Aviation Accident Summaries

Aviation Accident Summary SEA99LA066

BURLINGTON, WA, USA

Aircraft #1

N6700N

Mooney M-20G

Analysis

The pilot attempted a forced landing after a loss of engine power. While attempting to restart the engine, he overshot the road he had selected for his forced landing, turned, retracted the landing gear, and 'waited for the impact.' After the wreckage was recovered, FAA inspectors ran the engine to 1600 rpm. They also removed the main fuel screen, and found it full of a 'gel-like' substance. The carburetor finger screen had captured some foreign matter, but was not judged to have been blocked. Upon disassembly of the carburetor, foreign material was found blocking the main metering jet orifice, along with some large particles, with a surface area similar to that of a small thumbtack. It could not be determined how those particles bypassed the finger screen. The airplane had been recently painted and then an annual inspection had been performed. The main fuel screen and the safety wire on the main fuel screen were covered with overspray. Fresh safety wire on the carburetor float bowl was consistent with the carburetor float bowl having been drained.

Factual Information

On May 18, 1999, at 1719 Pacific daylight time, a Mooney M-20G, N6700N, sustained substantial damage during a forced landing near Burlington, Washington, after a loss of engine power. The private pilot, the sole occupant, was uninjured. No flight plan was filed for the flight. Visual meteorological conditions prevailed at the time of the accident. There was no fire. The ELT activated and was turned off by the pilot. The pilot had departed Skagit Regional airport (Burlington) about an hour before the accident. While performing maneuvers at about 2600-3000 feet, "the engine fluttered and produced minimal power. I tried the boost pump, full mixture, and pumping the throttle, but to no avail. I was three miles from the airport when I spotted a road with no power lines or obstructions. The airport was on a hill surrounded by trees. I decided the airport was too much of a risk, so I opted for the road. I circled the road, observed three mail boxes as the only obstacles that would damage the airplane. I crabbed into position over the road. Attempted to start the engine one last chance. It sputtered. I tried again, it sputtered and quit. By this time I had been dragged down the road too far to make a safe landing so I turned off the road, pulled up the landing gear and waited for the impact. The left wing hit the ground first which spun the aircraft to the left and slammed into the ground and slid backwards to a full stop." During the course of investigation after the wreckage was recovered, FAA inspectors ran the engine to 1600 rpm. They also removed the main fuel screen, and found it full of a "gel-like" substance. The carburetor finger screen had captured some foreign matter, but was not judged to have been blocked. Upon disassembly of the carburetor, foreign material was found blocking the main metering jet orifice, along with some large particles, with a surface area similar to that of a small thumbtack. It could not be determined how those particles bypassed the finger screen. No other anomalies of the fuel system or powerplant were noted. The airplane had been recently painted and then an annual inspection had been performed. The main fuel screen and the safety wire on the main fuel screen were covered with overspray. Fresh safety wire on the carburetor float bowl was consistent with the carburetor float bowl having been drained.

Probable Cause and Findings

A loss of engine power due to carburetor contamination. Factors include the pilot's misjudgment of altitude and distance when he performed his forced landing.

 

Source: NTSB Aviation Accident Database

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