Amateur-built RANS S6ES N26PP accident near St. Augustine, Florida

Probable cause

A total loss of engine power during initial climb for undetermined reasons.

NTSB analysis

The accident flight was the first flight after the experimental light sport airplane's engine was removed and replaced. During initial climb, the engine experienced a partial power loss, followed by a total loss of power. During the emergency glide back to the airport, the airplane struck utility wires just prior to the runway. The wreckage was recovered and stored outside, unattended at the airport. Several weeks later, examination of the engine revealed no mechanical discrepancies that would have prevented normal operation. Following the examination, the engine was started and ran uninterrupted.

The airplane owner stated that during engine installation, the mechanic routed the carburetor vent lines upward and tie-wrapped them at the top of each carburetor. The owner further stated that someone must have tampered with the wreckage, as the carburetor vent lines were found routed downward when the engine examination was conducted. The owner subsequently provided a blurry photograph of the engine during installation, prior to the accident, which showed the carburetor vent lines routed upward and tie-wrapped. The engine manufacturer confirmed that upward routing of the lines into an area of positive static pressure could result in fuel starvation.

The mechanic stated that it did not matter if the carburetor vent lines were routed upward or downward and he could not remember which way he routed them on the accident airplane. He further stated that the installation manual did not specify if the lines should be routed upward or downward.

Review of Rotax installation manual excerpts, provided by the mechanic, revealed:

"15) Carburetor...CAUTION: The float chamber venting lines (3) lines have to be routed in a ram-air and vacuum free zone or into the airbox, according to the requirements and release of BRP-Rotax...These lines must not be routed into the slipstream or down the firewall...15.1.1) Drainage piping on airbox and drip trays...WARNING...Route the lines with a continuous decline."

A low fuel level was found in the carburetor float bowl and the mechanical fuel pump, which was consistent with a possible fuel issue that included incorrect carburetor vent hose routing as stated by the airplane owner.

Text from the NTSB. Open the NTSB docket for ERA11LA079 for the full record.