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Question about ILS/Missed Approaches/Alt Airports

  • Hi There,

    I flew YYZ-LGA on AC720 on Friday April 11, 2008. Flight was delayed coming out of YYZ, we used E90 instead of scheduled A320 so I assume it was because of weather delays..

    Anyhow, flying into LGA we had to hold for about 20 mins then went into approach to LGA. We were coming into land when all of a sudden, a big roar, full power applied and very very steep climb. Was quite exciting... looked at the guy beside me and said "thats a missed approach", he didnt look too excited. In fact people around the plane didnt look so "well"...

    At this point I really missed united's channel 9 to know why we did a missed approach. (previously i flew into denver and we had a missed approach because of microbursts, but not as thrilling of a climb as this one).

    The captian came on to say that he did not see the approach lights and could not see the runway lights and that they were looking at plan B. Anyway plan B was to try again and if not sucessful they would go to the alternate which was YUL....

    After a long story, we were able to land in LGA on our second attempt...which followed a large applause from the cabin. But I was hoping I could be enlightened through a few questions.

    1. What would our decision height have been given we were in a E90 and landing in LGA. How low were we when the captian initiated a missed approach. What cat ILS would we have been using?

    2. Why is our alternate YUL? I would assume it wouldnt be JFK or EWR because of the same weather patterns right?? Wouldnt it be easier to go to IAD or something, at least stay in the United States?

    3. I think i had one more, but cant remember it now..

    Thanks everyone :-)


  • Pure supposition on my part but I would think the ground warning would come on based on a combination of descent rate, max or planned landing weight and max rated thrust plus a reasonable allowance of "just in case". So you might not have been all that low when the captain gassed it and went for the second approach.

    I would think that on military aircraft, ground warnings come on more or less within spitting distance of the ground.

    P.S. Sounds like an exciting end to a flight! Glad you guys all walked away from it.


  • Are AC e90 aircraft and pilots CATIII certified?


  • I'd consider it 3 factors

    Airport equipment/certification
    Airplane equipment/certification
    Pilot certification

    The 2 runways at YYZ that have Cat III approaches are 05 and 06L
    The published minima are
    Rwy 05
    Cat II 635' ASL/100' AGL and 1200' RVR
    Cat IIIa 600' RVR
    Cat IIIb/c not authorized

    Runway 06L
    Cat II 664' ASL/100' AGL and 1200' RVR
    Cat IIIa 600' RVR
    Cat IIIb/c not authorized

    That being said some/most operators have varying limits based on the crew/airplane qualifications. The normal Cat I limits are 200' ceiling and 2400' RVR but I've worked flights that have told me their Cat I limits are anywhere from 1200' to 3600'

    That's interesting info. I'm surprised that YYZ does not have 0/0 certified equipment. But I'm sure they conduct autolands all the time?


  • Autolands in visual conditions are conducted regularly.

    Autolands in 00/00 are a whole different kettle of fish.

    Taupo.. landing minima is based on company requirements and standards, Government Approvals, Airport facilities, Aircraft certification, ect.. anyone one thing not in approval would stop the crew from conducting the approach.

    I routinely fly into places that I am limited by that airports/countries regulations, not that of my company, flag country.

    I don't know if AC E175's are Cat 2, but again one would think as a minima they would have it.


  • It certainly sounds like your missed approach was weather related but "Go arounds" are actually more frequent than you may realize. They could be the result of a multitude of things, like: obstruction on the runway (another plane clearing more slowly than anticipated by ATC, obstruction on runway (animal, vehicle etc), weather, geese (yes geese!), simply pilots discretion (too low/high on approach), etc etc etc.

    The missed approach is actually a safety event - all the necessary guarantees are not in place so the best option is to "go around" and try again! Certainly nothing to be concerned about. Happens at YYZ several times a day!


  • Marc can correct me here if need be, but I think it also depends on company policy. Airplane and airport may have certain decision parameters, the airline may have more stringent ones.


  • Decision height is based on a number of things

    A standard CAT 1 ILS is 200' above the ground. If there were no obstacles and the crew held (which they do) basic IFR ratings (Instrument Flight Rules), They can descend to 200' or as published on the chart.

    There is Cat 2 ILS which allows descent to 100' above ground based on aircraft equipment and crew / operator training.

    Then there is Cat 3 and Cat 3 A/B which allows 50' and 00 (autoland).
    Again these require both approved aircraft, approved Runways, training, and operator approval from the regulatory authority.

    On my current aircraft we can Autoland on 00', but that takes lots of extra sim training and mostly, airports with the right systems in place.

    I have NO idea what AC's Embraers are rated to, but I imagine it's Cat 2 atleast.


  • I'd consider it 3 factors

    Airport equipment/certification
    Airplane equipment/certification
    Pilot certification

    The 2 runways at YYZ that have Cat III approaches are 05 and 06L
    The published minima are
    Rwy 05
    Cat II 635' ASL/100' AGL and 1200' RVR
    Cat IIIa 600' RVR
    Cat IIIb/c not authorized

    Runway 06L
    Cat II 664' ASL/100' AGL and 1200' RVR
    Cat IIIa 600' RVR
    Cat IIIb/c not authorized

    That being said some/most operators have varying limits based on the crew/airplane qualifications. The normal Cat I limits are 200' ceiling and 2400' RVR but I've worked flights that have told me their Cat I limits are anywhere from 1200' to 3600'


  • Hi Marc, did you know we've now got 2 Cat III approaches in YYZ? 06L and 05. About bloody time.







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