Cleveland, OH, USA
N200NG
Beech A200
After takeoff, the right main landing gear would not retract. The crew attempted to troubleshoot the malfunction and tried to hand-pump the landing gear down, but were not successful. The captain made a landing to test the landing gear, but when it wouldn't hold, he aborted the landing. The captain made a subsequent landing and shut down the engines. As the airplane decelerated through 80 knots, the right main landing gear collapsed. After the accident, the airplane was placed on jacks, and when the gear handle was placed in either the up or down position, the landing gear motor rotated the torque tubes out to both main landing gear actuators, but the right main landing gear would not extend or retract. The right main landing gear actuator was forwarded to the airplane manufacturer for further examination. According to a company metallurgist's report, there was a fracture of the actuator housing inboard pivot hub flange, and a fracture through the shaft section of the pinion gear. Examination of internal components revealed fractures to most of the ring gear teeth, and a segment of metal was separated from a pinion gear tooth. Microscopic examination of ring gear fracture surfaces revealed arrest lines, "representative of progressive fracture." Metalographic examination of a polished and etched cross section of gear tooth revealed crack arrest lines, "again indicating cyclic progression of crack growth." Microscopic examination of ring gear tooth profile surfaces revealed "excessive polishing of the tooth faces, together with rounding of the tooth corners...typically representative of high tooth loads created by inadequate operating clearance between the ring gear and pinion gear."
On October 9, 2002, at 1518 eastern daylight time, a Beech A200, N200NG, operated by the Jacksonville, Florida, Sheriff's Department, was substantially damaged during an emergency landing shortly after takeoff from Burke Lakefront Airport (BKL), Cleveland, Ohio. The two certificated airline transport pilots and one passenger were not injured, and another passenger sustained minor injuries. Visual meteorological conditions prevailed. The airplane was initially operating on an instrument flight rules (IFR) flight plan, to Craig Municipal Airport (CRG), Jacksonville, Florida. The public use prisoner transport flight was conducted under 14 CFR Part 91. According to the captain, after takeoff, as the first officer moved the landing gear selector to the 'Up' position, tower personnel advised the crew that there was a "noticeable right gear extension." The first officer also announced an unsafe gear condition on the right main landing gear, and confirmed the unsafe gear condition visually. The crew maneuvered the airplane over Lake Erie, attempted to troubleshoot the landing gear malfunction per the manufacturer's Pilot's Operating Manual, including trying to hand-pump the landing gear into position, but were not successful. The captain then notified the tower controller that they would be making an emergency landing. Tower personnel confirmed the readiness of crash-fire-rescue services, and the availability of local law enforcement. The prisoner was released from his restraints, and the crew briefed emergency landing and egress procedures to the passengers. The captain flew the airplane past the tower, and the controller again confirmed an unsafe right main landing gear. The captain then made a landing, to a "soft touch...to test the partial down position of the right main gear," and determined that the landing gear was not sufficiently extended to avoid a propeller strike. The captain then aborted the landing. During the subsequent flight around the traffic pattern, the crew decided to land the airplane on the nose landing gear and left main landing gear, shut down both engines, and feather the right engine. The captain then landed the airplane, and as it decelerated through 80 knots, the right main landing gear collapsed, and the right propeller and right wing flap struck the runway. The airplane departed the right side of the runway, and struck runway marker lights and Visual Approach Slope Indicator (VASI) system lighting before coming to a stop. After the accident, the airplane was moved from the site, placed on jacks, and examined under the supervision of Federal Aviation Administration (FAA) inspectors. According to a written statement signed by both inspectors, the landing gear handle was placed in the up position and the nose landing gear and left main landing gear fully retracted. The right main landing gear did not move. When the landing gear handle was placed in either the up or down position, the landing gear motor rotated the torque tubes out to both main landing gear actuators, but only the left gear extended and retracted. The right main landing gear actuator was subsequently forwarded to Raytheon Aircraft Company for further examination. According to a company metallurgist's report, reviewed by a Safety Board metallurgist, an initial examination revealed a fracture of the actuator housing inboard pivot hub flange, and a fracture through the shaft section of the pinion gear. Examination of internal components revealed fractures to most of the ring gear teeth, and a segment of metal was separated from a pinion gear tooth. The separated segments of fractured teeth were intermixed with lubricating grease. Microscopic examination of ring gear fracture surfaces revealed arrest lines, "representative of progressive fracture." Metalographic examination of a polished and etched cross section of gear tooth revealed crack arrest lines, "again indicating cyclic progression of crack growth." Microscopic examination of ring gear tooth profile surfaces revealed "excessive polishing of the tooth faces, together with rounding of the tooth corners...typically representative of high tooth loads created by inadequate operating clearance between the ring gear and pinion gear." Hardness testing of a gear tooth resulted in a tensile strength result consistent with that required. The pinion gear shaft was separated from the base of the gear section. There was a polished appearance on the shaft fracture face which obliterated key topographical features, "and indicated rotation of the fractured shaft against a stationary pinion section of the gear as rotational motion was applied to the separated shaft section by the actuator drive system." At the center of the shaft cross section, there was "dimple rupture representative of overload." Examination of the fracture surface where the segment of pinion gear tooth had separated did not reveal any crack lines. The separation, which "appeared to be a secondary fracture, resulted from overload such as might result from contact with a segment of ring tooth gear that had been trapped...." According to maintenance records, the left and right main landing gear had been manufactured by Raytheon Aerospace, and installed at Raytheon Aerospace on February 12, 1996. No further maintenance, other than standard phase maintenance, had been performed on the landing gear. There were approximately 1,060 cycles on the airplane since the landing gear installation.
Inadequate operating clearance between the ring gear and pinion gear during the manufacturing process resulting in the failure of the landing gear actuator gear ring.
Source: NTSB Aviation Accident Database
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