Aviation Accident Summaries

Aviation Accident Summary CHI97LA003

SILVER LAKE, IN, USA

Aircraft #1

N5749H

Piper PA-16

Analysis

The aircraft was topped off at Ames, Iowa, prior to the last leg of the flight. The lineman reported that he opened the left fuel cap and observed that the left tank was full. He replaced the cap and refueled the right fuel tank. The pilot reported he did not visually check the fuel level, but relied on visually checking the fuel caps from behind the wing. The aircraft burned an average of 7.5 gph fuel. The aircraft had 4.5 to 4.8 hours of fuel on board. The flight lasted about 3.7 hours. Witnesses reported the aircraft circling at about 300 feet AGL and the engine sputtering before it quit. The left wing hit a tree before the aircraft impacted the ground. The aircraft skidded up on its nose with the tail nearly vertical. The examination of the aircraft revealed that a fuel stain initiating from the left fuel cap and streaming towards the rear of the wing was clearly visible. The engine and flight controls exhibited continuity. There were open fields near the crash site. The pilot reported that the fuel gauges were unreliable.

Factual Information

On October 5, 1996, at 1310 eastern daylight time (All times in EDT), a Piper PA-16, N5749H, was destroyed when the engine lost power and hit a tree when the pilot attempted to land on a city street. The pilot had been circling a relative's home at about 300 feet when the engine quit and the pilot made an emergency landing. The private pilot and passenger received serious injuries. The 14 CFR Part 91 flight had departed Ames, Iowa, en route to Warsaw, Indiana. Visual meteorological conditions prevailed and no flight plan had been filed. The pilot reported that he and his wife departed Idaho Falls on Friday, October 4, 1996. The pilot's wife maintained the flight log during the trip, entering information such as waypoints, times, switching fuel tanks, etc. The first leg of the flight was from Idaho Falls to Douglas, Wyoming. The distance was about 336 nautical miles and took 3.7 hours to complete. It required about 27.2 gallons of fuel, for an average burn rate of 7.4 gallons per hour (gph). The flight log indicated that during the first leg of the trip, the fuel selector was on the right tank a total of two hours before the tanks were switched. The second leg was from Douglas, Wyoming, to Wayne, Nebraska. The leg covered about 378 nautical miles and took 4.1 hours to complete. The aircraft was topped off with 31.2 gallons of fuel and the average burn rate was 7.6 gph. The average fuel burn rate for the first two legs of flight was 7.5 gph. The third leg and final leg of the day was from Wayne, Nebraska, to Ames, Iowa. The leg covered about 151 nautical miles and took 1.8 hours to complete. The pilot reported that they made a stopover in Ames. The airplane was not refueled until the next morning. It is not clear exactly how many gallons of fuel were put on the aircraft on Saturday, October 5, 1996. The pilot requested that the aircraft be topped off with fuel. The lineman who serviced the aircraft reported that he opened the left fuel tank and observed that the left tank was full (up to the lip). He replaced the fuel cap and proceeded to top off the right fuel tank. Initially, when the pilot received the bill for refueling, the bill was for 21 or 22 gallons of fuel. But the pilot questioned the amount since the right wing tank held 18 gallons. When the discrepancy was noted, the lineman determined that the bill should have indicated 11 gallons of fuel. However, since the aircraft had been burning an average of 7.5 gph of fuel, the airplane would have required about 13.5 gallons of fuel to be completely topped off after a 1.8 hour flight. It is not clear if the aircraft departed Ames with a total of 36 gallons of fuel on board, or if the aircraft left Ames with 33.5 gallons. The flight log indicated that the aircraft departed Ames at 0930. The log indicated that the fuel selector was on the right tank until 1027, when it was switched to the left tank. The left tank was selected until 1127, when it was switched back to the right tank. The log entry at 1227 reads, "rt tank," not left tank as expected. When the pilot's wife was questioned concerning this, she reported that she was certain that she had intended to write left tank, and that the left tank had been selected. The fuel selector valve was later examined and it was determined that the selector was on the left tank at impact. The aircraft accident occurred at about 1310. The flight from Ames, Iowa, to Silver Lake, Indiana, was about 353 nautical miles and took 3.7 hours. With 36 gallons of fuel, the aircraft had 4.8 hours of fuel on board, assuming a 7.5 gph fuel burn. If the aircraft had 33.5 gallons on board at Ames, the aircraft had about 4.5 hours of fuel on board. In either case, the left fuel tank would have had about 3 to 4.5 gallons remaining when the airplane accident occurred. Witnesses reported seeing the aircraft circling over Silver Lake in a left turn. On the second lap the aircraft began sputtering and then the engine stopped completely. The airplane continued in a left turn. The left wing impacted a pine tree which separated the left wing at about the wing strut attach point. The outboard section of the wing remained in the pine tree. The aircraft continued in an uncontrolled descent and crashed onto the main street and skidded across the road. The aircraft came to a stop with the aircraft resting on its propeller and the tail nearly vertical. People who were nearby rushed to the accident site and aided in removing the pilot and his wife from the airplane. One of the persons assisting at the scene reported smelling fuel, but stated that, "...just a little fuel leaked out." The aircraft was examined by an Airworthiness Inspector of the Federal Aviation Administration (FAA). The examination revealed that there was no indication of fuel leaking near the crash site. The fuel remaining in the right tank was about one half gallon. The left wing fuel tank was still intact and about one half gallon of fuel was drained from the tank. A fuel stain was evident on top of the left wing. The stain initiated from the left wing fuel tank and proceeded back to the trailing edge of the wing. The right wing had no fuel stain. The examination of the aircraft revealed that the engine exhibited continuity. All four cylinders had compression and ignition. The spark plugs were in good condition. The number two cylinder push rods and cylinder were damaged due to impact forces. The flight controls exhibited continuity. One blade of the propeller was bent backwards and the other blade was straight. The preliminary examination revealed that the fuel selector control handle appeared to be in the OFF position. Further investigation revealed that the connecting control rod to the fuel selector was disconnected due to impact damage. The fuel selector valve was examined and the fuel selector valve was verified to be in the left tank position. Photographs of the aircraft taken by the FAA before the aircraft was moved indicated that the fuel stain on the left wing was clearly visible. The stain initiated from behind the fuel cap and proceeded toward the trailing edge of the wing. The stain was about 6 to 8 inches wide at the widest point. The left fuel cap was slightly canted, but the right fuel cap was parallel to the longitudinal axis of the aircraft. The fuel caps had a raised ridge down the center of the fuel cap. When the cap was completely secured, the ridge would be parallel with the longitudinal axis of the aircraft. 8 x 10 inch photographic enlargements of the fuel stain on the left wing were sent to the maintenance personnel who regularly serviced the aircraft for the pilot. They reported that they had not seen a fuel stain like that on the wing before. They reported that the pilot would have had them clean the stain from the wing. The pilot reported that had told the lineman who refueled the aircraft in Ames, Iowa, to top off the fuel tanks. He reported that he did not use a ladder to check the fuel level during preflight. He reported that the fuel caps could be checked by visually observing them from the back of the wing since the aircraft was a taildragger. He reported that the fuel gauges were unreliable since they tended to show low or empty before they really were. He also reported the gauges would indicate the tanks were full when the tanks were actually 3/4 full. The investigation revealed that there were numerous open fields in the area where the accident occurred.

Probable Cause and Findings

fuel starvation due to an inadequate preflight and the pilot performed a low altitude maneuver which prevented him from selecting suitable terrain for landing. Additional factors included the loose fuel cap, fuel siphoning, and unreliable fuel gauges.

 

Source: NTSB Aviation Accident Database

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