Amateur-built ACRO II N86RL accident near Milford, New Jersey

Probable cause

The pilot’s lack of familiarity with the airplane’s fuel system, which resulted in a total loss of engine power due to fuel exhaustion.

NTSB analysis

The pilot of the experimental amateur-built biplane stated that he had just purchased the airplane and intended to fly it to his home airport. Prior to the flight he asked the previous owner questions about the fuel indicator tube (a sight gauge indicating the fuel quantity) and noted that it had no markings. He subsequently departed for the planned the 2 hour and 12-minute flight with fuel tank completely filled with 26 gallons of fuel and assumed an 8 gallon per hour fuel consumption rate. About 1 hour and 15 minutes into the flight, the fuel sight gauge began showing a reduced fuel level in the tank, and indicated what the pilot though was 7/8 of a tank of fuel remaining. After flying 20 more minutes the fuel gauge indicated 1/2 tank of fuel, and after 15 more minutes of flying the fuel gauge was getting close to empty. He flew another 15 minutes and was about 10 minutes from his destination airport when the engine lost all power. He immediately looked for a place to make an emergency landing. He lined up on a field and landed smoothly. During the landing rollout, tall grass wrapped around the main landing gear and the airplane nosed over, resulting in substantial damage to the biplane’s top wing and the vertical stabilizer. The pilot stated that there were no preimpact mechanical malfunctions or failures that would have precluded normal operation of the airplane and that the airplane ran out of fuel.

Text from the NTSB. Open the NTSB docket for ERA24LA225 for the full record.