ERA25LA216 · Cessna 172F

The pilot and two passengers were on a multi-leg cross-country flight under instrument flight rules. After refueling the airplane fully, they departed on the accident flight and flew to an intermediate airport where the pilot performed a practice instrument approach. After landing the airplane and departing again, they flew toward the destination airport, where the pilot planned to perform another practice instrument approach. About 1-mile from the final approach fix, and while flying over the ocean, the airplane’s engine suddenly lost power. The pilot had his passenger inform air traffic control of the emergency before ditching the airplane into the water about 5 miles offshore. All three occupants incurred minor injuries and were rescued after the accident. The airplane was not recovered and presumed substantially damaged. Review of ADS-B data for the flight revealed that the airplane had been aloft for less than 2.5 hours since last being fueled to its full capacity of 38 gallons. According to the airplane’s Pilot Operating Handbook, at cruise power settings the airplane’s estimated consumption ranged from 8.0 to 9.0 gallons per hour. Accounting for fuel consumed during taxi, takeoff, climb, and descent, the total fuel consumption for the flight was estimated to be between 20 and 23 gallons. This suggests that about 15 to 18 gallons of usable fuel remained at the time of the accident. The weather conditions reported at the destination airport included a calculated relative humidity of 40% percent. Review of the icing probability chart contained within Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were conducive to serious carburetor icing at glide power. Because the airplane was not recovered, and the wreckage could not be examined, the reason for the loss of engine power could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset