IAD99LA045

The airplane was landing in turbulent wind conditions, at a 3,792-foot elevation airport, with winds from 40 degrees to the right, at 26, gusting to 31 knots. The airplane touched down left of runway centerline, approximately 3,100 feet from the beginning of the 5,601-foot runway. The left main landing gear folded, and the airplane bounced. It then touched down on the right main landing gear, about 200 feet further down the runway. It then settled on the left propeller and fuselage about the 2,000 feet-remaining marker, and skidded an additional 1,100 feet. Post-flight examination revealed that the left main landing gear inboard retract cylinder clevis was fractured approximately 1 1/8 inches below the attaching bolt hole. Additionally, a crack at the center of the upper drag brace was found in the webbing where the landing gear door actuating mechanism attached. Laboratory examination of the fracture in the retract cylinder clevis revealed features typical of a bending overstress separation. Laboratory examination of the upper drag brace crack revealed small fatigue crack regions on both sides of a manufactured hole, with no evidence of preexisting mechanical damage, or other defects in the hole. Remaining portions of the crack in the upper drag brace were consistent with overstress.

On May 24, 1999, about 1055 eastern daylight time, a Gulfstream American 690C, N840V, was substantially damaged when the left main landing gear collapsed during a landing at Ingalls Field (HSP), Hot Springs, Virginia. The certificated commercial pilot and two passengers were not injured. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed for the business flight conducted under 14 CFR Part 91. The flight originated from the Blue Grass Airport (LEX), Lexington, Kentucky, about 0945.

The pilot stated that the en route portion of the flight was uneventful. Approaching HSP, he canceled the IFR clearance, requested airport advisories, and entered the airport traffic pattern on a left base leg for Runway 24. Wind conditions were turbulent, so he increased approach airspeed by 5 knots, to 105 knots. The pilot made a "normal touchdown, not particularly hard, within the first third of the runway and on the right main landing gear." He remembered that the left main landing gear had touched down, and the airplane had rolled about 100 feet, when the left main landing gear collapsed. The airplane skidded to the left and came to rest in an upright position, partially off the runway.

According to witness statements, the airplane touched down on the left main landing gear first. One witness saw smoke at that time, and saw the landing gear immediately collapse. Witnesses noted that the airplane then bounced, touched down on the right main landing gear, and finally settled down on the left propeller and fuselage.

Winds recorded at the airport, 4 minutes after the accident, were from 280 degrees magnetic, at 26, gusting to 31 knots.

By the time a Federal Aviation Administration (FAA) Inspector arrived, on May 25, 1999, the airplane had been moved to a hangar apron. The Inspector noted that skid marks on the 5,601-foot runway commenced approximately 3,100 feet from the beginning of the runway, left of centerline. About 200 feet further along, there was a skid mark that correlated to the right main landing gear, and about 300 feet beyond that, skid marks correlated to the left propeller and fuselage. The marks continued an additional 1,100 feet, and ended just past the 1,000-foot remaining marker.

Examination of the airplane revealed that the left main landing gear inboard retract cylinder clevis was fractured, approximately 1 1/8 inches below the attaching bolt hole. A crack was also found at the center of the upper drag brace, in the webbing where the landing gear door actuating mechanism was attached.

The upper drag brace and the clevis were removed from the airplane, and sent to the Safety Board Materials Laboratory for further examination. According to the metallurgist's factual report, the crack at the center of the upper drag brace progressed through a manufactured hole. There were small fatigue crack regions on both sides of the hole, with crack initiation from multiple locations within the hole. "There was no evidence of preexisting mechanical damage, or other defects in the hole. Remaining portions of the crack in the upper drag brace were consistent with overstress."

"Examination of the fracture in the retract cylinder clevis...revealed features typical of a bending overstress separation."

According to the Airport/Facility Directory, the airport elevation was 3,792 feet.

The pilot reported that he had approximately 12,300 hours of flight time, with 900 hours in make and model.