Amateur-built VANS RV9A accident near Kingston, Oklahoma, January 28, 2015

The NTSB's narrative final · quoted from the NTSB record

The student pilot contacted a friend who was in a fishing boat and told him he was going to fly over the lake. The friend then saw the airplane circle over his fishing boat, which was a prearranged signal by the student pilot to notify the friend to drive his fishing boat towards a better fishing spot. The airplane was flying in a descending left turn and impacted the water and sank. The airplane was located the following day and was recovered to the shore. Although damage was sustained during the recovery phase, an examination of the airframe did not find any preimpact anomalies. The circumstances of the accident are consistent with an accelerated stall while the airplane maneuvering at low altitude. An examination of the engine found that continuity to the engine controls was established with the exception of the carburetor heat gate cable. An examination of the carburetor heat gate cable did not find any deformation consistent with the set screw being installed properly at the time of the impact. A family member reported that the pilot previously had the carburetor heat repaired, but no logbook entry could be found to tell when and by whom the carburetor heat was repaired. A review of the carburetor icing probability chart found that, at the time of the accident, the airplane operated in an area with the potential for serious icing at glide power. During the circling maneuver, it is likely that the pilot was operating the airplane a reduced power setting, which resulted in the formation of carburetor icing and led to a loss of engine power. However, once power was lost, the pilot continued in a bank turn, which resulted in the accelerated stall, rather than maintaining level flight.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.