonic interviews. Several hours into the fish spotting operation, radio communication between the pilot and the fishing boat was lost. The pilot decided to set up a box like pattern over the boat hoping that he could establish visual contact with the crew of the fishing boat. Distracted by the task and experiencing fatigue after several hours of intense flying, altitude was not maintained. Suddenly the airplane was headed toward the ocean surface. He added power and pulled the yoke back in an attempt to avoid the impending collision, but there was not sufficient time, altitude, or airspeed to allow for a recovery. In later statements, the pilot indicated that prior to the accident controls were functioning smoothly, continuous, and responsive. The engine was operating normally, with no roughness, sputtering, or propeller stoppage. Having topped off both 15-gallon fuel tanks prior to departing El Monte, the airplane still had about 2 hours worth of fuel on board at the time of impact. Most of the flight had been conducted at moderate power levels, typically between 1500 and 1900 rpm, which was not unusual for the airplane or the type of operations that were being conducted. Carburetor heat was used whenever a descent initiated or there were indications that ice might be present, but neither he nor anyone else that he knew of had ever experienced any such problems in that particular airplane. On the final pass, the airplane was at an altitude of about 50 feet and flying at an airspeed of approximately 60 miles per hour. After realizing that the airplane was headed for the water, the pilot's usual recovery procedure was utilized, first adding power and then pulling back on the yoke. He stated that due to the low altitude, and combined with the stressfulness of the situation, he did not have time to troubleshoot the engine or send out a distress call. In addition, he maintains that the engine did not seem to respond after full power was added shortly before the collision.