Mechanic’s error fatal for two — General Aviation News

By NTSB · September 18, 2024 · 17 Comments

The flight departed Myrtle Beach International Airport (KMYR) in South Carolina and was en route to Columbus County Municipal Airport (KCPC) in Whiteville, North Carolina.

Shortly after departure from KMYR, 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, he reported a loss of engine power. He informed ATC that he was unable to make it back to KMYR and had identified an off-field landing area near Conway, South Carolina.

Surveillance video captured the Piper PA-28R-201 as it flew low near trees but did not capture the accident due to a power surge when the airplane hit a powerline.

The plane first hit an estimated 40-foot-tall pine tree and then a powerline and came to rest against a berm along a gravel road. The right wing and vertical stabilizer separated during the accident. A post-crash fire ensued that consumed much of the wreckage.

The pilot and a passenger died in the crash.

A post-accident 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 crankshaft rod journals and the damaged rod ends were visible through the crankcase fracture.

During disassembly of the engine, a vacuum pump cover was removed from the vacuum pump drive pad but no gasket, or remnants of a gasket, were found. Other engine components were removed, and all had remnants of a gasket despite the thermal damage.

The plane had been at a shop in Myrtle Beach for several months for an avionics upgrade.

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 was ordered, there was no reference to the required vacuum pump drive pad gasket being ordered.

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 run-up 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 run-up, 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 run-up and said that before the run-up 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 of 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.

Probable Cause: The mechanic’s failure to install the required gasket on the vacuum pump drive pad in accordance with the maintenance manual, which resulted in oil exhaustion and the subsequent loss of engine power. Contributing to the accident was the Director of Maintenance’s failure to verify the installation of the vacuum pump gasket before returning the airplane to service.

NTSB Identification: 105936

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This September 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.