CHI07LA179

The airplane impacted terrain following a loss of engine power during a maintenance test flight with a company certified flight instructor (CFI) and mechanic. Earlier on the day of the accident, the airplane experienced a loss of engine power during an instructional flight. The student pilot switched fuel tanks, engine power was regained, and the airplane landed without further incident. Subsequent maintenance inspection revealed no fuel flow when fuel was drained through the gascolator with the right fuel tank selected. The mechanic inspected the airplane and called the CFI to perform a maintenance test flight in the airport traffic pattern. No anomalies were noted during the engine runup for the maintenance test flight. The test flight was planned to be conducted in the airport traffic pattern at traffic pattern altitude. The CFI reported that on the turn to base leg, she adjusted the throttle to 1,700 rpm, and the engine started to sputter and ran rough at an engine speed of 500 rpm. The CFI reported running the engine-out checklist by memory, but it did not accomplish an engine restart. The CFI decided the best option was to land in a cornfield to avoid trees and power lines. A postaccident investigation revealed that there were no detents evident in the fuel selector and that it was difficult to turn. The fuel selector did not possess safety wire on its mounting screws. The carburetor drain valve exhibited a brown colored material consistent with rust. The carburetor float had a green line around the float and rested above its minimum level. The green line was consistent with a reaction of the bronze float with water. The accelerator pump check valve was stuck and material consistent with water corrosion was noted within the accelerator pump. The bottom portion of the carburetor bowl contained a material consistent with rust and shiny gouges consistent with recent tooling marks adjacent to the area possessing rust at the bottom of the bowl. The airplane was operated without shoulder harnesses while providing rental/flight instruction.

History of flight

On June 23, 2007, at 1353 central daylight time, a Piper PA-28-140, N1768T, operated by St. Louis Sport Aviation LLC, received substantial damage on impact with terrain during a forced landing near Columbia, Illinois. The airplane experienced a total loss of engine power during a maintenance test flight. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 flight was not operating on a flight plan. The certified flight instructor (CFI) and mechanic sustained no injuries. The local flight originated from Sackman Field Airport (H49), Columbia, Illinois, at 1330.

During a previous flight in the accident airplane, the CFI was providing flight instruction during a slow flight maneuver when the engine experienced a loss of power. The fuel selector was selected to the right fuel tank, the electric fuel pump was on, and the carburetor heat was on during the maneuver. When the throttle was advanced in order to maintain altitude, the engine speed dropped below 500 rpm. The CFI stated that when the student pilot selected the left fuel tank, the engine regained power "almost instantaneously." The CFI returned to the airport, landed without incident, and called the mechanic.

The mechanic reported that he drained and checked fuel samples from left and right fuel tanks, and gascolator. While draining the fuel tanks, fuel would not flow from the gascolator when the fuel selector was selected to the right fuel tank but would flow when selected to the left fuel tank. The fuel was drained into unmarked tanks which were later used to refuel the airplane. When the fuel tanks were empty, he noted that they were clean and had no obstructions to the tank outlet screens. The fuel selector was removed, disassembled, and found unobstructed. The fuel tanks were refilled, and the engine was operated with each tank selected. The magnetos were checked and a reduction of engine speed of 100 rpm was noted with the selection of the left magneto and a reduction of engine speed of 75 rpm was noted with the selection of the right magneto. There were no fuel leaks noted.

The CFI stated that "[The mechanic] then asked if I would be willing to come back to the airport and take the plane around the pattern a couple times with him just to monitor the plane's performance. I said I would."

The CFI reported that the engine did not seem rough during the engine runup at 2,000 rpm. Both fuel tanks were checked for engine operation and the reduction in engine speed during the magneto checks was 100 rpm. The CFI stated that the engine "seemed to be running well." The CFI stated the takeoff was performed with the left fuel tank selected. The CFI reported that on the turn to base leg, she adjusted the throttle to 1,700 rpm, and the engine started to sputter and the engine speed decreased to 500 rpm. The CFI reported running the engine out checklist by memory, but engine power was not regained. The CFI stated that she decided the best option was to land in a cornfield just beyond the gas station to avoid trees and power lines.

Personnel information

The pilot held commercial pilot and CFI certificates with airplane single-engine land and multi-engine land ratings. The pilot held a second class medical certificate and had 450 hours total time, of which 50 hours were in the make and model of the accident airplane, all which was accumulated in the past 90 days.

Aircraft information

The 1970 Piper PA-28-140, serial number 28-7125087, airplane was registered to and operated by St. Louis Sport Aviation LLC, as a rental/instructional airplane. The airplane received its last annual inspection on March 4, 2007, at a tachometer time of 4,605.55 hours.

The airplane was powered by a Lycoming O-320-E3D, serial number L-45128-27A, engine, that was overhauled along with its accessories on September 20, 2001, at a tachometer time of 4,517.37 hours. The engine received its last annual inspection on March 4, 2007, at a tachometer time of 4,605.55 hours.

The aircraft had a supplemental type certificate, number SE01943CH, which allowed the use of the following approved fuels: unleaded automotive gasoline 87 minimum antiknock index, per ASTM Specification D-439 or D-4814 of any volatility class, A through E, or 82UL AVGAS per ASTM D-6227.

The operator used a mixture of 50 percent 87 octane automotive gasoline and 50 percent 100 low lead (LL) aviation fuel. The operator would obtain the 87 octane automotive gasoline from a local gas station using plastic containers for storage. The operator stated that he would use an alcohol test kit purchased from the Experimental Aviation Association. He stated that in June 2007, the local gas station stopped selling non-alcohol 87 octane automobile gasoline and since that time he has used 100 LL. The operator stated that the airplane was refueled one or two times with 100 LL prior to the accident. The operator estimated that at the time of the accident, the accident airplane fuel tanks contained 10 percent automotive gasoline and 90 percent 100 LL.

According to a review of aircraft records by the Federal Aviation Administration, the airplane did not have a current weight and balance.

Wreckage and impact information

The airplane impacted a corn field approximately 1/2 mile from H49.

Both wing tanks contained a blue liquid consistent with 100 LL at a level that was 1/2-3/4 inch above the fuel tank tab. Fuel samples taken from the wings and gascolator did not exhibit contamination. Fuel drained from the carburetor bowl through the carburetor drain plug did not exhibit contamination, but the drain plug possessed a brown colored material consistent with rust. Air was blown through the fuel selector to wing tank fuel line with the fuel caps installed and air was expelled from each fuel tank's vent lines. There were no kinked or leaking fuel lines in the fuel system.

The cockpit mixture control lever was moved from the full aft to full forward positions and the carburetor mixture control moved simultaneously from the full lean to full rich positions. The engine top spark plugs were removed and the engine propeller was rotated by hand. Air was expelled from each top engine cylinder hole. The number one cylinder primer line was broken off.

The Global Positioning System receiver database update was not documented in the aircraft logbooks.

The Hobbs meter indicated 113.8 hours and the tachometer indicated 4,669.29 hours at the accident site.

Survival aspects

The airplane was not equipped nor was it required under aircraft certification regulations to be equipped with shoulder harnesses; however, aftermarket shoulder harness installations were available under supplemental type certificate for the make and model of accident airplane. The CFI reported minor injuries due to a cut on her chin.

Advisory Curricular AC-91-65, Use of Shoulder Harnesses in Passenger Seats, states, that 20 percent of fatally injured occupants could have survived with shoulder harness and 88 percent of the seriously injured could have had significantly less severe injuries with the use of shoulder harnesses.

Tests and research

Examination of the carburetor, left and right magnetos, fuel hoses, and fuel selector valve was conducted under the supervision of the National Transportation Safety Board. The carburetor inlet was black in appearance consistent with fire that occurred at an unknown time. The carburetor was flowed on a test stand where the accelerator pump was noted to provide a vertical stream of test fluid of approximately 3 inches, which was not consistent with a normally operating flow height of several feet. The carburetor drain valve was unscrewed and the interior tip of the valve exhibited a brown colored material consistent with rust. The carburetor float had a green line around the float and rested above its minimum leve