HGS CAT III Equipements

Jetairfly1Jetairfly1
in General

Hi everyone,

I was recently doing an ILS CAT III through the HGS and I realized that something was missing in the Majestic.

Indeed, to perform a CAT III Approach, you need a third NAV instruments (which in the real Q400 which I fly, is situated next to the STBY COMM 1 panel, FWD of the power quadrant) as a redundancy for the ILS signal.

Is this something which is planned to be added to complete the LVP experience ?

Thank you !

Comments

  • FraPreFraPre

    Do you have a picture of the NAV instrument, have I never noticed it on pictures or videos?

  • hukkenhukken

    Does not seems like every Q400 is equipped with this redundancy NAV radio.

    With and without

    I guess if it's not equipped with this redundancy NAV radio it is not certified to commit ILS CAT III approaches?

  • kroswyndkroswynd

    Hi,
    Thank you for the input regarding this. Back in the early development phase of this aircraft the aircraft allowed to us did not have a third NAV radio which as you rightly mention is located next to the STBY COM, you may notice that the spot is there.

    At this time it is not feasible to comment on whether LVP approaches will be added. We will have to have access to all technical data supporting its functionality to consider its implementation, and also depending on the additional time required to implement it are factors we need to consider (they are features we would like to eventually be able to add to its operation).

    Cheers

  • Jetairfly1Jetairfly1

    Hi Kroswynd,

    Thanks for your explanation ! =)

    If you need more inputs from me don't hesitate to beep me.

    Hi FraPre and Hukken,

    Here is the NAV3 panel in the cockpit.

    I actually fly in the same airline as "Mycockpitview" so that's why it is there as well :smiley:
    Normally, the HGS needs this 3rd redundancy in order for it to switch to AIII mode which is for CAT III HGS approaches.

    When we do CAT II Autopilot approaches, we do not use this 3rd NAV panel.

    Have a good day !

  • FraPreFraPre

    Thx

  • zedlinzedlin
    Interesting, at my airline we use Nav 3 for both CAT II and III approaches
  • Jetairfly1Jetairfly1

    @zedlin
    Well, we'll use the Nav 3 for both HGS CAT II and HGS CAT III as well. =)

    However, if we have fly a CAT II approach, it will most probably be an AP CAT II instead. We avoid putting the Nav 3 for the AP CAT II to avoid launching the HGS logic while you're not using it.

  • zedlinzedlin

    @Jetairfly1 said:
    @zedlin
    Well, we'll use the Nav 3 for both HGS CAT II and HGS CAT III as well. =)

    However, if we have fly a CAT II approach, it will most probably be an AP CAT II instead. We avoid putting the Nav 3 for the AP CAT II to avoid launching the HGS logic while you're not using it.

    Interesting. Do you do PMA approaches for CAT II? For us CAT II and III are flown the same, by the captain with the HGS in AIII mode. Can't say I've heard of "AP CAT II" before.

  • Jetairfly1Jetairfly1

    @zedlin

    I guess you could say it's like a monitored approach yes =)

    The copilot will fly the plane through the Autopilot until the CAT II DH and :

    • if the runway is in sight by the captain, the captain will take over and perform the landing
    • if the runway is not in sight, the copilot will keep the controls and fly the Go-around.

    For the AP CAT II we also need the DUAL FD message to appear on the PFD by 1100' latest so that we're sure both FGM are flying the plane on the approach.

    While this procedure exists, in practice during LVO, we will fly an HGS CAT III most of the times. =)

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