In this image from the FAA, the arrow shows the correct presence of safety wire securing the bolt head. On the accident SR20, the bolt was missing, presumably from breakage of the safety wire or the failure of maintenance personnel to reinstall it after maintenance.
The FAA issued an Aviation Maintenance Alert this week pertaining to Cirrus SR20 and SR22 aircraft. It calls for closer visual inspection of the safety wire securing the bolt between the roll actuator and the aileron itself. The head of the bolt and the safety wire are visible during the walk-around inspection.
The recommendation comes after the May 2018 crash of an SR20 in Houston. The pilot reported loss of roll control immediately after takeoff, but was able to land straight ahead just beyond the departure end of the runway. According to the FAA, “Examination of the airplane after the accident revealed that the left aileron actuation arm and attach bolt were missing with no associated impact damage. Further investigation indicated that the safety wire was missing from the actuation bolt.”
Naturally, the FAA is recommending all pilots verify the presence of the safety wire before further flight. Because the bolt head faces down, it’s critical that the safety wire is in place to keep the bolt from falling out of the actuator. The FAA says that “Cirrus aircraft will be updating their recommended pilot preflight walk around to better define the examination of the aileron area and the Maintenance Manuals to emphasize the requirement of proper safety wiring of associated hardware. We recommended that all operators adopt the new manual practices and revisions.”
