NTSB Identification: LAX04LA194.
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Accident occurred Saturday, April 17, 2004 in PAGE, AZ
Probable Cause Approval Date: 05/30/2006
Aircraft: Cessna 205, registration: N1815Z
Injuries: 2 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The airplane landed hard after the pilot's control wheel fractured and separated in the landing flare. The pilot said that as he was adding back pressure to flare the airplane his control wheel fractured and separated at the upper left corner. The airplane's nose dropped rapidly and impacted the runway surface first, resulting in the airplane bouncing back into the air. The pilot repositioned his hand behind the broken wheel to the control column and manipulated the broken control yoke forward in an effort to maneuver the airplane back down to the runway surface; the nose landing gear bent and the propeller impacted the runway. The airplane was manufactured in 1962 and equipped with a polymeric control wheel. A metallurgical examination of the fracture surface on the control wheel revealed smooth crack arrest markings along with bands of slightly different colors, indicative of fatigue cracking. The location of the fracture indicated that the fatigue crack propagated as a result of tensile stress from the continual force of the pilot manipulating the control wheel forward and aft. The discoloration and crazing gave evidence of aging effects. The fatigue cracks likely initiated from age related crazed cracks in an area of maximum tensile stresses. The dirt and discoloration of the fracture (and the adjacent cracks and/or crazes), along with the depth of the fatigue crack would suggest that the crack has been in existence for a relatively long time (years, perhaps). Although the fatigue crack would not have been visible from the pilot's viewpoint, it occurred in an area where cracking would be most likely to occur based on the geometry of the yoke. The airplane underwent its last annual inspection 17.76 hours prior to the accident. The airplane manufacturer issued a Service Letter in1964 requiring a one time inspection and proof testing of applicable control wheels. The Service Letter further stated that once control wheels were checked, no further control wheel inspection was required. To show compliance with the Service Letter, a red dot was to be placed on the forward rivet butt on the bottom of the yoke. Both control wheels installed on the accident airplane showed evidence of a red material within the forward rivet butt, indicating that the inspections dictated by the Service Letter were previously preformed. The Federal Aviation Administration issued a Special Airworthiness Information Bulletin (SAIB) in 2001 recommending that during periodic (100-hour or annual) inspections "special emphasis" should be placed on the original plastic control wheels installed in applicable airplanes. If crack indications were "unclear," it recommended that a test be performed in accordance with the manufacturer's Service Letter. The SAIB does not provide a specific location or guidance as to the visual indicators where the cracks are likely to propagate. A review of the Service Difficulty Report (SDR) database revealed a history of 18 control wheel failures in the applicable airplanes, of which a majority reported failures that occurred during a critical phase of flight, including: takeoff, initial climb, spin recovery, and landing flare. Five of the reported failures occurred after the issuance of the SAIB.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the fatigue fracture and separation of the pilot's control wheel, which resulted in a momentary loss of control and a hard landing. Full narrative available
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