Aviation Accident Summaries

Aviation Accident Summary ERA19FA068

Adel, GA, USA

Aircraft #1

N203SW

Saberwing Saberwing

Analysis

The airplane broke up in-flight and the wreckage was located about 6 miles southwest from the airport, scattered over a large swamp area; there were no witnesses to the accident. Examination of the airplane revealed that the wing forward spar had two significant failure areas on both the left and right wings; one was located at the side of the fuselage and one was located at the outboard wing attach points. This was indicative of shear failure of the rear spar upper attach bolts and tensile overload at the rear spar upper spar cap. The primary wing failures were due to negative overload causing failure of the upper attach points on the left and right wings. High positive loads on the horizontal stabilizers would generate downward bending loads in the fuselage that would be greatest at the rear spar location. Given these findings, it is likely that the pilot performed a pull-up maneuver aggressively or at high speed, possibly while performing aerobatics. The pull up would have generated significant down force on the tail, resulting in the left and right fuselage longerons failing in tensile overload due to the downward bending loads in the fuselage in excess of the structural capabilities of the airplane. This sudden failure would cause the airplane to pitch over violently resulting in the negative overload wing failure.

Factual Information

HISTORY OF FLIGHTOn December 18, 2018, about 1500 eastern standard time, an experimental amateur-built Azalea Saberwing, N203SW, was destroyed during an inflight breakup near Adel, Georgia. The private pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to a witness, the pilot was flying in the traffic pattern at the Cook County Airport (15J), Adel, Georgia, before departing the area to the west. Another witness, located about 6 miles west of 15J, arrived home and observed airplane parts scattered in his yard. There were no witnesses to the accident. AIRCRAFT INFORMATIONThe Azalea Saberwing was an experimental, amateur-built, single-engine, low wing, composite airplane with a conventional tail and fixed conventional landing gear. The airplane was primarily manufactured from fiberglass composite sandwich panels using woven and unidirectional fiberglass cloth with foam core that was infused with resin. The fuselage bulkheads, wing spars, and tail spars were constructed of wood. The center portion of the wing, about 7 ft long, was bonded in the lower fuselage during construction, and the outboard portions of the wings were attached through bolted fittings on the forward and aft spars. The forward and aft wing spars were a wooden box design with Sitka spruce spar caps and ribs and Birch plywood webs. AIRPORT INFORMATIONThe Azalea Saberwing was an experimental, amateur-built, single-engine, low wing, composite airplane with a conventional tail and fixed conventional landing gear. The airplane was primarily manufactured from fiberglass composite sandwich panels using woven and unidirectional fiberglass cloth with foam core that was infused with resin. The fuselage bulkheads, wing spars, and tail spars were constructed of wood. The center portion of the wing, about 7 ft long, was bonded in the lower fuselage during construction, and the outboard portions of the wings were attached through bolted fittings on the forward and aft spars. The forward and aft wing spars were a wooden box design with Sitka spruce spar caps and ribs and Birch plywood webs. WRECKAGE AND IMPACT INFORMATIONThe wreckage was located in a swampy area 6 miles southwest from 15J; the wreckage field was about 6,000 ft long by 1,000 ft wide. The fuselage fractured near the aft wing spar; additionally, the left and right outboard wings, vertical stabilizer, rudder, horizontal stabilizer, and elevator were dispersed amongst the wreckage field consistent with an inflight breakup of the airplane. At the beginning of the debris field, the vertical stabilizer was located; it was separated into 2 pieces. The next part that was located was the rudder, which was separated from the vertical stabilizer. The entire horizontal stabilizer assembly was then located, with both elevators still attached and intact. There was no damage to the aft fuselage below the tail. The left flap assembly was located next along the debris path on the left side of the debris field. The right wing assembly was located on the right side of the debris field and included the aileron, flap, and landing gear assembly. The empennage was found forward of the right wing assembly. The cockpit and engine were found near the end of the debris field. The engine remained attached to the engine mounts and attached to the firewall of the cockpit section. All three propeller blades were broken at the propeller hub. All of the propeller blades had scoring and impact marks throughout the span of the blades. The left wing was not located during the initial search but was later found on February 1, 2019, in the swamp near where the cockpit was located. Examination of the fuselage longerons that ran below the canopy revealed that they had fractured in tension overload, on both sides of the fuselage near the location of the rear spar. The tensile fractures were consistent with fuselage bending in the downward direction. MEDICAL AND PATHOLOGICAL INFORMATIONThe Division of Forensic Sciences, Georgia Bureau of Investigation, performed an autopsy on the pilot. His cause of death was multiple blunt force injuries. Toxicology testing performed at the FAA Forensic Sciences Laboratory was negative for carbon monoxide, ethanol, and drugs.

Probable Cause and Findings

The in-flight failure of the fuselage, as a result of the pilot conducting maneuvers that exceeded the structural capabilities of the airplane.

 

Source: NTSB Aviation Accident Database

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