The cause of the Wright “B” Flyer crash in Green Twp. that killed two pilots last year was likely because of a failed propeller shaft weld that resulted in a loss of engine thrust, federal investigators have determined.
A post-accident examination of the Silver Bird experimental aircraft’s left propeller shaft revealed a broken weld, which would have prevented the left propeller from being driven by the engine and therefore resulted in the loss of thrust, according to a probable cause report released this week by the National Transportation Safety Board.
The July 30 crash resulted in the death of experienced volunteer pilots Don Gum, 73, of Beavercreek and Mitchell Cary, 64, of Yellow Springs. They were unable to maintain control of the aircraft after the loss of thrust, the NTSB determined.
Both pilots were certified as commercial pilots and had more than 300 hours of combined flight time in the same make and model as the crashed airplane and more than 4,030 of total flight time.
Further investigation revealed that 25 to 35 percent of the thickness of the propeller shaft tube was not welded to the propeller shaft end. The part’s engineering drawing specified complete weld penetration, according to the report.
In a report released in late October, the NTSB indicated it was investigating the propellor shaft weld.
The Wright Flyer look-alike crashed seconds before 10:45 a.m. in a field about a mile west of 7391 Pitchin Road — nearly 40 minutes into a test flight originating from Springfield-Beckley Municipal Airport.
Wright “B” Flyer Inc. President Phil Beaudoin said Thursday the nonprofit company’s management and board of directors were reviewing the probable cause report but declined further comment.
Beaudoin also declined to say where the propeller shafts were welded. He’d confirmed to the Springfield News-Sun in November that the work had been contracted out.
A high definition video camera on board showed that plane yawed near the end of the recorded video. Both pilots were observed to manipulate controls following the yaw, and it showed the plane was controllable.
Several witnesses in the area reported hearing the airplane’s engine sound as though its RPM varied and observed it to be flying slow and banking to the left and right just before the crash. One witness reported that it spiraled downward.