Small Aircraft
Flight Crew Private
Flight Crew Last 90 Days 3; Flight Crew Total 316; Flight Crew Type 3
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Flight Crew Landed in Emergency Condition
Aircraft; Procedure
After an uneventful flight we were returning to ZZZ. We were in contact with ZZZ Approach flying at 4500 ft.. About 11-12 miles out on an approximate 240 course we were cleared to start the descent. I reduced power to about 2300 RPM and started a slow descent.  At about 2200 ft.  we were handed off to Tower and told to make straight in for [Runway XX]. About 4 minutes later and 5 miles out; just as we were cleared to land [Runway XX]; we experienced a nearly total loss of power. At that time we were flying at about 1300 ft. and at 100 MPH. Without any obvious warning engine RPM fell from about 2100-2200 RPM to 1000 RPM. The power loss was quick without any unusual engine sounds. At the time engine carb heat was already pulled and boost pump was on; mixture setting was full rich. I was unable to get the engine to produce enough power to sustain altitude and performed an uneventful landing on the dry concrete river bed. There were no injuries to myself or one other passenger and the aircraft did not sustain any damages.Engine was successfully restarted on the ground about an hour and a half following the landing. Once the aircraft was moved to the airport; aircraft was started and taxied on its own power to the tied down area. Further examination of the engine and fuel systems will be performed.Preliminary examination of the engine did not reveal any problems. There was about an hour and a half reserve of fuel at the time of the incident. The current theory is that we experienced a nearly total loss of power due to accumulation of carb ice. Weather conditions at ZZZ at the time were: sky clear; visibility 10+; 22C; 37% relative humidity; wind at about 2 kts from NNW.It is possible that I pulled carb heat too late and enough ice accumulated by that point to cause the loss of RPM. Additionally I believe that I made a serious error in judgement deciding to descend this low while being relatively far away from the airport. If I were to stay at about 2500 ft. I would have been able to make the airport even after a drastic engine power loss. Additionally there would have been more time to allow carb ice to melt. As it happened; it took about 2 minutes from the onset of engine power loss to landing.
Pilot reported landing in a concrete creek bed after engine failure.