NYC05FA006 · Beech H50

The airplane had not been flown for about 5 years prior to the accident, and was undergoing maintenance in preparation of a ferry flight. A mechanic reported that he had asked the pilot to conduct some engine run-ups as close to full power as possible. The pilot taxied to runway 35, a 2,470 foot-long, 35 foot-wide, gravel and turf runway; where he performed two high speed engine run-ups. The mechanic thought that the pilot was going to perform another run-up, when the airplane accelerated, and lifted off the runway. He noted that it appeared that the pilot departed with full flaps, or at least "more than 10 degrees." The airplane began to climb momentarily, before it rolled left about 90 degrees and descended. The airplane's outboard left wing contacted the ground first, before the remainder of the airplane impacted in a nose down position, about 400 feet to the west of the departure end of the runway. Examination of the airplane did not reveal any mechanical malfunctions. Flap actuator measurements of the inboard and outboard, right and left flap actuator rods corresponded with a flap extension of 30 degrees. The airplane flight manual (AFM) procedure for "minimum run" and "obstacle takeoffs" was to utilize a 20-degree flap setting. With regards to conducting a go-around, with the flaps fully extended, the AFM stated to retract the flaps immediately to the 20-degree position. The AFM further indicated that most of the lift gained by lowering the flaps was found in the first 20 degrees of travel. The last 10 degrees provided some lift, but caused much drag..." The weather reported at an airport located about 10 miles southeast of the accident site, included clear skies, and winds from 230 degrees at 9 knots, with gusts to 19 knots.

Verbatim NTSB analysis and probable cause from the NTSB dataset