National Transportation Safety Board investigators say Greg Biffle was not at the controls of his business jet during last month's fatal crash near Statesville (N.C.) Regional Airport, a finding that reshapes early assumptions while raising new questions about cockpit staffing and a cascade of instrument issues.

The agency's preliminary report states that Dennis Dutton, a retired airline pilot, flew the airplane with his son Jack Dutton seated in the right seat. Biffle, a licensed pilot with extensive experience, was on board but was not the one flying.

Investigators concluded that neither Biffle nor Jack Dutton held the necessary endorsement on their pilot's licenses to serve as second-in-command on the Cessna Citation 550 – a two-pilot operation under Federal Aviation Administration rules.

The flight lasted roughly 10 minutes. Problems surfaced before takeoff with an inoperative thrust reverser indicator light, then escalated after departure when the left-side altimeter and other instruments stopped working. The pilot briefly handed control to the right seat while troubleshooting the problems.

Investigators said cockpit audio cut out at times, and it remains unclear why the jet approached low enough to clip landing-light poles before erupting in a fireball. The crash killed Biffle; his wife, Cristina; their children Ryder and Emma; friend Craig Wadsworth and the two Duttons.

Biffle was a longtime presence in NASCAR, winning 19 races at the Cup level and capturing championships in both the Truck Series (2000) and Busch Series (2002). He was also recognized for humanitarian work, including relief efforts in western North Carolina after Hurricane Helene.