What happened
On February 2, 2000, a VFR navigation training flight departed from Hoogeveen airport. During the initial climb to approximately 200 feet, the instructor noticed the student pilot was holding the control wheel in an unusual position. Upon taking control of the aircraft, the instructor discovered that the ailerons were not functioning correctly. Despite the loss of lateral control, the instructor managed to perform a successful landing back at the airport without using the ailerons. The aircraft, a Reims F172N with registration PH-JPO, sustained no damage, and all three occupants remained uninjured.
The investigation
The investigation focused on the mechanical state of the aileron control system. Prior to the flight, both the preflight inspection and the before-take-off checklist indicated that the flight controls were moving freely and correctly. However, post-incident examination revealed that the cable responsible for operating the left aileron had snapped.
Investigators traced the issue back to a wing repair performed in June 1998, which involved replacing the left wing. The investigation examined the maintenance history, noting that since that repair, the aircraft had completed approximately 750 flight hours and undergone twelve inspections, including three 200-hour periodic checks. While the maintenance technician noted that inspecting the cable guide roller is difficult due to the lack of a direct inspection hatch, investigators determined that the components could be adequately inspected using a flashlight and a mirror through a floor inspection port.
Findings
- The aileron control failure was caused by a broken cable.
- The breakage resulted from improper installation of the cable following a wing replacement.
- The cable was not routed correctly over the guide roller and was instead running outside of a safety bracket, causing wear and subsequent fatigue.
- This installation error went undetected during at least three separate 200-hour maintenance inspections.
- The instructor's decisive actions prevented the serious incident from escalating into a fatal accident.