Aviation Accident Summaries

Aviation Accident Summary LAX00LA139

TONOPAH, AZ, USA

Aircraft #1

N73BP

Scovil KR-2

Analysis

During a forced landing in the median of an interstate highway, the airplane collided with trees. According to the pilot, past the halfway portion of his flight, he noticed the fuel gauge was reading too low. He decided to land at the next closest airport to troubleshoot the problem. Before he could reach the airport, the engine lost power. The pilot reported that the POSA fuel-metering device had a main fuel flow that is metered by a needle with a flat milled area along the length of it. The needle slides in and out of a tube, which changes the area through which the fuel feeds. During the mid portion of the flight, the needle rotated slowly resulting in a rich mixture. This increased the fuel consumption rate until the fuel tank was emptied. The pilot stated he inspected the POSA the day after the accident and confirmed that the needle had rotated 90 degrees from the original setting to a position where the airflow was creating a siphon effect.

Factual Information

On March 24, 2000, at 1116 hours mountain standard time, a Scovil KR-2, N73BP, collided with trees while performing a forced landing in the median of highway 10 near Tonopah, Arizona. The commercial pilot, the sole occupant, was not injured. The airplane sustained substantial damage. The personal flight was flown under the provisions of 14 CFR Part 91 when the accident occurred. The airplane had departed from Whiteman Airport near Los Angeles, California, at 0800 Pacific standard time, and was destined for Steller Airpark in Chandler, Arizona. Visual meteorological conditions prevailed at the time of the accident. A VFR flight plan was filed. According to the pilot, past the halfway portion of his flight, he noticed the fuel gauge was reading lower than it should have. He said that he had already decided to land at the next closest airport to troubleshoot the problem. The fuel-metering unit has a needle, which, according to the pilot, rotated and allowed an increase in the fuel mixture. The pilot said that he slowed his descent, reduced the throttle, and got to within 15 miles of Buckeye airport when the airplane ran out of fuel. The pilot decided to attempt a landing on the I-10 freeway. As he maneuvered and got lined up over the eastbound lane, he said he saw power lines at the last second and had to dive under to avoid hitting them. After the landing, he said he noted that the right wing of the airplane was sheared off at the fuselage, the right landing gear leg casting broke in half, and the landing gear collapsed aft into the gear up position. In the pilot operator report, the pilot stated that the airplane had a POSA fuel-metering device installed on it. The fuel-metering device has a main fuel flow, which is metered by a needle with a flat milled area along the length of it. The needle reportedly slides in and out of a tube, which changes the area that the fuel feeds through. During the mid portion of the flight, the needle rotated slowly making the mixture go rich as the flight continued. This continued to progress and dramatically increased the fuel consumption rate until the tank ran dry. The pilot stated he inspected the POSA the day after the accident and confirmed that the needle had rotated 90 degrees from the original setting to a position where the airflow was creating a siphon effect.

Probable Cause and Findings

The fuel control metering unit becoming disengaged and the inadvertent use of the fuel supply during flight.

 

Source: NTSB Aviation Accident Database

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