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ID No. Q12041 (separation on same ILS)

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  • ID No. Q12041 (separation on same ILS)

    Minimum Radar Separation on final approach: Provided there is no danger of wake turbulence, the minimum radar separation provided between aircraft established on the same localizer course shall be not less than;

    My answer 3.0 NM

    Database answer 2.5 NM

    ICAO 4444 answer

    13.4.2 A minimum of 300 m (1 000 ft) vertical or a
    minimum of 5.6 km (3.0 NM) radar separation shall be
    provided between aircraft during turn-on to parallel ILS
    localizer courses and/or MLS final approach tracks.

    13.4.3 The minimum radar separation to be provided
    between aircraft established on the ILS localizer course and/or
    MLS final approach track shall be:

    a) 5.6 km (3.0 NM) between aircraft on the same ILS
    localizer course or MLS final approach track unless
    increased longitudinal separation is required due to
    wake turbulence; and

    b) 3.7 km (2.0 NM) between successive aircraft on
    adjacent ILS localizer courses or MLS final approach
    tracks.

  • #2
    Hi,

    ICAO Doc 4444 Para 8.7.4.2 (b)
    4.6km (2.5 NM) between suceeding aircraft which are established on the same final approach track within 18.5km (10NM) of the runway end.

    BGS notes page 222.

    Baz

    Comment


    • #3
      Re: ID No. Q12041 (separation on same ILS)

      I've been quite confused by these separation on final questions. Indeed it is possible for the separation to go down to 2.5NM, "subject to runway occupancy times etc" as the BGS notes put it. Doc. 4444 lays down a number of conditions for this to be allowed:

      7.4 Radar separation minima
      7.4.1 Unless otherwise prescribed in accordance with
      7.4.2, 7.4.3 or 7.4.4, or Part IV with respect to independent
      and dependent parallel approaches, the horizontal radar
      separation minimum shall be 9.3 km (5.0 NM).
      7.4.2 The radar separation minimum in 7.4.1 may, if so
      prescribed by the appropriate ATS authority, be reduced, but
      not below:
      a) 5.6 km (3.0 NM) when radar capabilities at a given
      location so permit; and
      b) 4.6 km (2.5 NM) between succeeding aircraft which
      are established on the same final approach track
      within 18.5 km (10 NM) of the runway end. A
      reduced separation minimum of 4.6 km (2.5 NM) may
      be applied, provided:
      i) the average runway occupancy time of landing
      aircraft is proven, by means such as data collection
      and statistical analysis and methods based on a
      theoretical model, not to exceed 50 seconds;
      ii) braking action is reported as good and runway
      occupancy times are not adversely affected by
      runway contaminants such as slush, snow or ice;
      iii) a radar system with appropriate azimuth and range
      resolution and an update rate of 5 seconds or less
      is used in combination with suitable radar
      displays; and
      iv) the aerodrome controller is able to observe,
      visually or by means of surface movement radar
      (SMR) or a surface movement guidance and
      control system (SMCGS), the runway-in-use and
      associated exit and entry taxiways;
      v) wake turbulence radar separation minima in 7.4.4
      below, or as may be prescribed by the appropriate
      ATS authority (e.g. for specific aircraft types), do
      not apply;
      vi) aircraft approach speeds are closely monitored by
      the controller and when necessary adjusted so as to
      ensure that separation is not reduced below the
      minimum;
      vii) aircraft operators and pilots have been made
      fully aware of the need to exit the runway in an
      expeditious manner whenever the reduced
      separation minimum on final approach is
      applied; and
      viii) procedures concerning the application of the
      reduced minimum are published in
      Aeronautical Information Publications.
      This particular question makes no mention of these special conditions. Also, the passage above makes no mention of "localizer". I believe the appropriate regulations in this case are those quoted by Redcoat, and I suspect the answer, "2.5NM" is based on a misunderstanding of the regulations.

      If I am correct this would explain why the answer 3.0NM is the only one on offer in the following question:

      Q1916
      Question: The minimum radar separation to be provided to aircraft established on the localizer course shall be: 3.0 NM between aircraft on the same localizer course.

      Info:You can only choose one of the four answers offered; you can't write a fifth answer because you think it is better.

      In this case a better answer would have been 2.5nm but as it's not present, 3nm is the best available.
      Also on this subject, in this thread we are asked to accept that two practically identical questions are intended to have different answers. I read, "with additional longitudinal separation as required for wake turbulence" as referring to the regulation, "(3.0 NM) between aircraft on the same ILS localizer course... unless increased longitudinal separation is required due to wake turbulence". I do not accept that 5.0NM is a reasonable answer and I believe in both cases the answer should be 3.0NM.

      I am due to be examined on this subject next week and I have no confidence that the answers provided to these questions are actually correct. I would appreciate any advice.

      Comment


      • #4
        Re: ID No. Q12041 (separation on same ILS)

        The minimum separations are:
        2? nm between two aircraft on the same localizer course
        or
        2 nm between two aircraft on adjacent localizer courses approaching parallel runways.

        Q12041:
        Minimum Radar Separation on final approach. The minimum radar separation provided between aircraft established on the same localizer course shall be: (plus additional longitudinal separation as required for wake turbulence)

        Answers offered are 2, 2?, 3 or 5 nm. Correct answer 2? nm.

        Q1916:
        The minimum radar separation to be provided to aircraft established on the localizer course shall be:

        Answers offered are:
        3.0 NM between aircraft on adjacent localizer course. Wrong - it can come down to 2 nm
        5.0 NM between aircraft on the same localizer course. Wrong - it can come down to 2? nm
        2.0 NM between aircraft on the same localizer course. Wrong - 2 nm is not enough
        3.0 NM between aircraft on the same localizer course. Best answer so far. since answers are all to the nearest mile, not ? mile, this is the examiner's prefered answer.

        Baz

        Comment


        • #5
          Re: ID No. Q12041 (separation on same ILS)

          why we need to worry about this sort of thing when we are under radar control I don't know.... let the ATC do his/her job.......

          study hard learning all the questions everyone

          Comment


          • #6
            Re: ID No. Q12041 (separation on same ILS)

            Other sources give different answers to some of these questions, for example:

            http://academy.antalyava.org/info/AirlawATC.pdf

            The following minimum radar separation shall be provided between aircraft on the same localizer with additional longitudinal separation as required for wake turbulence:
            a 2 NM.
            b 3 NM. <
            c 5 NM.
            d 2.5 NM.

            The minimum radar separation to be provided to aircraft established on the localizer course shall be:
            a 3.0 NM between aircraft on adjacent localizer course.
            b 3.0 NM between aircraft on the same localizer course. <
            c 2.0 NM between aircraft on the same localizer course.
            d 5.0 NM between aircraft on the same localizer course.

            Which radar separation minima is applicable between succeeding aircraft established on the same final approach track within 10 nm of the runway?
            a 2.5 nm. <
            b 3 nm.
            c 4 nm.
            d 5 nm.

            Which wake turbulence radar separation minima shall be applied between a HEAVY aircraft and a succeeding MEDIUM aircraft during the approach and departure phases of a flight.
            a 2.5 nm.
            b 4 nm.
            c 5 nm. <
            d 6 nm.
            Note the first two questions ask about "same localizer", the third question asks about "same track within 10nm" and has a different answer to the first two. The question asking about wake turbulence gives the wake turbulence categories necessary to answer that question.

            Comment


            • #7
              Re: ID No. Q12041 (separation on same ILS)

              What is the source of these questions ?

              Comment


              • #8
                Re: ID No. Q12041 (separation on same ILS)

                There's a link to the source at the start of the quote above. Appears to be taken from a database of questions simliar to the QB.

                Comment


                • #9
                  Re: ID No. Q12041 (separation on same ILS)

                  Seems to be a Turkish company, Antalya.va, .va meaning .co ltd, as .sa in spanish means sociedad anonima

                  Similar, but not quite the same!

                  Dick

                  Comment


                  • #10
                    Re: ID No. Q12041 (separation on same ILS)

                    Ref the four questions posted yesterday by Jon H:

                    Q1: correct answer is (d) 2.5nm, not (b) 3.0nm.
                    Q2: correct answer is (b) for reasons I have given above.
                    Q3: I would go for answer (b) 3.0nm because the questions states "on the same final approach track" not "on the same localizer".
                    Q4: correct answer is (c) 5.0 nm wake turbulence separation for MEDIUM following HEAVY.

                    Baz

                    Comment


                    • #11
                      Re: ID No. Q12041 (separation on same ILS)

                      Originally posted by Baz View Post
                      Q1: correct answer is (d) 2.5nm, not (b) 3.0nm.
                      So you accept the answer is not 5.0NM, as stated by Q1915?

                      Originally posted by Baz View Post
                      Q3: I would go for answer (b) 3.0nm because the questions states "on the same final approach track" not "on the same localizer".
                      I think you've made a mistake. Doc 4444 gives these numbers and conditions the opposite way around (my bold).

                      13.4.3 The minimum radar separation to be provided
                      between aircraft established on the ILS localizer course and/or
                      MLS final approach track shall be:

                      a) 5.6 km (3.0 NM) between aircraft on the same ILS localizer course...
                      7.4.2 The radar separation minimum in 7.4.1 may, if so
                      prescribed by the appropriate ATS authority, be reduced, but
                      not below:
                      a) 5.6 km (3.0 NM) when radar capabilities at a given
                      location so permit; and
                      b) 4.6 km (2.5 NM) between succeeding aircraft which
                      are established on the same final approach track
                      within 18.5 km (10 NM)
                      of the runway end.
                      Or as the BGS notes put it:

                      PANS-ATM - Approach and Aerodrome
                      Radar Separation Minima
                      2.5 nm: between succeeding aircraft established on the same approach track subject to average runway occupancy time, braking action, radar rate of update, wake turbulence separation etc.

                      *The minimum radar separation between aircraft established on the ILS localizer is 3.0 nm between aircraft on the same ILS localizer course and 2.0 nm between successive aircraft on adjacent ILS localizer courses.
                      Last edited by jon h; 31-08-2011, 18:22. Reason: added BGS quote

                      Comment


                      • #12
                        Re: ID No. Q12041 (separation on same ILS)

                        Originally posted by jon h View Post
                        The following minimum radar separation shall be provided between aircraft on the same localizer with additional longitudinal separation as required for wake turbulence
                        Originally posted by Baz View Post
                        correct answer is (d) 2.5nm
                        I think we agree at least that the current answer to Q1915 (5 nm) is incorrect.

                        I discovered in the archives that back in 2005 the answer was 3nm, then it was changed following a query from a student who thought the question meant wake turbulence separation was included. As discussed on the feedback forum, the wording has since been clarified to say that wake turbulence separation is excluded. Along with redcoat, nickeas and pressman, I believe the answer was correct to begin with, i.e. 3.0 nm.

                        Preparing for an exam is difficult enough without the unnecessary frustration of knowing that at least one of your answers is disputed by your school without any explanation. I hope future BGS students will get some clarification on this question.

                        Comment


                        • #13
                          Re: ID No. Q12041 (separation on same ILS)

                          We pass on the feedback we receive from a number of sources (we work with schools throughout Europe who use our training material). You may not agree with the answers we give, in fact there are occasions when we do not like the answers we are telling you to tick, but we are giving you the answers which we understand the examiners are accepting as correct. Since our results are so good (many 100% passes and the vast majority of BGS candidates in the high 90s in this subject) we must be getting it right. Congratulations on passing all your exams with such excellent results.

                          Baz

                          Comment

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