Randy Hunter reported mechanical trouble almost immediately after taking off from the Savannah airport Aug. 28.

A preliminary report from the federal agency investigating a plane crash that killed the metro Atlanta pilot and the Savannah couple he was flying might explain the mechanical failure, according to an aviation expert.

The plane was carrying Byron Cocke, a prominent 42-year-old metro Atlanta real estate developer, and his wife 39-year-old Catherine Cocke, an interior designer once featured on HGTV, when it crashed while heading to Cobb County International Airport-McCollum Field.

Peter Knudson, a spokesman with the National Transportation Safety Board, said Monday that the investigation could take between a year and two years.

The NTSB report said the Beechcraft Bonanza, a fixed-wing single-engine aircraft, was destroyed when authorities found it in rural Bryan County about 150 feet from the Ogeechee River. The wings were still attached, but it sat 10 feet from where it impacted the ground.

John Cox, an aviation accident investigator of 30 years, read the report and pointed to a 51-word paragraph at the end as illuminating what might have happened.

It reads: “Examination of the engine revealed a hole in the top right rear of the engine case that was about 2 inches in diameter. The crankshaft was visible through the hole and there was no connecting rod attached to the visible rod journal. The engine was retained for a future teardown examination.”

This is the charter plane that crashed near Savannah, killing its two passengers and the pilot the morning of Monday, Aug. 28, 2017.

Cox explained that, much like automobiles with a series of pistons and cylinders that move a crank shaft that powers the transmission, the Bonanza has the same system that powers a propeller.

And, according to him, it was one of plane’s crank shafts that was missing.

“One of those rods … appears to have come out puncturing a hole in the engine casing, which would cause the engine to fail,” he said. “ ... It’s an ugly failure.”

The report said the plane was destroyed upon impact, so when asked if this damage could have happened during the crash, Cox said this type of rare failure is more consistent with happening mid-air.

“That means the engine has catastrophically failed,” he said.

Cox said it should be obvious to the NTSB when they tear down the engine to determine what killed Hunter and the Cockes.

The Savannah couple leave behind five children, according to a spokeswoman with Byron Cocke’s metro Atlanta company CF Real Estate Services.

"Our thoughts and prayers are with the Cocke family who also lost two beloved and cherished family members in this tragic accident," Hunter's wife previously said in a statement.

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