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8 Answers

ILS or LOC RWY 10

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Instrument Rating

 The question I have is about the "ILS or LOC RWY 10" approach at DuPage Airport, West Chicago, IL (KDPA).  How would I fly the full approach using the only listed IAF, at LYLLE, if I'm coming from the north in a non GPS equipped airplane?  I don't see how I could fly direct to LYLLE to fly the procedure turn.  And, if they want me to fly direct to the DPA VOR and then fly the 329 degree outbound, how would I do that coming from the north? Would they want me to make a near 150 degree right turn to intercept the 328 radial with 2.2 miles?

8 Answers



  1. Mark Kolber on Sep 04, 2019

    In a non-vector-to-final, non-GPS world, I would expect to be routed so I approach DPA from an appropriate direction for the DPA-LYLLE transition.

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  2. Warren Webb Jr on Sep 09, 2019

    In that airspace, near Chicago, I can’t imagine a full approach ever being allowed from the north – only vectors to final. Try contacting an FBO or charter company based there and talk to one of their pilots about non-GPS arrivals from the north.

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  3. KDS on Sep 09, 2019

    While it’s extremely remote, it is best to consider those what-if situations. I can think back to a time when I was shooting a PAR approach and lightning struck. Very shortly I received “Radar contact lost” and continued on the ILS a short time after that, the ILS went down. I finished with an NDB approach from the LOM that was still working. It is not unthinkable nowadays that technical problems or enemy action could bring us down to greatly reduced navigation support.

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  4. Warren Webb Jr on Sep 09, 2019

    KDS – you are absolutely correct. I thought about emergencies but decided not to get too long since Colleen didn’t specifically mention emergencies (radar or comm radios lost). But if I had one, in this situation, I would go direct to DPA, maneuver as though I had been instructed to hold on the 148 radial (from the north a parallel entry), to align me with the R-328 feeder route and continue on the published procedure from there.

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  5. Mark Kolber on Sep 10, 2019

    I only answered the question asked – “how would I fly the full approach coming from the north?” – without reading a bunch of extra things into it or getting into likelihood in a vectoring environment, emergency scenarios or a bunch of ifs, ands, or buts.

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  6. KDS on Sep 10, 2019

    …….. and you both did excellent jobs of providing answers and advice.

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  7. Colleen on Sep 10, 2019

    Thank you for all your answers. I realize it’s highly unlikely I would ever do this as a full approach, but I try to look at each approach, asking “How would I get into this without radar vectors and only the equipment that is required by the approach plate?” I am doing this mainly for training purposes, but as stated by some of you, it’s good to look at in the case of a radio failure, or other type of emergency. As I understand, if the approach plate does not specifically require radar vectors than you should be able to enter the approach on your own using the IAF. I just don’t see how you can fly direct to LYLLE without a GPS and I do think flying direct to DPA VOR and then flying to LYLLE could be done, but why is the DPA not the IAF then?

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  8. Warren Webb Jr on Sep 12, 2019

    “why is the DPA not the IAF then?” I don’t know for sure, but I did find a statement in the TERPS that seems to fit – the initial approach segment length “must be sufficient to permit the altitude change required by the procedure”. I looked at one of the approaches at KHFD where I used to be based and that guideline I quoted seems to fit perfectly. For the LDA RWY 02 approach, there are two vor’s associated with the approach, each providing a feeder route. The Madison (MAD) vor feeder route is a 14.3nm segment – notice it is an IAF. The Hartford (HFD) vor feeder route is only a 3.4nm segment – notice it is not an IAF, but leads to the LOMIS fix which is an IAF, which is followed by the holding pattern where there is room for the altitude change. That appears to compare exactly to the DPA feeder route to LYLLE segment (2.2nm) of the KDPA ILS or LOC RWY 10 approach, which is also not long enough to permit the required altitude change.
    https://www.faa.gov/documentLibrary/media/Order/FAA_Order_8260.3C.pdf page 2-19.

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