31 July 2011 C1 CIVIL AVIATION DEPARTMENT HONG KONG ...

AIRWORTHINESS NOTICE NO. 12APPENDIX NO. 63Functional Check and Control System Check on Fly-by-wire AircraftIssue 130 September 20041 A foreign incident investigation reported a fly-by-wire aircraft has faulty wireinstallation on the flight control system during maintenance. During the repair onthe electrical plug of an Elevator Aileron Computer (ELAC), the connections of twopairs of wires were reversed. As a result of this error, the aircraft reacted in acontrary manner during the initial climb phase of its first flight after maintenance.Right roll input from the Captain sidestick to correct a left bank of the aircraft resultedin the aircraft banked further to the left! Fortunately, by using the First Officersidestick, the aircraft landed safely without any damage and none of the passengerswas injured.2 The investigation report indicated the incident was due to a series of human factorsrelated errors and the ambiguity of manufacturer’s instructions and operator’schecklists. The subsequent functional check conducted by maintenance personnelwas only performed by using one control sidestick which failed to detect the fault.3 To prevent recurrence of similar incident, the Director-General adopts the followingwith respect to the responsibility of maintenance organisations as recommended bythe investigation report:3.1 Instructions should be issued to require that functional checks and controlsystem checks on fly-by-wire aircraft be performed by using BOTH sidesticks;and3.2 Maintenance procedures and job cards should be amended to include theabove requirement.AN-12A63 P.130 September 2004