Aviation Accident Summaries

Aviation Accident Summary MIA01LA059

Parkton, NC, USA

Aircraft #1

N5883B

Cessna 182A

Analysis

The flight departed with approximately 20 gallons of fuel in each fuel tank and offloaded skydivers at 10,500 feet, then descended to return with the throttle at idle, the fuel/air ratio leaned; and carburetor heat applied. At 2,000 feet, the pilot began to level off and, "realized I was having engine trouble and began my emergency procedures for an engine failure at altitude...." He checked the position of the fuel selector valve which was in the same position it was selected for takeoff, "both on." He positioned the fuel selector to the left, right, and both positions with negative results, and also checked "my ignition and check all fuses." He was unable to start the engine and performed a forced landing in a field. Before touchdown he turned off the fuel selector valve; after touchdown, the airplane nosed over. The fuel strainer was empty when examined by a mechanic approximately 45 minutes after the accident. Examination of the airplane by an FAA inspector approximately 24 hours after the accident revealed the flexible hose from the fuel strainer to the carburetor contained a slight amount of fuel (capful). No discrepancies with the fuel strainer, ignition, or vent systems noted. Following release by the FAA for recovery, the carburetor was removed and no fuel spray noted from the accelerator pump discharge nozzle when the throttle was activated. The fuel flow rate through the fuel selector valve was less with the fuel selector valve positioned to the right tank than with the valve positioned to the left or both positions. Disassembly of the fuel selector valve revealed no evidence of debris or wear; no determination was made as to the reason for the low fuel flow rate with the fuel selector positioned to the "right" position. Historical uneven fuel consumption greater from the left tank was noted while operating the airplane in skydiving operations that involve mainly climbs and descents. After repairs, the engine was placed on the airframe and operated with no discrepancies noted. Post accident testing with an exemplar carburetor, the accident fuel strainer and flexible hose from the fuel strainer to the carburetor with the assembly placed inverted revealed the carburetor leaks fluid to a certain level but fluid remains in the bowl. Additionally, with the assembly inverted and the carburetor bowl empty but fluid in the fuel strainer and flexible line, fluid does not flow into the carburetor bowl. The fuel selector valve was repaired last on March 18, 1977, in which an o-ring on the fuel selector shaft was replaced.

Factual Information

On January 7, 2001, about 1340 eastern standard time, a Cessna 182A, N5883B, registered to a private individual, operated by Airanch Skydivers, nosed over during a forced landing in a field near Parkton, North Carolina. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 skydiving flight. The airplane was substantially damaged and the commercial-rated pilot, the sole occupant, was not injured. The flight originated about 1320, from the Southern Comforts Aerodrome, near Parkton, North Carolina. The pilot stated that the flight departed with approximately 20 gallons of fuel in each fuel tank and the fuel selector valve positioned to the "both" position. The flight climbed to 10,500 feet where the skydivers were offloaded. He then began a descent to return to the departure airstrip with the throttle at idle, the fuel/air ratio leaned, and carburetor heat applied. At 2,000 feet he began to level off and "realized I was having engine trouble and began my emergency procedures for an engine failure at altitude...." The checks included checking the fuel selector valve which had not been moved by him since takeoff and was observed in the "both" position when first examined. He positioned the fuel selector to the left, right, and both positions with negative results, and also checked "my ignition and check all fuses." Unable to start the engine, he maneuvered the airplane for a forced landing in a farmer's field. When he was committed for landing, he turned off the fuel selector valve and the master switch. After touchdown in the field, the airplane nosed over. According to the airplane owner who examined the airplane at the accident site, the airplane came to rest inverted (see photograph 1), approximately 117 feet from the first point of touchdown by the left main landing gear on down sloping terrain; the flaps were not extended. An airframe and powerplant mechanic with inspection authorization who was on scene approximately 45 minutes after the accident reported no fuel in the fuel strainer when he arrived; there was no evidence of fuel leaking or any fuel stains around the firewall or at the carburetor. A copy of his statement is an attachment to this report. Examination of the airplane in the field by an FAA inspector approximately 24 hours after the accident revealed that the fuel strainer was empty; a slight amount of fuel (less than a capful) was found in the fuel line from the fuel strainer to the carburetor (see photograph 2 for view of fuel strainer). The fuel selector valve was found in the "both off" position, and examination of the ignition system revealed no discrepancies. After release of the airplane for recovery, the carburetor was removed and found to be empty; activation of the throttle did not result in fuel being discharged from the accelerator pump discharge nozzle. The airplane was recovered and placed in an upright attitude for further examination. Examination of the airplane by the FAA inspector 9 days after the accident revealed that the engine had been removed from the airframe; the fuel line from the fuel strainer to the carburetor remained secured to the fuel strainer. The fuel strainer which has inlet and outlet fittings at the top of the unit was noted to be approximately 75 percent full of fuel; no contamination was noted in either fuel tank. No obstructions were noted in the vent line (crossover line) between the left and right fuel tanks. Reduced fuel flow was noted through the fuel selector valve when positioned on the right tank position. Disassembly of the fuel selector valve revealed no evidence of debris or wear; no determination was made as to the reason for the low fuel flow rate with the fuel selector positioned to the "right" position, (see photographs 3 and 4 for views of the fuel selector). Disassembly of the fuel strainer revealed no debris. A copy of the statement from the FAA inspector is an attachment to this report. The impact-damaged engine mount and induction system were repaired; the engine was reinstalled on the airframe for a test run which was witnessed by the FAA on an unknown date. With the engine installed, fuel was added to each fuel tank and fuel leakage was noted from the top of the fuel strainer. The seals at the top and bottom of the fuel strainer were replaced with hand made gaskets from cork material. The engine was started and operated at 1,800 rpm for 2 minutes each with the fuel selector positioned to the "left", "right" and "both on" positions; no discrepancies were noted. The engine quit 23 seconds and 1 minute 37 seconds after the fuel selector was placed to the "both off" position with the engine operating at 1,800 and 800 rpm, respectively. The engine was operated at 800 rpm for 5 minutes each with the fuel selector positioned to the "left", "right", and "both on" positions; no discrepancies were noted. The last engine run consisted of operating the engine intentionally for 5 minutes at 800 rpm with the fuel selector positioned between the "left" and "right" positions; no sputtering or discrepancies were noted. A record of conversation with the FAA inspector who witnessed the engine run and a copy of the statement from the airplane owner describing the repairs and the engine run result are attachments to this report. Additionally, historical uneven fuel consumption greater from the left tank was noted while operating the airplane in skydiving operations that involve mainly climbs and descents. One pilot reportedly operated the airplane with the fuel selector positioned to the right tank position, no discrepancies were noted. Postaccident testing was performed with the accident fuel strainer, exemplar carburetor of the same model as the accident carburetor, and accident flexible hose from the fuel strainer to the carburetor. The primer and the inlet fittings which by design are at the top of the fuel strainer, were capped off before the test. The carburetor, fuel strainer, and flexible hose were connected and filled with test bench fluid and placed inverted as an assembly (see photograph 5); the fuel strainer was positioned slightly higher than the carburetor duplicating the conditions post accident. Dripping from the mixture control shaft was noted from the exemplar carburetor. The testing continued for a 24-hour period after which, the fuel strainer and flexible fuel line remained full of fuel; the carburetor bowl was found to contain 105 ml of test bench fluid. The carburetor bowl of a carburetor with a properly adjusted float holds approximately 170 ml of fluid. Additional testing was performed with the carburetor bowl empty and the fuel strainer and flexible hose full of test bench fluid. The assembly was again placed inverted with the fuel strainer slightly higher than the carburetor. The test indicated that fluid did not enter the carburetor bowl; the fuel strainer and the flexible hose remained full of fuel. The flexible hose was found to hold approximately 35 ml of fluid. The fuel selector valve was repaired last on March 18, 1977, in which an O-ring on the fuel selector shaft was replaced. A copy of the maintenance record entry is an attachment to this report. The airplane minus the retained fuel strainer and flexible hose from the fuel strainer to the carburetor was released to Mr. Ralph Rigby, the airplane owner, on June 3, 2001. The retained components were also released to the airplane owner on June 7, 2001.

Probable Cause and Findings

The loss of engine power during a normal descent due to fuel starvation for undetermined reasons.

 

Source: NTSB Aviation Accident Database

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