NTSB Identification: LAX04FA167.
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Accident occurred Thursday, March 18, 2004 in Jean, NV
Probable Cause Approval Date: 01/31/2006
Aircraft: Piper PA-38-112, registration: N2421D
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The airplane impacted flat desert terrain following an in-flight loss of control. There were no witnesses to the accident. The local solo instructional flight departed about 45 minutes prior to the accident. Recorded radar data indicated that the airplane flew on a southerly course and conducted numerous aerial maneuvers consistent with the type normally practiced during primary flight training. Following the maneuvers, the airplane landed at a nearby uncontrolled airport, then departed again in a northeast direction for 3.8 nm until radar contact was lost. The last radar contact was about 800 feet laterally west of initial impact point, at an above ground altitude of 2,400 feet. The airplane impacted the ground in a steep left bank with a nose low attitude around 30 degrees. The debris field was approximately 100 feet in length, with an energy path opposite in direction to the flight track shown by the recorded radar data. All flight control surfaces were located within the immediate area of the accident site. The right wing separated from the fuselage and was located 30 feet from the fuselage. The right wing aileron balance cable exhibited a tension overload failure inside the right wing. The right wing primary aileron cable was found disconnected at the turnbuckle where it attaches to its corresponding rod end clevis fitting located in the fuselage. The turnbuckle barrel remained attached to the primary cable assembly and the clevis fitting remained attached to the link assembly. The turnbuckle barrel was safety wired on the outboard half that attaches to the primary cable and the safety wire looped back onto itself locking the turnbuckle barrel to the cable. No safety wire or locking device was found on the inboard half of the turnbuckle barrel or clevis fitting. Visual inspection of the threads of both the turnbuckle barrel and the clevis end disclosed that they were undamaged. According to the Piper PA-38-112 parts catalog, the primary cable turnbuckle barrel is to be secured with NAS651-16S locking clips on both sides; however, no clips were found at the accident site or during the subsequent detailed inspection of the wreckage. With the particular configuration of the turnbuckle assembly, it could not be properly secured by the use of safety wire alone. Measurement of the primary right wing aileron cable found that it was not stretched and there was no evidence to indicate that it was connected during the impact sequence. Aircraft records indicated the aileron flight control cable system, including the primary right wing aileron turnbuckle area, were visually inspected at the last 100-hour inspection. The aircraft maintenance records did not have any entries involving the adjustment, removal, or replacement of the aileron flight control cables or components, and the investigation was unable to establish when the safety wire was substituted for the NAS651-16S clips. The three pilots who had flown the airplane on the day before the accident (including one instructional flight and a private pilot practical flight test) reported that there were no discrepancies with the airplane during the flights. The physical evidence is wholly consistent with the primary aileron cable turnbuckle not being connected at ground impact. It is unlikely that the departure from controlled flight that resulted in the ground collision was due to the disconnected aileron cable; however, such a disconnect clearly could hinder any upset recovery effort. Visual meteorological conditions prevailed with no evidence of unusual, hazardous, or violent weather in the area. Evidence clearly shows the engine was producing significant power at ground impact.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The student pilot's failure to regain control of the aircraft following an upset due to the disconnected primary right aileron control cable. The failure of the company maintenance personnel to detect and correct the improperly secured turnbuckle fitting at the last 100-hour inspection is also causal. Full narrative available
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