Aviation Accident Summaries

Aviation Accident Summary NYC99FA097

EASTFORD, CT, USA

Aircraft #1

N56RA

Ives SONERAI II-L

Analysis

After having breakfast with a friend, the pilot departed. No one else reported seeing him or the airplane until a witness, approximately 50 yards from the accident site, saw the airplane a little over tree top level. While staying in the vicinity of the accident site, the airplane conducted several aerobatic maneuvers. Then, while in a steep turn to the left, the right wing separated, and then the left. The engine continued to run until ground impact. Examination of fractures surfaces on the spar-box revealed cold welds, and corrosion.

Factual Information

HISTORY OF FLIGHT On April 25, 1999, about 1300 eastern daylight time, a homebuilt Sonerai II-L, N56RA, was destroyed after an in-flight breakup and subsequent collision with terrain near Eastford, Connecticut. The certificated private pilot was fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under 14 CFR Part 91, that departed Fitchburg Municipal Airport, Fitchburg, Massachusetts, about 1230. A witness saw the pilot at Windom Airport, Willimatic, Connecticut, about 0900, getting ready to mount the wings on his airplane. He walked up to the accident pilot, and they had a general conversation for a couple of minutes. During the conversation the accident pilot stated he would be conducting some high altitude, true airspeed tests that day. The witness then went to an Experimental Aircraft Owner Association breakfast meeting, while the accident pilot boarded his airplane, taxied to runway 27, and departed. Approximately 1 hour later, the witness returned to the airport and saw the accident airplane parked by the fuel pumps. After watching the accident pilot taxi his airplane back to his trailer, the two men had a second conversation. During the short conversation they decided to fly to Fitchburg for breakfast. Both the witness and the accident pilot departed in two separate airplanes, and conducted separate flights to the destination. They both arrived at Fitchburg about 1130, and proceeded to have breakfast at a local restaurant. After breakfast, the accident pilot stated he was going to fly to Orange, Massachusetts to check on the status of a recently completed experimental homebuilt. The two men parted company, and the accident pilot departed Fitchburg via runway 32. There was no further reported contact with the accident pilot after that point. A witness working in his yard, approximately 50 yards from the accident site, stated that he saw the airplane coming towards him "a little over tree length." The airplane then started to do "some tricks." The airplane did about 10 "tricks", consisting of "sharp turns so that the wing's of the plane were straight up and down," and "a roll to the right." During the final maneuver the witness saw the airplane turn "quickly to the left." "As the airplane went left, the right wing which was up in the air came flying off. Seconds later, the left wing also came off." Another witness added that "...the engine ran up to the crash. The engine did not sound abnormal." The accident happened during the hours of daylight. The wreckage was located 41 degrees, 53.71 minutes north latitude, 72 degrees, 3.55 minutes west longitude, at an elevation of approximately 735 feet. PERSONNEL INFORMATION The pilot held a private pilot certificate with a single engine land rating. His last third class medical was dated June 1997. A review of the pilot's logbook revealed as of March 1999, he had logged approximately 1,348 hours of flight experience. No entry was found in the pilot's logbook for a biennial flight review in the 2 years prior to the accident. WRECKAGE AND IMPACT INFORMATION The accident site was divided into three locations, right wing, left wing, and main wreckage. The right wing marked the start of the debris path and was located approximately 370 feet south of the main wreckage. The left wing was located approximately 200 feet south of the main wreckage. The main wreckage, which consisted of the empennage, cockpit, and engine area, was located in a grassy field approximately 50 feet to the west of a residential street. The only visible damage to the top of the right wing was a compression wrinkle that started on the aileron, 3 feet outboard of the wing root, and ended at the wing root, 1 foot 4 inches aft of the leading edge. Visible damage to the bottom of the right wing was isolated to two areas. The first area was located 3 inches outboard of the wing root and on the undersurface of the leading edge. The damage in this area was consistent with compression, and had a surface area of approximately 25 square inches. The second area was located at the wing root and on the trailing edge. The damage in this area was consistent with impact, and occupied and area of approximately 15 square inches. Damage to the top of the left wing was isolated to the four corners of the wing. The first area was on the leading edge at the wing root. This area was comprised of damage consistent with impact, and had a surface area of 255 square inches. The second area was also on the leading edge but located at the wingtip. In this area, the sheet metal that comprised the wingtip was separated from the leading edge to a point 1 foot 6 inches aft. The third area was located at the wing tip's trailing edge. This damage was consistent with impact and occupied an area of approximately 80 square inches. Within this same area, the outboard tip of the aileron was bent down approximately 2 inches. The third and final area was located at the wing root's trailing edge, and consisted of small dents that covered an area of approximately 25 square inches. The horizontal stabilizer and elevator showed no visible signs of damage. The vertical stabilizer's top 4 inches were bent to the right 20 degrees, and the rudder was undamaged. The structure from the empennage to the fire wall was present, but damage consistent with impact, compression, and torsion made identification difficult. The main landing gear was attached to the fuselage just aft of the firewall, and the firewall with engine, formed the last major piece of the wreckage. The wooden propeller had separated from the engine. The carburetor separated from the engine 1/4 of an inch upstream of the throttle plate. The front two cylinders were bent aft, and dirt was imbedded in their cooling fins. Both the left and right magnetos separated from the accessory gear box. The starter, and ring gear had also separated from the engine. The spar box and associated fracture surfaces for both wings were examined at the accident site. Welds on the spar box were consistent with gas welding, and approximately 2 1/2 inches of welds were consistent with a cold weld. The spar box was fractured and separated into approximately two equal pieces. One piece remained attached to the left wing's spar, and the other to the right wing's spar. On the left top portion of the spar box, a fracture surface that originated at a weld joint displayed signs consistent with a cold weld. Also this fracture surface displayed an orange substance consistent with rust. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was preformed on the pilot, April 26, 1999, at the Medical Examiners Office in Hartford, Connecticut. ADDITIONAL INFORMATION On April 26, 1999 the wreckage was released to the owners representative who was not available to sign the wreckage release form.

Probable Cause and Findings

Inadequate welding of the airplane's spar-box by the owner/builder, which resulted in a total spar-box failure in-flight. A factor in the accident was the pilot's decision to perform aerobatics.

 

Source: NTSB Aviation Accident Database

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