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Volaris A321 loses both ELACS

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  • Volaris A321 loses both ELACS

    A Volaris A321 lost both ELAC's and had to return to Mexico City. WIth both ELAC's offline, the ailerons are useless (damping mode) so the SEC's control roll via roll spoilers alone. Autopilots are lost and the law degrades to Alternate.

    We touched on this trying to unravel rumors about the AirAsia crash. How can you lose both ELAC's simultaneously (or nearly simultaneously)? It would have to involve either a common electrical failure or a massive coincidence (or a manual shutdown). But each is powered from a separate bus...

    ....?

    http://avherald.com/h?article=48a5ccb7&opt=0

  • #2
    What if one was already MEL'd?

    Comment


    • #3
      Originally posted by ATLcrew View Post
      What if one was already MEL'd?
      BTW, WTH does ELACS stand for?

      Sounds important IMO, and we shouldn't be flying with them MEL'd.

      Thx.
      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

      Comment


      • #4
        Originally posted by AvHerald article
        ... both ELACs (Elevator Aileron Computers) had failed causing the ailerons to become inoperative, elevator now being controlled by the SECs (Spoiler Elevator Computers), roll control achieved via spoilers controlled by SECs...
        Thank God the VCRs weren't being controlled by MTV or the trouble would have been much worse...
        Be alert! America needs more lerts.

        Eric Law

        Comment


        • #5
          Whatever happened to the English language ?

          Nothing pisses me off more than people who use abbreviations first off without defining what they mean, thereby excluding others from a conversation.
          Truly smart people use the full words first time and then subsequently use initial letters once everyone else knows what they are saying.

          Rest In Peace, English language.
          If it 'ain't broken........ Don't try to mend it !

          Comment


          • #6
            Originally posted by elaw View Post
            Thank God the VCRs weren't being controlled by MTV or the trouble would have been much worse...
            ...so on a DC-9, they're Elevator and Aileron CABLES... right...
            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

            Comment


            • #7
              Originally posted by brianw999 View Post
              Whatever happened to the English language ?

              Nothing pisses me off more than people who use abbreviations first off without defining what they mean, thereby excluding others from a conversation.
              Truly smart people use the full words first time and then subsequently use initial letters once everyone else knows what they are saying.

              Rest In Peace, English language.
              Sorry Brian... Airbus calls them ELAC's. It is an acronym for Elevator and Aileron Computer. They receive air and internal reference data and normally control these flight surfaces plus the horizontal stabilizer and also provide the pitch-related protections (high AoA protection, pitch attitude limit, high speed protection).

              If both ELAC's fail, the SEC's take over. SEC stands for Spoilers Elevator Computer, and they assume the role of elevator in a standby mode. When the ELAC's fail, they use spoilers for roll.

              It's a very serious situation to lose both ELAC's because this also means you lose autopilot and normal law protections, not to mention ailerons.

              Comment


              • #8
                Originally posted by ATLcrew View Post
                What if one was already MEL'd?
                That's a possibility but the AvHerald reported it as follows:
                ...the crew stopped the climb at 12,000 feet reporting a flight controls failure after both ELACs (Elevator Aileron Computers) had failed...
                A MEL'd ELAC also rules out dispatch for many more common failures, where the MMEL requires both ELAC's for dispatch. For instance, you can't go with a MEL'd radalt unless both ELAC's are functioning. In other words, you need a pretty shipshape airplane to go flying with a MEL'd ELAC.

                But it's possible.

                Comment


                • #9
                  Originally posted by brianw999 View Post
                  Whatever happened to the English language ?

                  Nothing pisses me off more than people who use abbreviations first off without defining what they mean, thereby excluding others from a conversation.
                  Truly smart people use the full words first time and then subsequently use initial letters once everyone else knows what they are saying.

                  Rest In Peace, English language.
                  Not sure you should be hanging out on an aviation forum...all the talk of ATC, VOR, DME, ADF, ILS, ATIS, IFR, VFR, ASI, AI, VSI, LAHSO, FMC, RNAV VNAV, GPS, and the beloved POH AND FCOM
                  Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                  Comment


                  • #10
                    The main reason for me hanging out here is to keep an eye on and, if necessary a moderating influence on those who seek to be an overbearing smartass.

                    Evan very kindly explained what it was all about and my aviation education has expanded a bit more now that I understand. A positive input has occurred.

                    Your reply on the other hand was totally unhelpful and simply confirmed your ability to be occasionally an overbearing smartass !
                    If it 'ain't broken........ Don't try to mend it !

                    Comment


                    • #11
                      Originally posted by brianw999 View Post
                      You have to admit that the aviation world kind of likes its acronyms. I concur that we often need to "spell it out" more.
                      Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                      Comment


                      • #12
                        Originally posted by 3WE View Post
                        Not sure you should be hanging out on an aviation forum...all the talk of ATC, VOR, DME, ADF, ILS, ATIS, IFR, VFR, ASI, AI, VSI, LAHSO, FMC, RNAV VNAV, GPS, and the beloved POH AND FCOM
                        I can't beleive you forgot GUMPS!

                        You know:
                        Gear down
                        Undercarriage down
                        Make sure the gear's down
                        Put the gear down
                        Sure the gear's down?



                        On a slightly more serious note and to give credit where it's due, the Avherald article did explain what the abbreviations used in the article meant.
                        Be alert! America needs more lerts.

                        Eric Law

                        Comment


                        • #13
                          Gas..Undercarriage..Mixture..Prop & and switches or seatbelts.
                          Live, from a grassy knoll somewhere near you.

                          Comment


                          • #14
                            Originally posted by elaw View Post
                            I can't beleive you forgot GUMPS!

                            You know:
                            Gear down
                            Undercarriage down
                            Make sure the gear's down
                            Put the gear down
                            Sure the gear's down?



                            On a slightly more serious note and to give credit where it's due, the Avherald article did explain what the abbreviations used in the article meant.
                            1) Kudos to Av. Herald for spelling it out- and flaming ridicule for 3BS for not clicking on the link.

                            2) I was not familiar with THAT GUMP check...it's good.

                            3) Of course, here you go bringing in broadly-applicable, fundamental, cowboy airmanship stuff instead of doing the right way and using the type-specific FCOM and memory checklist items.
                            Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                            Comment


                            • #15
                              Originally posted by Evan View Post
                              A MEL'd ELAC also rules out dispatch for many more common failures, where the MMEL requires both ELAC's for dispatch. For instance, you can't go with a MEL'd radalt unless both ELAC's are functioning. In other words, you need a pretty shipshape airplane to go flying with a MEL'd ELAC.

                              But it's possible.
                              Evan, I applaud your reading of the MMEL, but your conclusion is flawed for several reasons:

                              1. Radalt deferral is not common, in fact, in nine years with three airlines and four aircraft types I've never had one deferred.

                              2. Functioning Radalt does not a shipshape (I'm not even sure what that means) airplane make.

                              3. A deferred ELAC is a lot more common that a deferred Radalt.

                              None of which explains what happened to the airplane in question, but just food for thought. It's great to read the MMEL, but without experience with the type in question, it won't tell you much.

                              Comment

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