On March 23, 2014, about 1400 eastern daylight time, a Cessna O-1A, N211PP, operated by Advertising Airforce, was substantially damaged when it collided with water during a forced landing following a total loss of engine power during climb-out from Albert Whitted Airport (SPG), St. Petersburg, Florida. The commercial pilot was not injured. Visual meteorological conditions (VMC) prevailed, and no flight plan was filed for the banner-tow flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.According to the operator, the pilot had completed a two-hour flight and subsequently serviced the airplane with 16.5 gallons fuel. He then completed a second banner tow flight, which was one hour in duration, before picking up a third banner. The pilot's first pick-up attempt was unsuccessful. He circled the pick-up location for a brief period, and completed the pick-up on the second attempt. During the initial climb, about 300 feet, the engine experienced a total loss of power. The pilot released the banner and completed a forced landing to Tampa Bay. The pilot reported that the entire flight was conducted on the left main fuel tank. The pilot held a commercial pilot certificate with ratings for airplane multiengine land, single engine land and instrument airplane. He also held a flight instructor certificate with a rating for airplane single engine. His most recent Federal Aviation Administration (FAA) second class medical certificate was issued on May 31, 2013. He reported 3,070 total hours of flight experience, of which 2,863 hours were in single-engine airplanes. At the time of the accident, the weather reported at SPG included winds from 260 at 12 knots. The temperature was 25 degrees C, and the dew point was 19 degrees C. According to FAA and maintenance records, the airplane was manufactured in 1951. Its most recent 100-hour inspection was completed February 27, 2013, at 10,140 aircraft hours. The airplane was powered by a 213 horsepower, Continental O-470-11, six-cylinder, horizontally opposed, air-cooled engine with a pressure carburetor. The airplane was equipped with four fuel tanks; with one main tank and one auxiliary tank in each wing. Each main tank had a capacity of 20.5 gallons, of which 18 gallons were usable. Each auxiliary tank had a capacity of 12 gallons, of which 11.5 gallons were usable. The airplane was recovered from the water and examined by an FAA inspector. Examination and then draining of the fuel tanks revealed that the right main and auxiliary tanks were full and contained "some" sea water. The left auxiliary tank was full and contained some sea water, and the 18-gallon left main tank was empty, dry, and contained no traces of fuel or water. The fuel selector was found in the right main tank position, and the fuel boost pump was in the off position. When interviewed, the pilot stated he did not remember switching the fuel selector to the right tank, and thought the selector remained in the left tank position. The engine was flushed with water and diesel fuel to preserve it, and slave magnetos were mounted. The airplane was serviced with fuel, a new battery was installed, and an engine start was attempted. The engine started immediately, and ran continuously without interruption. ADDITIONAL INFORMATION Interpolation of a fuel consumption chart located in the manufacturer's operating handbook indicated that, in cruise flight, on a standard day (15 degrees C, sea level), the airplane would consume approximately 7 gallons per hour at 2,000 rpm, and 10 gallons per hour at 2,300 rpm. These numbers assume a clean configuration (wing flaps retracted), with no banner in tow. According to a representative of the engine manufacturer, the airplane's engine was a military variant of the O-470, which could consume as many as 21 gallons per hour in a full-power climb. According to the operator's copy of the Pilot Operating Handbook (POH) in use at the time of the accident, item 6 of the DESCENT checklist: "Fuel selector valve handle – Fullest tank." The operator's training syllabus stated, "While flying, periodically check your fuel supply, oil pressure and temperature, magnetos, and carburetor heat."