Flight Design CTLS N505MA accident near Encino, New Mexico

Probable cause

A partial loss of engine power due to fuel starvation, which likely resulted from a leak in the fuel system.

NTSB analysis

During the preflight inspection, the pilot conducted a visual fuel level check through the sight gauges in each wing. He determined that right wing had 7 gallons of fuel and the left wing had 6 gallons of fuel which he deemed was enough for a one-hour local flight. About 35 minutes after take-off, the engine started to "surge". The pilot manipulated the throttle lever several times, but there were no corresponding responses from the engine. The pilot elected to land on a nearby road; however, as he turned from base to final for the road, the engine "surged to life." The landing gear contacted the grass, and the airplane subsequently came to rest inverted.

A postaccident examination of the airplane revealed an unmeasured amount of fuel in the right wing, and the left wing appeared to be empty. The gascolator drain valve was opened and no liquid was drained. Because the gascolator was located at the lowest point in the fuel system and contained no fluid, it is likely the engine was starved of fuel. An accumulation of dirt was noted on the fuselage lower belly skin (in the vicinity where a fuel drain tube exits the engine compartment), which was consistent with evidence of a previous fuel leak. Additionally, the area around the engine-driven fuel pump also exhibited evidence of a previous leak. The location of the potential leak could not be determined based on available information.

Text from the NTSB. Open the NTSB docket for WPR20LA098 for the full record.