Narrative:

Upon coordination with approach control; I was cleared to land on runway xx. At that time I had begun my descent from 3;500 ft MSL. I immediately noticed the change in the noise output of the engine; which raised an alarm. I checked my oil pressure; and engine temperature gauges; which verified my suspicion of an engine failure. I determined that I only had enough time to do a flow check; as to troubleshoot why the engine was not working. After concluding there was nothing I could do to get full power restored; I notified approach I was diverting. I quickly calculated I didn't have enough potential energy to glide across the water. I then notified approach I was going to land on the highway to my left (I was southwest bound). That was the last radio communications I had with approach. I was able to use a phone to call a weather briefer; who then called tower; to notify them I was on the ground; and no person or equipment was harmed.

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Original NASA ASRS Text

Title: C150 pilot reported a significant loss of power during descent for landing. After determining that power could not be restored and that the airport was beyond gliding range; an off airport landing was accomplished.

Narrative: Upon coordination with Approach Control; I was cleared to land on runway XX. At that time I had begun my descent from 3;500 ft MSL. I immediately noticed the change in the noise output of the engine; which raised an alarm. I checked my oil pressure; and engine temperature gauges; which verified my suspicion of an engine failure. I determined that I only had enough time to do a flow check; as to troubleshoot why the engine was not working. After concluding there was nothing I could do to get full power restored; I notified Approach I was diverting. I quickly calculated I didn't have enough potential energy to glide across the water. I then notified Approach I was going to land on the highway to my left (I was southwest bound). That was the last radio communications I had with Approach. I was able to use a phone to call a weather briefer; who then called Tower; to notify them I was on the ground; and no person or equipment was harmed.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.