Aviation Accident Summaries

Aviation Accident Summary WPR18LA194

Salisbury, NC, USA

Aircraft #1

N8440F

Piper PA32

Analysis

The pilot departed with his passengers on a cross-country flight with the main and auxiliary fuel tanks at full capacity. About 2 hours and 18 minutes into the flight, the engine lost total power. The pilot was unable to restart the engine and declared an emergency. The controller provided vectors to a nearby airport, where the airplane landed hard, resulting in substantial damage. First responders reported that they drained about 55 gallons of fuel from the airplane after the accident and an additional, unquantified amount spilled onto the ground; however, the fuel was drained before the airplane could be examined and the amount of fuel onboard and its distribution at the time of the accident could not be confirmed. Data retrieved from an onboard engine monitoring system showed erratic fuel flow indications concurrent with a sudden decrease in exhaust gas temperatures. These erratic fuel flow indications suggest the possibility that the transducer was pulling in air due to an interruption in fuel flow, which may have been the result of fuel starvation or an introduction of air within the fuel system upstream of the transducer. The fuel lines were not tested, as they had been cut by recovery personnel. A postaccident examination of the engine revealed no fuel in the line between the engine-driven fuel pump and the fuel servo, which typically captures and retains unused fuel destined for the engine. A subsequent engine run revealed no anomalies of the engine. Given the available information, it is likely that the loss of engine power was the result of fuel starvation; however, whether the fuel starvation was the result of fuel mismanagement or an introduction of air into the fuel system could not be determined.

Factual Information

On June 29, 2018, about 1603 eastern daylight time, a Piper PA-32-300, N8440F, was substantially damaged when it was involved in an accident near Salisbury, North Carolina. The private pilot and two passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. On the morning of the accident, the pilot and passengers departed New York for North Carolina. The pilot refueled the airplane with 24 gallons of fuel during an intermediate stop; before departing, he completed a preflight inspection and an engine run-up, which revealed no anomalies. Shortly after departure, the pilot decided to return to the airport to inspect the left-wing fuel cap. After landing and confirming that the fuel cap was secured, the pilot departed again and climbed to a cruise altitude of 6,500 ft mean sea level (msl). About 2 hours into the flight, the engine slowed to 1,500 rpm and 15 seconds later, the engine lost total power. The pilot activated the fuel pump, applied full rich mixture, and checked both magnetos, but was unable to restart the engine and declared an emergency with air traffic control. The controller advised the pilot of an airport about 7 nautical miles from his position. The pilot subsequently landed on the grass between a runway and taxiway, as there was a construction crew repaving the runway. During the landing, the right main landing gear impacted the ground first and the airplane jerked to the right before coming to rest in the grass. Examination by a Federal Aviation Administration (FAA) inspector revealed substantial damage to the engine firewall and left wing. Both the main and auxiliary fuel tanks were drained before his arrival at the accident site. First responders reported that they drained a total of 55 gallons of fuel from the airplane immediately after the accident and estimated that about 25 gallons of fuel had spilled on the ground. The airplane was equipped with an engine monitoring system that captured numerous parameters, including fuel flow, engine rpm, exhaust gas temperature (EGT), and cylinder head temperature (CHT). The data was downloaded by the National Transportation Safety Board Recorders Laboratory. The EGT values for each cylinder and engine rpm were consistent for the majority of the flight until about 1559:10, when the EGTs dropped from about 1,500º F to about 300º F and continued to decrease and fuel flow values became erratic. At 1559:30, the engine rpm decreased from 2,400 rpm to about 1,600 rpm and stabilized for 30 seconds before further decreasing to 1,300 rpm. At 1601:45, the fuel flow spiked to about 117 gph and then rapidly fell to 20 gph, at which point the data track ended. The engine rpm then advanced to 1,700 rpm about 1602, before rapidly decreasing to idle power at 1603:35. According to a representative of the fuel flow transducer manufacturer, erratic fuel flow indications can be representative of the unit intaking air, radio frequency interference, or a poor connection between the transducer and the reading instrument. Review of maintenance logbooks revealed that the airplane's most recent annual inspection was performed on September 16, 2017 at 3,661 hours total time in service, about 81 flight hours before the accident. At the time of the inspection, the engine had accumulated a total of 1,660hours since its most recent overhaul. The airplane was equipped with two main fuel tanks, located inboard in each wing, with a total capacity of 50 gallons. The airplane was also equipped with two auxiliary fuel tanks located on the wingtips, with a total capacity of 84 gallons. The airplane's Pilot's Operating Handbook stated, "…lateral trim is best maintained by using fuel alternatively from each main tank, and when these are nearly exhausted, from each tip tank. It is recommended that one main tank be used for one hour after takeoff, the other main tank used until nearly exhausted, then return to the first main tank. When nearly exhausted, turn to one tip tank and alternate at one-half hour intervals to maintain lateral trim." Examination of the airplane revealed that the top and bottom engine cowlings were intact and attached to the forward fuselage. Both propeller blades were bent, and the nose landing gear was crushed and folded aft. The engine controls were intact and continuous from the cockpit to the engine. The fuel tanks were intact. The fuel gascolator bowl contained a trace amount of 100 low lead aviation grade fuel and the fuel gascolator screen did not display any contaminants. Each of the fuel lines downstream of the electric fuel pump were opened and did not display any liquid. The upstream fuel lines were not inspected or tested as they had been cut by recovery personnel. The fuel selector valve moved normally through each of its detents and was found in the left tank position. Mechanical continuity was established throughout the engine and valvetrain when the engine was rotated by hand. As the engine was rotated, the left magneto impulse coupling was heard (the right magneto was not equipped with an impulse coupling). Fuel was plumbed into the airframe fuel pump to facilitate an engine test run. The engine started normally and ran for several minutes at various power settings between idle and 1,800 rpm. During this time, oil pressure, fuel pressure, fuel flow, manifold pressure, alternator output, and pneumatic pressure all displayed normal indications. Based on the pilot's reported fuel management procedure of changing tanks every 30 minutes, the airplane would have had about 11 gallons of fuel in the right main tank and 8 gallons in the left main tank at the time of the power loss. However, the left main tank would have been nearly void of fuel had the pilot omitted his procedure to switch to the right fuel tank only once. Further, the fuel selector was found at the accident site in the left tank detent. According to the pilot, he used a combination of reminders on his watch and the Garmin GPS display, which issued a warning to him every 15 minutes to remind him to switch fuel tanks.

Probable Cause and Findings

A total loss of engine power due to fuel starvation for reasons that could not be determined based on the available information.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports