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NTSB investigation record

ERA22FA026

Completed

Piper Pa-32R-300· N1652H

Date
October 22, 2021
Location
Walterboro, SC
Conditions
VMC
Record
Published December 20, 2023

Primary finding

Probable cause

The pilot’s inadequate fuel planning and fuel management, which resulted in a loss of engine power due to fuel starvation.

Investigator assessment

Analysis narrative

The airplane departed from its home airport for an airport about 802 nautical miles away with the airplane’s fuel tanks filled to their total fuel capacity of 98 gallons. The pilot planned for the flight to only be a single leg, but about 1.5 hours into the flight he decided to land for fuel due to the 20-knot headwind, which he had not accounted for during his flight planning. About 2 hours and 53 minutes into the flight, the pilot advised air traffic control (ATC) that he wanted to divert for fuel and then resume his instrument flight rules (IFR) flight plan to his destination. The air traffic controller cleared the pilot to fly direct to a diversion airport. When the airplane was approximately nine miles north of the diversion airport, at an assigned altitude of 1,600 feet msl, the pilot declared “Mayday” and reported a “lagging engine.” The pilot described that, when he reached 1,600 feet, he pushed the throttle forward to level off from the preceding descent, but the engine did not respond. The engine then surged (went up and back down), but it would not respond to his throttle inputs. The airplane subsequently impacted trees short of the diversion airport. During the impact sequence, the pilot was seriously injured and the passenger was fatally injured. The pilot had flown for about 3 hours, and 351 miles of the 802-mile flight, at the time of the accident. Fuel consumption calculations indicated that, depending on the power setting, more than half of the fuel load of 94 gallons of usable fuel would have been consumed before the accident (about 47.7 to 56.7 gallons, depending on power setting). This was greater than the usable fuel amount in each wing (47 gallons per side). While the pilot stated that he checked the fuel gauges every 15 minutes and would continue flying on the fuel tank that had the higher fuel indication, the Pilot’s Operating Handbook (POH) for the airplane, advised that to keep the airplane in best lateral trim during cruise flight, the fuel should be used alternately from each tank at one-hour intervals. The POH also stated, “Always remember that the electric fuel pump should be turned "ON" before switching tanks and should be left on for a short period thereafter. To preclude making a hasty selection, and to provide continuity of flow, the selector should be changed to another tank before fuel is exhausted from the tank in use. If signs of fuel starvation should occur at any time during flight, fuel exhaustion should be suspected, at which time the fuel selector should be immediately positioned to a full tank and the electric fuel pump switched to the "ON" position.” Postaccident examination of the airplane at the accident site revealed the postimpact fire had a burn pattern that appeared to initiate from the area of the right wing. Residual fuel was found in the right outboard fuel tank, and fuel staining was also present around the fuel filler port for the right wing. However, minimal thermal damage was present on the inboard leading edge of the left wing, and residual fuel and fuel staining were not evident. This physical evidence suggests that little or no fuel was present in the left wing fuel tanks, and that the majority of the fuel onboard the airplane at the time of the accident was in the right wing tanks. The postaccident examination of the engine did not reveal evidence of any preimpact failures or malfunctions that would have precluded normal operation. Based on this information, it is likely that the loss of power was due to the left wing having little or no usable fuel available, which subsequently introduced air into the fuel lines. Thus, after the loss of power, the fuel in the right wing would not have been a reliable source of fuel to quickly restore engine power. Based on the available evidence, the circumstances of the accident are consistent with fuel starvation resulting from the pilot’s mismanagement of the fuel system during the flight.

Source record

Factual narrative

Maintenance Records A review of partial copies of the airplane’s maintenance logbook entries had revealed that the engine had accumulated 2083.76 hours at the time of the most recent annual inspection dated August 5, 2021. According to maintenance records, the airplane's most recent annual inspection was completed on August 5, 2021. At the time of the inspection, the airplane had accrued about 6,050 total hours of operation, and the engine had accrued about 2,084 hours since major overhaul.” Fuel System The fuel system consisted of two interconnected tanks in each wing, having a combined capacity of 49 U.S. gallons, for a total capacity of 98 U.S. gallons (94 usable). Fuel flow was indicated on a gauge located in the instrument panel. A fuel quantity gauge for each wing system was also located in the instrument panel, which indicated the amount of fuel remaining as transmitted by the electric fuel quantity sending units located in the wing tanks. An exterior sight gauge was installed in the inboard tank of each wing so fuel quantities could be checked on the ground during the preflight inspection of the airplane. Fuel was drawn through a finger screen located in the inboard fuel tank and routed to a three-position fuel selector valve and filter unit which was located aft of the main spar. The valve had “OFF,” “LEFT,” and “RIGHT” positions that were remotely selected by means of a torque tube operated by a handle located in the pedestal. The handle had a spring-loaded detent to prevent accidental selection to the “OFF” position. From the selector valve the fuel would go to the electric fuel pump, which also was mounted aft of the main spar and then would go forward to the engine-driven fuel pump, which forced the fuel through the injector unit into the engine. Guidance for Fuel Tank Selection According to the Pilot’s Operating Handbook (POH) for the airplane, to keep the airplane in best lateral trim during cruise flight, the fuel should be used alternately from each tank at one-hour intervals. The POH also stated, “Always remember that the electric fuel pump should be turned ‘ON’ before switching tanks and should be left on for a short period thereafter. To preclude making a hasty selection, and to provide continuity of flow, the selector should be changed to another tank before fuel is exhausted from the tank in use. The electric fuel pump should be normally ‘OFF’ so that any malfunction of the engine driven fuel pump is immediately apparent. If signs of fuel starvation should occur at any time during flight, fuel exhaustion should be suspected, at which time the fuel selector should be immediately positioned to a full tank and the electric fuel pump switched to the ‘ON’ position.” At the time of the accident, the pilot was a colonel in the United States Air Force, was rated as a command pilot, and had flown the T-37A, T-38A, C-130E, AT-38B, F-16C, A-10A, and A-10C. According to Federal Aviation Administration (FAA) records, the pilot held a commercial pilot certificate, with ratings for airplane single-engine land, airplane multi-engine land, and instrument airplane. His most recent FAA second-class medical certificate was issued on October 20, 2021. At the time of the accident, he had accrued approximately 1,968 total flight hours, of which about 76 hours were in the accident airplane make and model. On October 22, 2021, about 1557 eastern daylight time, a Piper PA-32R-300 airplane, N1652H, was destroyed when it was involved in an accident near Walterboro, South Carolina. The pilot was seriously injured, and the passenger was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The airplane departed on an 802 nautical mile flight from Shannon Airport (EZF), Fredericksburg, Virginia, about 1256 destined for Miami Executive Airport (TMB), Miami, Florida. Before departure, the pilot brought the airplane’s fuel tanks up to their total fuel capacity of 98 gallons by adding 78.81 gallons of 100LL aviation gasoline. The flight was uneventful until about 2 hours and 53 minutes into the flight, when the airplane was in cruise at 6,000 feet above mean sea level (msl). The pilot advised air traffic control (ATC) that he wanted to divert to Lowcountry Regional Airport (RBW), Walterboro, South Carolina, for fuel, and then resume his IFR flight plan to TMB. The air traffic controller then cleared the pilot to fly direct to RBW and approved him to leave the frequency to get the current weather and NOTAMS for the airport. When the pilot reported that he was back on frequency, the air traffic controller instructed him to maintain 3,000 feet msl and to state his approach request. The pilot requested the visual approach to runway 23. The air traffic controller then instructed the pilot to maintain 1,600 feet msl, and subsequently instructed him to fly heading 190° to the RBW Airport. The airplane was approximately nine miles north of RBW when the airplane began to descend without a clearance. The pilot then declared “Mayday” and reported a “lagging engine” to which the air traffic controller advised that RBW was at one o’clock and seven miles, and to maintain present heading and altitude. The minimum safe altitude warning then activated at the air traffic controller’s station as the airplane descended through 1,000 feet msl. The air traffic controller queried the pilot if they were reporting a rough running engine, to which there was no response. The airplane continued descending while in a left turn to the northeast and was last observed by ATC radar at an altitude of 100 feet msl. There was no further communication with the pilot. According to a witness, he heard an airplane “sputter and stop.” He looked in the direction of the airplane, and continued to hear sputtering, before the sound of an engine cut out, and then sputtering again. The airplane kept flying and then went out of sight. According to two other witnesses, about 1556, they began to hear an engine noise. They observed [the accident airplane] almost directly above the tree line behind their neighbor’s house. It appeared to be in a left turn, and then they next heard a loud “pop” from the airplane and the engine noise ceased. According to the pilot, once he arrived at the airport, he pulled the airplane out of the hangar with his tug, loaded their baggage, boarded the airplane, and then started the engine. He then taxied to the fuel pumps. He filled both wing tanks all the way up (just below the caps). He then took off. The weather was VMC and he had filed an instrument flight rules flight plan. He planned to cruise at 6,000 feet and he could not remember if he changed altitude at any time during the cruise portion of the flight. He had filed the flight as one leg. About 1.5 hours into the flight, he decided to land for fuel due to the headwinds he encountered. He had also made the decision to get fuel early, as he would be landing at his destination at night. He received the weather for the diversion airport and, as he was proceeding to the airport, he received a clearance to descend to 1,600 feet. He began the descent and pulled the power back. When he reached 1,600 feet, he pushed the throttle forward, but the engine did not respond. He then pulled it back towards idle to try and match the throttle to where the engine was operating. The engine surged (went up and back down). He pushed the throttle forward, but there was no response. He then pitched the airplane to get the speed to about 90 knots (towards best glide). He then declared an emergency and when they were about 100 feet above the trees, he lowered the landing gear. He told the passenger to “Brace” as they were going to crash and transmitted: “Mayday, Mayday, Mayday” before the airplane contacted the trees. He could not remember anything after hitting the trees. The next thing

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