Primary finding
Probable cause
The pilot’s failure to determine the airplane’s fuel quantity before takeoff, which resulted in a loss of engine power due to fuel exhaustion.
Investigator assessment
Analysis narrative
On the day of the accident, the pilot reported that he expected the borrowed airplane’s fuel tanks to be full. Since there was no ladder available to visually view the fuel tank quantity or to use a dip stick, he relied on the fuel gauges, which indicated that the left tank was about 3/8 full and the right fuel gauge indicated full. After accomplishing two parachute drops, an individual asked the pilot to take him and his children on a local sightseeing flight. During that flight, the engine lost power and the pilot subsequently made a forced landing to a field. During the wreckage recovery, personnel reported that neither fuel tank was breached and that the tanks were empty, suggesting that the loss of engine power was due to fuel exhaustion. Throughout the day, the airplane’s fuel quantity gauges gave indications that suggested the tanks contained fuel, and the pilot, therefore, continued to fly the airplane without visually inspecting the quantity of fuel in the tanks. Postaccident examination and testing of the fuel quantity indicating system did not reveal any mechanical malfunctions or failures that would preclude normal operation. The pilot who previously flew the airplane reported that, although the protocol was that all individuals who borrowed the airplane were to fill its fuel tanks after using it, he had failed to do so and left about 5 gallons of fuel in one tank and about 3 gallons of fuel in the other.
Source record
Factual narrative
On June 18, 2011, about 1300 mountain daylight time, a 1983 Cessna 172P, N65654, impacted the terrain about three miles northeast of Mount Pleasant Airport, Mount Pleasant, Utah. The private pilot and one of his passengers received serious injuries, and the other three passengers received minor injuries. The airplane, which belonged to a friend of the pilot, sustained substantial damage. The local 14 Code of Federal Regulations Part 91 personal pleasure flight, which departed Mount Pleasant Airport about 15 minutes prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the pilot, the original reason for using the airplane that day was that his son had been asked to make a parachute jump at the Rocky Ridge, Utah, Town Days celebration. The pilot therefore borrowed his friend’s airplane, which was kept at South Valley Regional Airport, near West Jordon, Utah. After his son removed the right front seat from the airplane in order to facilitate the parachute jump, the pilot departed South County Regional Airport and flew to Rocky Ridge, a distance of about 49 miles. After some minimal maneuvering at Rocky Ridge, the pilot’s son made the parachute jump. And then, because there is no airport directly associated with the town of Rocky Ridge, the pilot continued on to Nephi Municipal Airport, Nephi, Utah, which is about 14 miles south of Rocky Ridge. The pilot waited at Nephi while his son repacked his parachute and got a ride down to the Nephi Airport. While the pilot was waiting at Nephi, he received a phone call from a friend of his who lived in Mount Pleasant, Utah, which is located about 25 miles southeast of Nephi Municipal Airport. That individual asked the pilot if it would be possible if his son could make a parachute jump that same day into a field near his house in Mount Pleasant. When the pilot’s son arrived at Nephi Municipal Airport, the pilot asked him if he would like to make the second jump at Mount Pleasant, and his son said that he would. The pilot therefore took off and flew the 25 miles to Mount Pleasant. After arriving in the Mount Pleasant area, the pilot flew down low over the field behind his friend’s house in order to make sure it was a safe place for his son to parachute into. He then climbed up to 9,800 feet mean sea level (MSL), which was about 4,000 feet higher than the elevation at the field. After some minor maneuvering for alignment, the pilot’s son parachuted from the airplane and successfully landed in the designated field. The pilot then flew about three miles south and landed at the Mount Pleasant Airport. When his friend arrived at the airport with the pilot’s son, the friend had his wife and their three children with him, and he asked the pilot if he could take him and the children for a short ride around the area. Since the pilot’s son still had to pack his parachute, the pilot agreed to take his friend and the three children for a flight around the immediate area. The three children were put in the two-person rear seat, with the youngest two sharing one seatbelt and the older child using the second seatbelt. The pilot used the belt portion of his 3-point restraint system, and the pilot’s friend kneeled on the floor where the right front seat had been, and reportedly did not use any of the restraint system. The pilot then took off from Mount Pleasant Airport, flew over his friend’s house, then along a nearby ridge. His friend then asked the pilot if they could descend lower so he could take a closer look at a campground near his home. In response, the pilot reduced the power and descended toward the campground. As the pilot started to level off to pass by the campground, the airplane’s engine sputtered and stopped. The pilot then moved the fuel selector from the BOTH position to the right tank, and after priming the engine, attempted a restart. Since the restart was unsuccessful, he then switched to the left fuel tank, primed the engine, and again tried a restart. The pilot then turned toward the airport, lowered the flaps to about 15 degrees, and tried another restart with the selector on the BOTH position. Ultimately realizing that he was not going to make it to the airport, the pilot headed for a nearby road, but when a couple of cars appeared on the road, he elected to land in an open field alongside the road. As the airplane was touching down, it impacted a number of large sagebrush bushes and its right main gear impacted a rock, resulting in a deceleration rate that caused both the pilot and his friend to hit the airplane’s instrument panel hard. During the investigation it was determined that the owner of the airplane allowed a small group of his friends to fly the airplane at no cost, as long as they filled up the fuel tanks prior to putting it back in the hangar. Except for one individual, each one of the friends had to call the owner to schedule a time to use the airplane, and then they had to acquire the key to the hangar. One of the friends, who was a former partner in the airplane, had his own key to the hangar, and therefore was able to use the airplane with or without the owner’s knowledge. That individual flew the airplane without the owner’s knowledge on the day prior to the accident flight, and since his passenger was in a hurry to get going after the flight, he did not refuel the airplane prior to putting it back into the hangar. Although he did use the dip stick to measure the fuel in each tank after the flight, he did not make it back to the airport to refuel the airplane before the airplane was used again the next morning. Since the owner did not know that the airplane had been flown on the day prior to the accident, when the accident pilot called to get permission to use the airplane, the owner told him that it should be full of fuel (although according to the owner, he expected the pilot would use the dipstick to check the tanks prior to flight). Therefore, according to the dipstick measurements made by the pilot at the end of the flight on the previous day, when the accident pilot arrived at the hangar around 0800 on June 18, the airplane had about five gallons of fuel in one tank and about three gallons in the other. Although the pilot drained a small amount of fuel out of each tank to check for clarity and for the correct color, he did not physically removed the fuel tank caps to look inside, nor did he use the dipstick that was in the airplane to measure the quantity in each tank. When asked by the NTSB Investigator-In-Charge (IIC) why he had not done so, the pilot stated that he had looked around the hangar to find something safe to stand on to gain access to the top of the wings, but that he was unable to find a suitable object. He therefore relied on the fuel quantity gauge indications to determine the approximate amount of fuel that was present, and, according to the pilot, when he pulled the airplane out of the hangar and turned the power switch on, the left gauge indicated about 3/8th full and the right gauge indicated near full. During the IIC’s phone interview with the pilot, he stated that shortly after he took off from Nephi, both fuel quantity gauges indicated almost empty (although in his written statement he said that only the right fuel quantity gauge indicated near empty, and that the left indicated about 5/8th full). The pilot therefore made the decision to turn back to Nephi, but as he did so, the left fuel quantity gauge reportedly returned to near the ½ full mark, and the right gauge reportedly stayed near the 5/8 full position. The pilot therefore turned toward Mount Pleasant, and continued to his destination. When asked by the IIC what the fuel quantity indications were just prior to his takeoff from Mount Pleasant, the pilot stated that he did not remember if he had rechecked what the fuel quantity indications were at that point, and was therefore unabl