Aviation Accident Summaries

Aviation Accident Summary MIA02LA042

Newnan, GA, USA

Aircraft #1

N6129F

Ferguson A 26 Vulcan SS

Analysis

According to eyewitnesses to the landing, the twin Rotax powered, pusher configured, 2-place light experimental aircraft's landing touchdown occurred about 130 feet down the 600-foot private grass runway. After touchdown, the left wing dropped, and a small puff of dust was observed under the left wing as in something dragging concurrently with commencement of a left drift. A go around attempt was heard and observed, and the left wing collided with a fence pole on the left runway edge at about 336 feet down the runway. Following the fence pole collision, the aircraft continued left until small tree collision with the right wing caused a right yaw and a secondary severe, sideward collision between a large tree and the cockpit left side. The day before, the pilot experienced a similar loss of runway directional control and, via an e-mail to a friend following the occurrence, attributed it to either not having both main landing gear firmly on the runway before application of wheel braking, or the difference in wheel-to-surface friction properties while braking. Postcrash examination of the main wheel brakes revealed no locked up condition.

Factual Information

On December 7, 2001, about 1630 eastern standard time, an experimental Ferguson A-26 Vulcan SS, N6129F, registered to a private individual, operating as a Title 14 CFR Part 91 personal flight, crashed while attempting a go-around from a private strip in the vicinity of Newnan, Georgia. Visual meteorological conditions prevailed and no flight plan was filed. The homebuilt-kit aircraft received substantial damage, the airline transport-rated pilot sustained fatal injuries, and a passenger sustained serious injuries. The flight departed the same airstrip about 30 minutes before the accident. According to the pilot's wife and son, the pilot flew N6129F to Spectrum Aircraft Corporation, the U.S. distributor for the Vulcan line of homebuilt kits, located at Sebring, Florida, for the purpose of performing 150-hour inspections on the Rotax 582-UL-DCDI-99 engines, as well as an annual inspection on the airframe, on October 23, 2001. Additionally, the aircraft was to have a transponder and an angle of attack indicating system installed. In early December 2001, the pilot returned to Sebring, and flew the aircraft back to his home field. The engines had been inspected, however, the angle of attack system had not been calibrated, and the airframe's annual inspection had not been completed. The pilot completed the annual inspection himself, upon his return home on December 5, 2001. According to a neighbor pilot who flew with the accident pilot the day before the accident, they performed 11 landings at five different grass airstrips that day. On the 10th landing, as they were returning the neighbor to his own airstrip, the accident pilot lost directional control during landing rollout, and the aircraft took an excursion off the left side of the runway before it was brought under control. The neighbor pilot stated he thought the tracking problem was the single lever design of the main wheel brakes. He stated it was easy to lock one side of the main wheel brakes on grass or dirt runways, causing a slide with a resultant loss of directional control. The problem could occur on application of brakes, or conversely, on releasing of brakes. On sod or dirt surfaced runways, differential braking is preferred. He stated he had experienced the same braking system problems on a previous homebuilt of his own. He stated that postcrash, both main gear wheels spun freely, and exhibited no brake lockup. He added that a factor in the severity of the pilot's injuries was the lightness of the mounting of the shoulder harness for the front seat. According to a friend of the pilot, an FAA certified mechanic, and an eyewitness to the accident, he had flown twice with the pilot/owner on the day of the accident, and his wife was in the back seat at the time of the accident. He and the pilot/owner had discussed installing individual toe brakes on the aircraft to improve directional control on the runway during braking. He and the pilot/owner's wife watched the accident from a vantage point where the aircraft was landing away from their location. After touchdown, he saw the left wing drop and a dirt cloud under the left wing as if either the left wing struck the terrain, and/or the left brake was dragging or locked. He saw the aircraft drift left of runway centerline, and then he heard the engines powering up. The aircraft became airborne, but the left wing hit a left edge fence post, and the aircraft impacted the trees. The right wing impacted two pine trees and yawed the aircraft clockwise causing the major collision between the left side fuselage, (abeam a point between the pilot's knees and hip) and a 5- to 6-inch diameter hardwood tree at a point about 5 feet agl. The aluminum tubing cross member behind the pilot's seat that forms the forward seat's upper shoulder harness attachment is anchored to two round sockets bolted to the cockpit sidewall under the longeron that serves as the cockpit coaming on each side of the aircraft. The inner diameter of the 3/4-inch deep anchoring sockets match the outer diameter of the cross member which is fitted into the sockets with small aluminum rivets. In the collision sequence, the left side fuselage revealed evidence of heavy side loading, and those rivets sheared, causing sideward separation of the cross member from its anchoring socket, resulting in the pilot's body restraint effectiveness being compromised. The mechanic forwarded to the NTSB an email sent to him the day before the accident by N6129F's pilot/owner relating to the landing excursion incident mentioned in a previous paragraph. In the accident pilot's own words, he states the importance of ensuring that both main wheels are firmly on the ground before wheel braking is commenced. Additionally, he emphasized the desirability of being able to differential brake on landing surfaces with varying frictional properties, as in wet grass and dry grass. The email is an attachment to this report. As to the suggestion that the accident may have been caused by asymmetrical powering up of the engines during the go around, the mechanic stated that the pilot was so proud of the airplane's takeoff and climb performance due to excess power that he liked to demonstrate single engine takeoffs. His assessment was that the pilot could maintain airborne directional control with any combination of power output from the twin engines. According to an FAA inspector, examination of the accident site and markings on the runway revealed the aircraft dragged the left wing after landing, and the go-around attempt resulted in an excursion off the left runway edge, into an adjacent metal fence post and trees. The airstrip is reported to be about 600 feet long, oriented in a northeast/southwest direction. Marks on the runway revealed the aircraft touched down at about the 130-foot mark, dragged the left wing for about 50 feet that caused about a 25 degree left directional drift, attempted a go around and became airborne, collided with a fence post at about the 264-foot mark with the left wing, and crashed into hardwood trees abeam of the 400-foot mark, at about 40 feet left of the runway's left edge. The inspector found no discrepancy with the tail wheel. No autopsy was performed on the pilot. The coroner's report stated that the cause of death to the pilot was, "cardio-respiratory arrest" and "second degree basilar skull fracture secondary to a plane crash." Toxicological testing was not requested by the FAA.

Probable Cause and Findings

The pilot's failure to maintain directional control during landing and go-around, resulting in a collision with a runway perimeter fence pole and trees.

 

Source: NTSB Aviation Accident Database

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