N/A Airport
Aircraft Accident/Incident Report

Hesperia, California 92345
Monday, July 8, 2013 23:20 PDT

The pilot reported that, shortly after leveling the airplane for cruise during the night flight, he adjusted the fuel mixture control, and the engine lost all power. He performed troubleshooting procedures and discovered that by cycling the throttle forward and aft the engine would produce intermittent bursts of partial power. He subsequently landed the airplane on a road short of a runway and then the airplane slid along the shoulder and down an embankment, which resulted in substantial damage to both wings and the lower cabin structure.Postaccident examination revealed that the outer sheath of the fuel mixture control cable had become detached from its clamp on the carburetor body and that the cable’s sheath exhibited signatures consistent with movement. As a result, movement of the mixture control within the cabin resulted in unpredictable movement of the mixture control arm. When the pilot adjusted the mixture just before the loss of engine power, the detached cable likely allowed the mixture to become excessively lean. According to maintenance records, maintenance personnel tightened the clamp during the last annual inspection; however, it could not be determined if maintenance personnel improperly tightened the clamp during the inspection. No other mechanical anomalies were noted that would have precluded normal operation. Data extracted from the airplane’s engine monitor indicated that the pilot’s continued throttle control movements following the power loss would have activated the carburetor’s accelerator pump, which resulted in sufficient quantities of fuel being delivered to the engine to produce partial power.

The loss of engine power during cruise flight due to the detachment of the mixture control cable from its mounting clamp.