HISTORY OF FLIGHTOn September 14, 2022, about 1222 eastern daylight time, a Piper PA-28R-201 airplane, N62FC, was destroyed when it was involved in an accident near Conway, South Carolina. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The flight departed Myrtle Beach International Airport (MYR), Myrtle Beach, South Carolina, about 1205, and was en route to Columbus County Municipal Airport (CPC), Whiteville, North Carolina. Shortly after departure from MYR, the pilot reported to air traffic control (ATC) that he was having problems with the compass, which resulted in difficulty maintaining assigned headings. He stated that he wanted to return to the airport and was not declaring an emergency. About 30 seconds later, the pilot reported a loss of engine power. He informed ATC that he was unable to make it back to MYR and had identified an off-field landing area. Surveillance video captured the airplane as it flew low near trees but did not capture the accident sequence due to a power surge when the airplane impacted a powerline. The airplane first impacted an estimated 40-ft-tall pine tree and then a powerline and came to rest against a berm along a gravel roadway. The right wing and vertical stabilizer separated during the impact with the pine tree and powerline respectively. A postcrash fire ensued that consumed much of the wreckage and back burned to the tree from the initial impact. AIRCRAFT INFORMATIONThe airplane had been at Executive HeliJet Aviation, Myrtle Beach, South Carolina, for avionics upgrades since April 18, 2022. As part of the work being accomplished, the vacuum system was removed and replaced with electronic instrumentation. The Garmin G5 Electronic Flight Instrument Installation Manual states, in part: “The vacuum system and associated parts may be removed if there is no remaining need for vacuum. See the airplane specific maintenance manual and AC 43.13-2B for guidance when removing the vacuum system. If the vacuum pump is removed, the engine accessory port must be properly covered.” A review of the work order revealed that although a vacuum pump plate (P/N 60430) was ordered, there was no reference to the required vacuum pump drive pad gasket being ordered. Figure 1 is a copy of the lubrication schematic for the engine installed in the accident airplane. The red arrows depict the path of the oil from the oil sump to the vacuum pump plate. After the oil traveled through the oil pump, it was pressurized to normal engine operating pressure. Figure 1: Engine Lubrication Diagram from Lycoming Engine Operating Manual According to the engine operating manual, the maximum pressure for engine start, warm-up, taxi, and takeoff was 115 psi. During normal operation, the pressure would be between 55 and 95 psi. As the oil temperature increased, the viscosity is lowered, and the oil will become thin and thus more easily able to escape from non-sealed areas. AIRPORT INFORMATIONThe airplane had been at Executive HeliJet Aviation, Myrtle Beach, South Carolina, for avionics upgrades since April 18, 2022. As part of the work being accomplished, the vacuum system was removed and replaced with electronic instrumentation. The Garmin G5 Electronic Flight Instrument Installation Manual states, in part: “The vacuum system and associated parts may be removed if there is no remaining need for vacuum. See the airplane specific maintenance manual and AC 43.13-2B for guidance when removing the vacuum system. If the vacuum pump is removed, the engine accessory port must be properly covered.” A review of the work order revealed that although a vacuum pump plate (P/N 60430) was ordered, there was no reference to the required vacuum pump drive pad gasket being ordered. Figure 1 is a copy of the lubrication schematic for the engine installed in the accident airplane. The red arrows depict the path of the oil from the oil sump to the vacuum pump plate. After the oil traveled through the oil pump, it was pressurized to normal engine operating pressure. Figure 1: Engine Lubrication Diagram from Lycoming Engine Operating Manual According to the engine operating manual, the maximum pressure for engine start, warm-up, taxi, and takeoff was 115 psi. During normal operation, the pressure would be between 55 and 95 psi. As the oil temperature increased, the viscosity is lowered, and the oil will become thin and thus more easily able to escape from non-sealed areas. WRECKAGE AND IMPACT INFORMATIONDuring the impact with the pine tree, the right wing and right horizontal stabilizer separated from the airframe. During a postaccident examination of the airframe, flight control continuity was established from the cockpit to the left aileron, stabilator, and rudder control surfaces. When the bottom of the empennage was examined, a sizeable quantity of oil was present near the tail tie down ring. A postaccident examination of the engine revealed that the Nos. 2, 3, and 4 connecting rods were separated from the crankshaft. The left engine crankcase half was fractured inboard of the No. 4 cylinder mounting pad. The Nos. 3 and 4 connecting rods were separated from their respective crankshaft rod journals and the damaged rod ends were visible through the crankcase fracture. During disassembly of the engine, a vacuum pump cover (item No. 13 in Figure 2 below from the Lycoming Parts Catalog) was removed from the vacuum pump drive pad and no gasket (item No. 11), or remnants of a gasket, were found. Other engine components were removed, and all had remnants of a gasket despite the thermal damage. Figure 2: Excerpt from Lycoming Parts Catalog, View of Engine Accessory Case A review of the aircraft maintenance records revealed that after one certificated airframe and powerplant mechanic had completed the work on the airplane, the Director of Maintenance, an airframe and powerplant mechanic with inspection authorization, signed off to return the airplane back to service. The return to service logbook entry stated that the vacuum pump had been removed but did not address the installation of the drive pad gasket or vacuum pump cover. Additionally, there was no mention of an engine runup following completion of the work. In an interview, the mechanic who completed the removal of the vacuum pump and installation of the vacuum pump cover stated that when he removed the vacuum pump, the gasket was still attached to it. He cleaned the mating surface of the cover and drive pad with Scotch-Brite and then installed the cover. He stated that he thought he had replaced the gasket. When asked about the performance of an engine runup, he stated that he ran the engine for about 30 minutes after the installation of the avionics modification. He did not recall seeing any oil leaks following the runup and said that before the runup there were about 7.5 quarts of oil in the engine and a “few days later” checked it again and the level was still above 7 quarts. When asked if there was more than one mechanic working on the modification, he said that other mechanics would come in and help complete some tasks while he concentrated on the wiring. The Director or Maintenance was asked how he reviewed completed work before returning the airplane to service, to which he replied, “I look at it all.” He stated that on larger jobs he would conduct his inspection in stages by reviewing one area when the mechanic completed an area such as the cockpit or engine and moves to another area.