Aviation Accident Summaries

Aviation Accident Summary MIA06LA062

Brooksville, FL, USA

Aircraft #1

N9138C

Cessna 180

Analysis

The pilot stated that he had topped off the airplane's fuel tanks in Gallatin, Tennessee, and he had 60 gallons of fuel onboard. He departed at 0625 central daylight time, climbed to 9,000 feet, and the flight's duration was 3 hours 30 minutes. He said he leaned the fuel mixture, observing fuel flows of about 10.5 to 11gallons per hour on his JPI analyzer, and that the quantity of fuel remaining never was less than 20 gallons. Upon reaching his destination airport he said he over-flew the airport to observe the winds, and then flew 6 miles south, twice circling his friend's house, and then returned to land. During the approach, while turning to base he applied 30 degrees of flaps, at which time the engine ceased operating. He said obstacles included trees and utility wires, and during the glide, after avoiding the trees, he selected 40 degrees of flaps in an attempt to balloon over the wires, and the airplane stalled and descended impacting the ground. During the pilot's report of the accident to the NTSB he stated that there were no mechanical failures or malfunctions to the airplane or any of its systems. A witness stated that he saw the accident airplane on downwind, rocking its wings, and he saw it on final approach and as it came over the trees. He said the propeller had stopped rotating, and as he continued watching, it appeared as if the pilot was trying to stretch the glide. He said he saw the airplane stall and descend, impacting the ground a short distance from the runway. On the day of the accident, an FAA inspector responded to the scene of the accident and found no evidence of fuel spillage at the scene. When the airplane was checked, the inspector found about 2 gallons of fuel in the left tank, and no fuel in the right tank. On March 10, 2006, an FAA licensed mechanic, under the supervision of the FAA inspector, conducted a detailed examination of the airplane's airframe and engine, and no anomalies were noted. The accident airplane was equipped with a Texas Skyways Incorporated conversion O-520 -U/TS engine. On July 17, 2007, a technician at Texas Skyways stated to the NTSB that Texas Skyways did not publish endurance documentation for their conversions because of the various models of engines they modified, and their variability in fuel consumption. He further stated that from his experience, climb to cruise fuel consumption for the O-520 U/TS engine, at a rate of climb of about 1,000 feet per minute, at full power, without leaning for changes in altitude would yield a fuel consumption of about 23 gallons per hour. He further stated that with leaning the mixture, and with other climb related adjustments, the average fuel consumption during the climb should be about 18 gallons per hour. At an altitude of 9,000 feet, the technician also estimated that the airplane should consume about 14 gallons per hour, while in cruise flight. In addition, the technician also said that JPI endurance data was consistent with the exhaust and cylinder head temperatures noted.

Factual Information

On March 4, 2006, about 1055 eastern daylight time, a Cessna 180, N9138C, registered to and operated by a private individual as a Title 14 CFR Part 91 personal flight, crashed short of the runway following loss of engine power at Brooksville, Florida. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed. The airline transport-rated pilot received serious injuries, and the airplane incurred substantial damage. The flight originated in Gallatin, Tennessee, the same day about 0725. The pilot stated that he had topped off the airplane's fuel tanks in Gallatin, Tennessee, the day before the accident flight. He said on the day of the accident flight, he performed a preflight inspection of the airplane and found both fuel tanks full, with 60 gallons of fuel onboard. He said he departed at 0625 central daylight time, and that his airplane was equipped with a new engine, propeller, a JPI analyzer, and digital tachometer, which made it operate efficiently. He further stated that upon departure he climbed to 9,000 feet, and the flight's duration was 3 hours 30 minutes, with him noticing fuel flows of about 10.5 to 11 gallons per hour on his JPI analyzer. He said that the quantity of fuel remaining as displayed on the JPI analyzer never became less than 20 gallons. According to the pilot, the highest fuel consumption he saw was in the past, when the engine conversion had been new, and when he had operated the engine at a rich power setting, and at that time the highest consumption while in cruise flight at low altitudes was15.3 gallons per hour. Upon reaching his destination airport he said he over-flew the airport to observe the winds, and then flew 6 miles south, twice circling his friend's house, and then returned to land. Upon preparing to land, he decided to perform a short field approach, and applied 30 degrees of flaps, while turning to base, at which time the engine ceased operating. He said obstacles included trees and utility wires, and during the glide, after avoiding the trees, he selected 40 degrees of flaps in an attempt to balloon over the wires, but the airplane stalled and descended impacting a pond embankment, incurring substantial damage. The pilot's report of the accident to the NTSB states that there were no mechanical failures or malfunctions to the airplane or any of its systems. The pilot later submitted information asserting that the airplane should have had in excess of 20 gallons remaining in its fuel tanks at the end of the flight. In addition, the pilot submitted a picture which he believed shows signatures of fuel related leaks on the wing, which he asserts occurred during flight. A witness stated that he was in an office building at the airport, looking out the window, and he saw the accident airplane on the downwind leg, rocking its wings. He further stated that he observed the airplane final approach, he saw the airplane come over the trees, and the propeller had stopped rotating. He said as he continued watching, it appeared as if the pilot was trying to stretch the glide, and he saw the airplane stall and descend, impacting the ground a short distance from the runway. On the day of the accident an FAA inspector responded to the scene of the accident. The inspector stated that he found no evidence of fuel spillage at the scene. The inspector further stated that when the airplane was checked, he found about 2 gallons of fuel in the left tank, and no fuel was found in the right tank. On March 10, 2006, an FAA licensed mechanic, under the supervision of the FAA inspector, conducted a detailed examination of the airplane's airframe and engine, and no anomalies were noted. The accident airplane was equipped with a Texas Skyways Incorporated conversion O-520 -U/TS engine. On July 17, 2007, a technician at Texas Skyways stated to the NTSB that Texas Skyways did not publish endurance documentation for their conversions because of the various models of engines they modified, and their variability in fuel consumption. He said that based upon his experience, climb to cruise fuel consumption, at a rate of climb of about 1,000 feet per minute, at full power, without leaning for changes in altitude would yield a fuel consumption of about 23 gallons per hour. He further stated that with leaning the mixture, and with other climb related adjustments, the average fuel consumption during the climb should be about 18 gallons per hour. At an altitude of 9,000 feet the technician estimates that the airplane should consume about 14 gallons per hour, while in cruise flight. The technician also said that the JPI endurance data was consistent with the exhaust and cylinder head temperatures noted in the data.

Probable Cause and Findings

An in-flight loss of fuel for undetermined reasons which resulted in fuel exhaustion, a forced landing and damage to the airplane during the landing.

 

Source: NTSB Aviation Accident Database

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