A320
Flight Crew Air Transport Pilot (ATP)
Flight Crew Type 8185
Troubleshooting; Communication Breakdown; Confusion
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Procedure; Aircraft
Our aircraft came in with a spoiler fault on the #4 spoiler. The mechanics attempted to fix; then decided to defer the spoiler inoperative. My First Officer (FO) and I watched the mechanics (as many as 4 with a lead mechanic) work on this problem for more than an hour. They finished the work and told us that the #4 spoiler was now deferred inop. We re-boarded the aircraft; received a new maintenance release and [a dispatch] release from dispatch. After pushback we started both engines; accomplished all checklists including the crew actions from the MEL card. We departed IAH without any problem and climbed to a cruise altitude of FL350. Almost an hour into flight we got a flt/cntrl spoiler fault ECAM with spoilers inop 2+4. We went to the spoiler fault procedure in the QRH and ran through the procedure and found that the only concern was runway length since the spoilers showed no deflection and we had no other faults associated with our condition. We called dispatch and maintenance control on the radio. We determined that the ZZZ mechanics had indeed inop'd the wrong spoiler set and that spoiler set #4 was not inop'd. We now had spoiler set #2 and #4 inop. We worked with dispatch and calculated using two spoiler fault landing distance that we had enough runway at LGA based on weight and weather conditions to continue to destination. While continuing our flight the FO and I determined that somehow we [had] misidentified the spoiler set with the amber xx'S displayed on the flt/cntrl page while accomplishing the crew actions of the MEL card. How we missed this I'm not sure but a couple things come to mind. As English readers and writers we read and write left to right. I also have a lot of time flying the B-727. That aircraft counts spoilers left to right. The spoilers don't show numbers on the flt/cntrl ECAM page in this situation. We trusted that the mechanics had done the work correctly after more than an hour working on the plane; and that what was displayed on the flight control page must be right. For all these reasons we forgot for a moment that A-320 spoilers count 1-5 inboard to outboard. Both pilots in this case have many hours flying the A-320. My thinking is that if this can happen to us it certainly can happen to others; especially a newly experienced A-320 crew.
Despite a prior spoiler set fault having been diagnosed; inop'd and deferred by Maintenance prior to departure the flight crew of an A320 subsequently received the same fault message after departure. Maintenance later determined the incorrect spoiler set had been inop'd.