What happened
While on approach to Runway 36, the pilot of a single-engine airplane experienced a loss of engine power. The pilot initiated a descent at 400 feet per minute, reduced manifold pressure to 23 inches, and switched the fuel selector from the left tank to the right tank. Approximately four miles west of the destination, the aircraft entered a tight right downwind pattern at an altitude of 1,800 feet.
As the aircraft was abeam the runway numbers, the airspeed exceeded the landing gear extension speed by 10 knots, prompting the pilot to reduce manifold pressure to 18 inches. The pilot activated the fuel boost pump and moved the mixture and propeller controls forward, extending the downwind leg to decrease speed. During the turn from base, the pilot extended the landing gear and advanced the throttle, but the engine failed to respond. Unable to maintain altitude, the pilot reduced airspeed to 80 knots and performed a forced landing on a feeder road adjacent to Interstate 35. Before touchdown, the pilot confirmed the fuel boost pump was on, the fuel selector was in the detent, and the master and ignition switches were active. The flaps remained retracted during the event.
The investigation
An examination of the engine, which had been test-run with a two-bladed propeller using a provisional fuel line from a plastic gas can, showed that it started and operated normally from idle to 1,500 RPM. During the test, no mixture rise was observed when leaning the mixture at 1,500 RPM. A magneto check at 1,500 RPM demonstrated smooth operation, with RPM dropping approximately 100-125 RPM on both the left and right magneto positions.
While the cockpit fuel pressure gauge appeared sluggish and indicated slightly low pressure, a test gauge installation showed 20 psi at idle with the boost pump off and 22 psi with the boost pump on. At 1,500 RPM, the test gauge indicated 25 psi regardless of the boost pump status. The fuel vents were found to be free of debris, and the induction air filter and induction system appeared normal and unobstructed. No mechanical anomalies were identified that would have prevented normal engine operation.