Narrative:

During cruise at FL370 the captain was flying and I was the pilot monitoring (pm). We heard a 'triple click' sound indicating a degradation of the aircraft's approach capability. The captain selected the sts button and we saw two status messages: 'autopilot 2' and 'CAT 3 dual'. We then noticed that the pfd displayed '1 FD 1'. At that time; I went to the flight plan page on the FMGC2 and saw that the scratchpad displayed 'opp FMGC in process'. The captain and I both agreed that we lost the FMGC 2. We checked for popped circuit breakers and did not find anything obvious to indicate what caused the failure. As the pm; I created a maintenance returned monitoring (mrm) and wrote up the issue including all of the indications we observed. The captain and I agreed on the text of the report and we sent it via ACARS.a few moments later; the captain looked at the QRH to see if an inflight reset procedure was available for the indications we had. He identified an in-flight reset procedure in the QRH titled; 'FMGC single failure'. After he was finished looking at the procedure; he asked me to review it to see if we were both understanding the procedure correctly - which listed two circuit breakers associated with the fmgcs. He stated he was under the impression we needed to pull both circuit breakers and asked me to look at the procedure to verify that were both under the same impression. I reviewed the reset boxed portion of the procedure. Both of us discussed the procedure and we were in agreement with the circuit breakers; their location; and our interpretation of the reset itself.to accomplish the procedure; the captain disconnected the autopilot and we followed step 1; 'before resetting fmgcs; turn off fds'. After that; we confirmed the location of the FMGC1 circuit breaker and the FMGC2 circuit breaker. Having misinterpreted the QRH intentions and thinking we were resetting the communication logic between the fmgcs - not the whole computer itself - we confirmed each breaker and then I pulled both. We left them pulled for 5 seconds as per the reset. Upon pushing both breakers in; we realized we must have done something wrong because we lost everything in both fmgcs. We also received caution messages which appeared quickly and then most disappeared within a few seconds on their own. The captain and I addressed two ecams that were left; verified the fmas; and then he re-engaged the autopilot.captain immediately put in a new destination into the FMGC and then we agreed I would fly while he reprogrammed the FMGC. His FMGC operated normally as it had before the reset but had no information. Within seconds of the reset; ATC instructed us to proceed direct to fak so there was no deviation from our flight path or ATC instructions. This instruction was complete coincidence but immediately helpful given the situation. We proceeded directly to fak and each of us confirmed that all information was reprogrammed into the FMGC1. Once complete with the FMGC; we transferred controls for the captain to resume pilot flying duties as I resumed pm duties. We then sent another mrm to report the circuit breaker resets as per the QRH.finally; we reviewed the procedure to see what we had done wrong. I found that I interpreted the procedure to indicate that both circuit breakers should be pulled not only because of an expectation bias because (we had just been instructed to turn off both flight directors before resetting both fmgcs) but also because the procedure uses an apostrophe to indicate the possessive form of speech for 'system's' instead of what I misread as the plural form 'systems'. While reading the procedure the first time; and performing normal radio calls; I either didn't see the apostrophe or didn't interpret it in a way that I thought it was indicating I would have to choose only one FMGC. I also never thought we would lose the information in the FMGC (we never lost any information from the ACARS during this process).we proceeded to [destination] without incident.

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Original NASA ASRS Text

Title: A319 First Officer reported deviating from checklist procedure while dealing with an FMGC failure.

Narrative: During cruise at FL370 the Captain was flying and I was the Pilot Monitoring (PM). We heard a 'triple click' sound indicating a degradation of the aircraft's approach capability. The Captain selected the STS button and we saw two status messages: 'AUTOPILOT 2' and 'CAT 3 DUAL'. We then noticed that the PFD displayed '1 FD 1'. At that time; I went to the FLT PLAN page on the FMGC2 and saw that the scratchpad displayed 'OPP FMGC IN PROCESS'. The Captain and I both agreed that we lost the FMGC 2. We checked for popped circuit breakers and did not find anything obvious to indicate what caused the failure. As the PM; I created a Maintenance Returned Monitoring (MRM) and wrote up the issue including all of the indications we observed. The Captain and I agreed on the text of the report and we sent it via ACARS.A few moments later; the Captain looked at the QRH to see if an inflight reset procedure was available for the indications we had. He identified an in-flight reset procedure in the QRH titled; 'FMGC SINGLE FAILURE'. After he was finished looking at the procedure; he asked me to review it to see if we were both understanding the procedure correctly - which listed two circuit breakers associated with the FMGCs. He stated he was under the impression we needed to pull both circuit breakers and asked me to look at the procedure to verify that were both under the same impression. I reviewed the reset boxed portion of the procedure. Both of us discussed the procedure and we were in agreement with the circuit breakers; their location; and our interpretation of the reset itself.To accomplish the procedure; the Captain disconnected the Autopilot and we followed step 1; 'Before resetting FMGCs; turn off FDs'. After that; we confirmed the location of the FMGC1 Circuit breaker and the FMGC2 Circuit breaker. Having misinterpreted the QRH intentions and thinking we were resetting the communication logic between the FMGCs - not the whole computer itself - we confirmed each breaker and then I pulled both. We left them pulled for 5 seconds as per the reset. Upon pushing both breakers in; we realized we must have done something wrong because we lost everything in both FMGCs. We also received Caution messages which appeared quickly and then most disappeared within a few seconds on their own. The Captain and I addressed two ECAMs that were left; verified the FMAs; and then he re-engaged the Autopilot.Captain immediately put in a New Destination into the FMGC and then we agreed I would fly while he reprogrammed the FMGC. His FMGC operated normally as it had before the reset but had no information. Within seconds of the reset; ATC instructed us to proceed Direct to FAK so there was no deviation from our flight path or ATC instructions. This instruction was complete coincidence but immediately helpful given the situation. We proceeded directly to FAK and each of us confirmed that all information was reprogrammed into the FMGC1. Once complete with the FMGC; we transferred controls for the Captain to resume Pilot Flying duties as I resumed PM duties. We then sent another MRM to report the circuit breaker resets as per the QRH.Finally; we reviewed the procedure to see what we had done wrong. I found that I interpreted the procedure to indicate that BOTH circuit breakers should be pulled not only because of an expectation bias because (we had just been instructed to turn off BOTH Flight Directors before resetting BOTH FMGCs) but also because the procedure uses an apostrophe to indicate the possessive form of speech for 'system's' instead of what I misread as the plural form 'systems'. While reading the procedure the first time; and performing normal radio calls; I either didn't see the apostrophe or didn't interpret it in a way that I thought it was indicating I would have to choose only one FMGC. I also never thought we would lose the information in the FMGC (we never lost any information from the ACARS during this process).We proceeded to [destination] without incident.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.