History of Flight
On May 26, 2012, at about 1530 Pacific daylight time, a Cessna 150F, N7093F, operated by Aerial Advertising LLC, landed in the waters of San Diego Bay, San Diego, California, after a loss of engine power. The airplane was conducting a banner tow flight under Title 14 Code of Federal Regulations Part 91. The commercial pilot and a private pilot rated passenger were not injured. The airplane sustained substantial damage. The flight departed Gillesfield Airport, San Diego/El Cajon, about 1430. Visual meteorological conditions prevailed, and no flight plan had been filed.
The commercial pilot and the passenger, who was seated in the right seat and taking photographs, performed several laps over the central bay area near the Coronado Bridge at an altitude of 500 feet above ground level. The pilot then allowed the passenger to manipulate the flight controls, and they repositioned northeast for four more laps over the bay. After completing those laps, the commercial pilot verified normal engine instrument indications and contacted air traffic control for clearance through San Diego International Airport's Class B airspace. The passenger initiated a climbing right turn towards the northwest while applying full forward throttle. The passenger reported that the instrument panel vibrated, the engine did not respond, and power was lost.
The airplane descended immediately. The commercial pilot took control, released the banner, and prepared for a forced landing in the water. Both occupants reported no time for troubleshooting due to low altitude.
The airplane struck the water, separating the right main landing gear and causing substantial damage to the forward fuselage and firewall. The airplane began to sink as the occupants egressed.
Aircraft Information
The 1966 high-wing, single-engine, two-seat airplane had been modified for banner towing. Records showed a Lycoming O-360-A4A engine installed in December 1990 under supplemental type certificate (STC) SA4795SW. Additional modifications included a short takeoff and landing kit (STC SA944CE), long-range fuel tanks (STC SA5733SW), and a modified fuel supply system with a Cessna 172 fuel selector valve located on the seat support bulkhead under the passenger seat lip. A "Gassor Tow Hitch" assembly was installed in May 1990. The long-range fuel tanks had a total capacity of 42 gallons, with fuel venting through an interconnecting hose and a vent tube on the left tank.
Maintenance records indicated an annual inspection on June 23, 2011, at a total airframe time of 6,844.38 hours. The engine had accrued 892.7 hours since overhaul in July 2001. Based on tachometer time on the morning of the accident flight, engine and airframe had accumulated about 28 flight hours since the annual inspection.
Meteorological Information
An automated surface weather observation at San Diego International Airport, about 1.5 miles northwest of the accident site, issued at 1551 indicated wind from 280 degrees at 10 knots, 10 miles visibility, few clouds at 3,200 feet, temperature 18°C, dew point 7°C, and an altimeter setting of 30.06 inches of mercury.
Tests and Research
The airplane was recovered from the sea bed the following day. Recovery personnel reported the right tank contained fuel and water, with about 10 gallons of fuel recovered; the left tank had no fuel. The fuel selector valve was found set to the right tank position. The throttle, fuel mixture, and carburetor heat controls were all forward, and flaps appeared set to about 5 degrees of extension.
The pilot stated that standard operating procedure was to leave the fuel selector in the both position during run-up and banner towing. He confirmed the selector was in both during preflight, and both occupants stated it had not been changed during flight. The pilot reported carburetor heat was not used when the engine lost power because it had been operating at 2,100 to 2,300 rpm. He stated both fuel tanks were full at departure.
Engine examination revealed minimal damage. All controls were continuous. A blue-colored liquid consistent with aviation gasoline was present in the gascolator and supply lines, with residual blue fluid and water in the hose between the engine-driven fuel pump and carburetor. The inlet air filter and induction lines were unobstructed. Top spark plugs showed normal wear signatures. The crankshaft turned freely, cylinder compression was noted on all cylinders, mechanical continuity was established, and an audible click from magnetos was heard. Saltwater corrosion prevented accurate magneto testing. Combustion chambers showed no foreign object damage and light grey deposits consistent with normal operation.
No anomalies with the airframe or engine were found that would have precluded normal operation. The carburetor icing probability chart from FAA Special Airworthiness Information Bulletin CE-09-35 showed a probability of serious icing at glide power given the temperature and dew point at the accident time.
The carburetor and engine-driven fuel pump were examined with no anomalies noted.