Beechcraft 1900D Pitch Trim Cable Rupture Incident (F-GOPE)

Incident Overview and Flight Details On 9 October 2012, at approximately 07:40 UTC, a Beechcraft 1900D with registration F-GOPE, operated by Hex'air, was conducting a scheduled domestic passenger flight from Lyon Saint Exupéry to Rodez Marcillac. The flight crew consisted of a pilot-in-command, a first officer, and six passengers were on board. During the initial climb in visual meteorological conditions, the first officer observed that the electric pitch trim control was inoperative. The manual pitch trim control also failed to function. The crew stabilized the aircraft at 5,000 feet and 140 knots, decided to turn back, and maintained a speed below 140 knots until the final approach. The aircraft landed safely on runway 36L with flaps set to 35 degrees. No injuries or damage were reported. ## Technical Investigation and Findings Following the landing, the pitch trim cable was found to be broken. The cable, which is a steel loop consisting of seven strands (each with seven wires) connecting the cockpit to the elevator, was found broken at the winding around the pulleys of the autopilot servo. Half of the wires broke due to overload, while the other half broke due to fatigue crack propagation. The fatigue failure appeared to be related to the specific stresses on the cable during winding around the pulley. The material and surface treatment were found to be in accordance with the manufacturer's specifications. ## Maintenance and Similar Cases The aircraft F-GOPE had accumulated 21,144 cycles and 15,400 flight hours and was up to date with maintenance. Visual inspections, including the use of a cloth to detect broken wires, had not detected any damage to the pitch trim cable. The manufacturer does not provide for systematic or regular replacement of the cable, only when damage is observed. In September 2006, a similar pitch trim cable rupture was reported by an operator. The manufacturer issued a Safety Communique in October 2006 recommending an annual inspection of the cable at its winding in the pitch servo. This inspection was visual and mechanical. ## Conclusion and Recommendations The incident was caused by fatigue cracking of the steel wires in the pitch trim cable, which could not be detected during planned maintenance. The BEA recommended that the FAA, in coordination with the manufacturer, make mandatory a modification of the pitch trim system or, failing that, the regular replacement of the pitch trim cable to prevent undetectable fatigue rupture.