A319 flight crew reported a misapplied MEL and misunderstood MEL procedures caused complication on arrival at destination airport when the autopilot would not disengage during landing.

2022-01 · NASA ASRS report 1867341

Date: 2022-01 · Aircraft: A319

Anomalies: aircraft-equipment-problem-critical|deviation-discrepancy-procedural-far|deviation-discrepancy-procedural-mel-cdl|deviation-discrepancy-procedural-published-material-policy

Synopsis

A319 flight crew reported a misapplied MEL and misunderstood MEL procedures caused complication on arrival at destination airport when the autopilot would not disengage during landing.

Narrative

We failed to run MEL 27-XXX (X) procedures and flew the aircraft in an unsafe configuration due to ELAC 1 being left off. Background - we returned to the gate for a F/CTL ELAC 1 PITCH FAULT ECAM. Reset from QRH was unsuccessful. Maintenance was called and they performed action for MEL 27-XXX ELAC 1 PITCH FAULT; including securing circuit breakers in the flight deck and electronics bay and selecting the ELAC 1 push button to OFF. Following Maintenance; the ECAM displayed F/CTL ELAC 1 FAULT" with ECAM actions of "- ELAC 1...OFF THEN ON. IF UNSUCCESSFUL: - ELAC 1...OFF" and "C/B TRIPPED ON OVHD PNL TRIPPED R ELEC BAY." At this point; I told Maintenance and the CA (Captain) that the F/CTL ELAC 1 FAULT ECAM was not expected and not noted in documentation for MEL 27-XXX. I also made them aware that this ECAM display was noted in MEL 27-XXY; ECAM FAULT.Maintenance was in the flight deck. The CA and Maintenance both said that was normal. MEL 27-XXX (Z) Procedures Step X states; "At initial placarding and prior to each departure; deactivate ELAC 1 in accordance with AMM 27-93-00-040-001-A." This note was used to belay my concerns that the ELAC 1 FAULT ECAM was OK. The ECAM was not performed and the CA used emergency cancel to clear all the ECAMs. Maintenance left and I then began to review the (X) procedures for MEL 27-XXX; and was stopped by the CA; who said there was no need to run the procedures because the "F/CTL ELAC 1 PITCH FAULT alert" was not displayed as discussed in (X) E.1 (DURING COCKPIT PREPARATION; prior to starting engines; if the F/CTL ELAC 1 PITCH FAULT alert is displayed...). I stated we still needed to run (X) E.2-5; but the CA told me (X) E.1.j; "After 5 seconds do the following checks:" proves that those steps were only done if Step Y was done; and Step Y is only done if you have the F/CTL ELAC 1 PITCH FAULT alert. I stated this was incorrect and we would be taking off without checking any of the SECs (Spoiler Elevator Computers) or that our flight control back-ups worked. I was assured that Dispatch and Maintenance both agreed that this was the proper interpretation of the MEL. Again; I expressed my concern about the ELAC 1 FAULT and that this was not in the MEL and was told sometimes I needed to just trust what people told me. We started engines and ran all the checklists; including the F/CTL checks; without any issue. We took off with ELAC 1 OFF; related ECAMs emergency cancelled; and without doing any (X) procedures for MEL 27-XXX. Climb; cruise; and descent were uneventful.Upon arrival into ZZZ1; we performed a visual backed up with the ILS to XXL. I was the pilot flying. I coupled A/P (Autopilot) 1 and 2 for the ILS. At approximately 1300 ft.; I disconnected A/P via the side stick switch. Only A/P 2 disconnected. This was due to the ELAC 1 being OFF. We were not aware this was a symptom of a secured ELAC 1. The CA took controls briefly to confirm his side stick A/P disconnect worked. Controls were given back to me just before 1000 ft. and I continued the approach and landing without the use of A/P 1 or 2. The landing was uneventful; other that the roll control in the flare not being smooth. I noted all this to the CA. At the gate; the CA wrote up the FO (First Officer) A/P switch and maintenance was performed to lubricate it. I reviewed SAFE and saw a follow-on flight wrote up the F/CTL ELAC 1 FAULT ECAM and Maintenance referred them back to MEL- 27-XXX.The (X) procedures were not performed for MEL 27-XXX. Step Z.1 has the flight crew returning to a normal configuration and turning the ELAC 1 P.B. SW ON. This would have prevented this safety issue. In addition; there are no notes in the MEL that alert flight crews they will see F/CTL ELAC 1 FAULT or the C/B-tripped ECAMs prior to performing the (X) procedures; as is the case in MEL 27-XXY. MEL 27-XXX (Z) Procedures Step X says to deactivate ELAC 1 and this led to the CA's assumption the ELAC 1 would be left OFF. I went along with the CA's suggestion Ishould trust Dispatch and Maintenance without MEL documentation to support it. The CA is a Check Airman; and although not an issue through the process; it was the last thing I told myself as we took the runway.(X) E.1 should clarify that if "PITCH FAULT" is displayed; do Step Y then 2-5; and if "PITCH FAULT" is not displayed; skip Step Y and do A-B. The MEL should include notes about F/CTL ELAC 1 FAULT and CB TRIPPED ECAMs."

Second reporter narrative

I was the Captain for Aircraft X; ZZZ to ZZZ1; on Date. After both engines were started; we received a F/CTL ELAC 1 PITCH TRIM fault on the ECAM. After accomplishing the NNM (Non-normal MEL Procedure); we contacted Dispatch and Maintenance for help. Maintenance asked us to attempt a computer reset using the procedure found in the QRH. Two reset attempts were made; both unsuccessful. Maintenance and I discussed crew-placarding the MEL but after looking at the MEL; we discovered that was not allowed. We returned to the gate. Maintenance met the flight and attempted several more resets without success. Maintenance then decided to defer the malfunction and that MEL 27-XXX would be applied to the aircraft.MEL 27-XXX required Maintenance to deactivate ELAC 1 and that a maintenance write-up must be made prior to each flight. There are also operational procedures that must be considered prior to departure. After Maintenance deactivated ELAC 1; the F/CTL ELAC 1 fault was displayed on the EWD (Electronic Wiring Diagram) along with the C/B OPEN ECAMs for the two C/B that were pulled on 49VU and 105VU. ELAC 1 P/B on the O/VHD panel was set to OFF.Prior to being released by Maintenance; in preparation for departure; both the FO (First Officer) and I reviewed the Operational Procedures for MEL 27-XXX. We discovered a conditional statement in the fifth item that led me to believe that we may not have to accomplish the Operational Procedures. Item E states; DURING COCKPIT PREPARATION; Step Y - Prior to starting engines; if the F/CTL ELAC 1 PITCH fault alert is displayed on the EWD; check the elevator and roll spoilers control through the SECs (Spoiler Elevator Computers) as follows:".Step Y walks you through setting up the O/VHD panel P/Bs for the control checks. There are nine actions labeled a through i. Action item j. states; "After 5 seconds do the following checks:" and the word (Continued) is printed below it. Steps A and B would then be accomplished based on the actions accomplished in Step Y. Step Z returns the OVHD panel back to a normal configuration but is only done so after accomplishing Steps Y; A and 3. I interpreted Item E; Step Y to say that since I did not have the F/CTL ELAC 1 PITCH fault; I was not required to accomplish the Operational Procedures found in Steps Y; A; C and Z and not required to read any further.The FO (First Officer) disagreed with me and thought that we should omit Step Y but continue to do the elevator and roll spoilers control checks found in Steps A and C and reconfiguration Step Z. Attempting to resolve our differences; we asked the Mechanic who did the work to read the MEL Operational Procedure and give his opinion. He was not sure but agreed with me that we had not met the conditional statement regarding the F/CTL ELAC 1 PITCH fault being displayed - therefore; we did not have to proceed with the Operational Procedure. The FO still disagreed so we contacted Maintenance for clarification. The Maintenance Official in Maintenance read the MEL Operational Procedure and he also agreed with me that we had not met the conditional statement regarding the F/CTL ELAC 1 PITCH fault being displayed - therefore; we did not have to proceed with the Operational Procedure. The FO was now satisfied that we had been given good information and we elected to depart the gate. During taxi; the FO and I discussed that the F/CTL Check in the BEFORE TAKEOFF FLOW would ensure proper flight control movement and control and we agreed that this was a safe operation.Approach and landing; the FO was acting as pilot flying and the flight was accomplished successfully without incident. Upon arrival; the FO used the ILS approach procedure for ZZZ1 XXL as a backup to the visual approach as per our SOPs. When cleared for the visual approach; the FO engaged the second AP (Autopilot); AP 1; as per procedure. Prior to landing; the FO disengaged the AP using his TAKEOVER P/B on his side stick but only AP 2 disengaged. Since wewere on short final; we did not spend any time troubleshooting the problem. Instead; we agreed that this must be associated with ELAC 1 being deactivated. We landed successfully without incident and taxied to the gate.Later that night I reviewed the MEL again to see if we missed anything; attempting to explain why we disagreed on what to do and to see if there was any mention of how the AP system was affected by the maintenance procedure and configuration. I believe that the verbiage and the sentence structure used in MEL 27-XXX needs to be rewritten to be more definitive and easier to understand.The pressures associated with such a complex malfunction and operational on-time performance can cause pilots to quickly read the instructions but not really understand what is to be accomplished. Pilots need to be able to read the information and know exactly what to do and how this situation affects their aircraft without any ambiguity. I then compared the other ELAC MEL procedures and found that MEL 27-XXY had similarities to MEL 27-XXX; the MEL we used; and found the answer to the side stick TAKEOVER P/B issue. At the end of MEL 27-XXY; there is a note explaining how deactivating ELAC 1 affects the FO's TAKEOVER P/B and how to use the AP system as a result. Adding this information to MEL 27-XXX would also be advisable.Further study of MEL 27-XXY showed that the same elevator and roll spoilers control checks found in MEL 27-XXX should be accomplished only if F/CTL ELAC 1 fault is displayed on the EWD. As a result of ELAC 1 being deactivated; we did have the F/CTL ELAC 1 fault is displayed on the EWD. This leads me to ponder two possibilities: Were we given the correct MEL; in other words; should we have been using MEL 27-XXY instead of MEL 27-XXX? Or; should we have been given both MEL 27-XXX due to the original malfunction of the ELAC 1 PITCH TRIM fault and MEL 27-XXY due to the deactivation of ELAC 1? If we were given MEL 27-XXY alone or in combination with MEL 27-XXX; we would have accomplished the elevator and roll spoilers control checks found in Steps A and C and we would also have accomplished Step Z which reconfigures the OVHD panel back to a normal configuration. If we were given MEL 27-XXY alone or in combination with MEL 27-XXX; we would also have been made aware of how the AP system was affected by the deactivation of ELAC 1.I suggest a deep dive into these MEL procedures to ensure that they are correct; meaning: that the necessary actions are clearly defined; that the verbiage is clear and understandable; that any effect caused by the maintenance procedures are clearly noted to eliminate any unexpected surprises; [and] that any aircraft conditions or configurations that result from the maintenance procedures are explained and the consequences of those changes are dealt with."

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.

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