The ATP-rated pilot, who had logged 19,275 hours, including 178 in the Skybolt, an aerobatic biplane, decided to do some low altitude aerobatic maneuvers near Windsor, N.C.
After takeoff, he did two fly-bys along the runway, then pulled up to between 300 and 500 feet AGL and performed a wingover maneuver, although federal regulations prohibit aerobatic maneuvers below 1,500 feel AGL.
According to the pilot, at the bottom of the wingover, he noticed that the engine did not respond when he advanced the throttle and the rpm was decreasing. The airplane came down hard in a field.
The crush and compression damage to the lower left wing was consistent with the airplane incurring a high-G impact.
The NTSB determined the probable cause as the pilot’s decision to initiate an aerobatic maneuver with insufficient altitude to recover before ground impact.
NTSB Identification: ERA13LA238
This May 2013 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.
As a 35 year aircraft mech, whenever I hear the words ” temporary loss of power”, my go -to items are filters and fuel vent system.
Engine performance or lack thereof on recovery from a wingover at any altitude has little if anything to do with aerodynamic performance in recovering from the ensuing round out at the bottom of the maneuver though prop wash along the wing roots caused by moderate to high rpm engine power will aid in reducing the tendency for an accelerated stall. My guess is the surprise panic of what was likely a temporary loss of power that may have been due to unporting a fuel supply source at the top of the wingover sufficiently interrupted the pilot’s attention in applying the needed pitch control (relaxed stick back pressure) which caused the airplane to round out too low at the bottom of the recovery. Obedience to the regs would have prevented the mishap.
According to the linked NTSB report the aircraft engine and fuel delivery systems were all “go” following the crash, so what actually happened? Would, for example, an “uncoordinated” wingover perhaps unport the fuel tank pickup points causing a momentary starvation/loss of power situation?
Any Skybolt drivers (or constructors) out there?
The Steen Skybolt is a tandem two-seat amateur built biplane of welded chrome-molybdenum steel tube fuselage and tail unit, fabric covered, with braced wings of wooden construction, fabric covered. Design billed as “fully aerobatic”. Usual engine is a Lycoming 180 Hp but has design provision for alternative engines of 125-300 Hp. Stressed to +12 & -10 g.
Low level maneuvering pilot error below the FAA minimum bit this one hard.