North Pole, AK, USA
N3050B
Cessna 195B
The commercial certificated pilot was landing a tailwheel-equipped airplane on a gravel surface runway. During the landing roll, with about 35 knots of airspeed, the airplane began to drift to the right. The pilot said he applied left brake pressure, but the pedal went to the floor without producing any braking action from the left brake. The airplane departed off the right side of the runway and ground looped to the right. The left main gear strut fractured, just outboard from the fuselage, and the left wing struck the ground. The airplane received damage to the fuselage and the left wing. An FAA inspector examined the airplane at the accident site, and reported that the actuator rod, connecting the left brake pedal to the left brake master cylinder, was fractured. The point of separation had flat fracture planes oriented 90 degrees to the long axis of the rod. The FAA inspector also examined and photographed the separated left main landing gear strut. The point of separation was oriented perpendicular to the span of the gear strut. Visual examination of the fracture surface of the gear strut revealed flat fracture planes with multiple beach marks radiating in successive arc patterns from the outer edges of the strut. The landing gear on the accident airplane is a spring steel strut that is bolted to the fuselage at its upper end. Neither the manufacturer nor the FAA, have established a life limit (hours or cycles) for the main landing gear strut. No inspection procedures, other than a general visual inspection of the landing gear, have been specified by the manufacturer or the FAA.
On October 16, 2003, about 1745 Alaska daylight time, a wheel-equipped Cessna 195B airplane, N3050B, sustained substantial damage when the left main landing gear collapsed following a loss of control during the landing roll at Bradley Sky-Ranch Airport, North Pole, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The commercial certificated pilot, and the sole passenger, were not injured. Visual meteorological conditions prevailed. No flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on October 16, the pilot reported that he landed on runway 33 at Bradley Sky-Ranch in wind conditions that were light and variable. During the landing roll, with about 35 knots of airspeed, the airplane began to drift to the right. The pilot said he applied left brake pressure, but the pedal went to the floor without producing any braking action from the left brake. The airplane departed off the right side of the gravel surface runway and ground looped to the right. The left main landing gear strut fractured, just outboard from the fuselage, and the left wing struck the ground. The airplane received damage to the fuselage and the left wing. A Federal Aviation Administration (FAA) aviation safety inspector, Fairbanks Flight Standards District Office (FSDO), examined the airplane at the accident site. The inspector reported that the actuator rod/shaft, connecting the left brake pedal to the left brake master cylinder piston, was fractured. The actuator rod has several circumferential grooves machined along the axis of the shaft. The point of separation, at one of the grooves, had flat fracture planes oriented 90 degrees to the long axis of the rod. The FAA inspector also examined and photographed the separated left main landing gear strut. The point of separation was perpendicular to the span of the gear strut. The fracture surface had flat fracture planes with multiple beach marks radiating in successive arc patterns from the outer edges of the strut. The landing gear on the accident airplane is a spring steel strut that is shot peened during manufacture, and is bolted to the fuselage at its upper end. It is braced by a fuselage support bracket at the outer edge of the fuselage. Visual inspection of the landing gear strut is required at prescribed intervals by 14 CFR Part 43. Removal of the gear for visual inspection, or the use of nondestructive inspection techniques (NDT), is not required. Neither the manufacturer nor the FAA, have established a life limit (hours or cycles) for the main landing gear strut. The Safety Board issued Safety Recommendations A-01-01 and A-01-02 on March 16, 2001, that recommended the FAA issue airworthiness directives (AD) for initial and repetitive inspection of tailwheel-equipped Cessna 170, 180, 185, 190, and 195 series airplanes main landing gear spring struts. The Safety Board noted that Cessna tailwheel-equipped airplanes, and Cessna nose wheel-equipped airplanes, have main landing gear spring struts of similar design, but also indicated that there were only 5 reports of nose wheel-equipped main landing gear fatigue failures. On August 31, 2001, the FAA disagreed with the Safety Board's recommendation, and indicated that not enough evidence was found to support an AD. The FAA indicated that the Cessna Maintenance Manual specified inspections of the landing gear every 50 hours and during annual inspections, and that these inspections were adequate to detect cracks in the main landing gear struts and additional action was not warranted. The FAA also indicated that a General Aviation Alert in Advisory Circular 43-16A (August 2001) was published to reiterate that visual inspections of the spring strut should be performed every 50 hours, and during annual inspections as required by the Cessna maintenance manuals. On March 25, 2002, the NTSB responded to the FAA by stating, in part: "The Safety Board continues to believe that a visual inspection alone will not detect cracks in the Cessna main landing gear spring struts. However, the Safety Board acknowledges that the statistical evidence does not warrant issuance of ADs at this time as called for in the Board's recommendation." The Safety Board subsequently classified Safety Recommendations A-01-01 and A-01-02 as "Closed, Reconsidered."
A fracture of the left brake master cylinder actuator rod, which resulted in failure of the left brake, a loss of directional control and an inadvertent ground loop during landing, and the separation of the left main landing gear strut due to fatigue. Factors contributing to the accident were the manufacturer's and the FAA's insufficient standards/requirements for inspection procedures of spring steel landing gear struts.
Source: NTSB Aviation Accident Database
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