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While interpreting an RKPS(airport located in South Korea) LOC DME 06L, I found it somewhat confusing.

RKPS LOC DME Rwy 06L

As you see, the initial action of the missed approach is climbing via heading 063 to GIDOO.

I can understand without any doubt if the chart states that I have to maintain track 063 rather than heading 063. I'm flying in C172, so the wind correction angle for maintaining track 063 will be big if the wind exists. But, if I maintain heading 063 as defined in the chart, I will not be able to reach GIDOO which might be determined by DME distance plus Radial from VOR or Localizer.

I tried to find GIDOO in other charts, but I couldn't.

So, what I want to know is, what should I maintain while executing missed approach procedure?

As mentioned in the chart, maintaining heading? or maintaining track?

In my opinion, we can't get any radial information from the localizer(we can't get a reliable signal from the course other than preselected final approach course), so I have to maintain heading 063 then when I reach 2 DME from ISAM, turn right heading 130.

Is it the correct action? or Do I need to maintain track 063? or.. Tracking back course localizer to GIDOO?

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3 Answers 3

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In my opinion, GIDOO is 2 DME from the ISAM localizer antenna while on a heading of 063 degrees. It's not the intersection of 2 DME and the localizer.

Much like the next segment of the missed approach procedure where you turn to a heading of 130 degrees and join the SAC VOR 100 degree radial, the point at which you actually intercept this radial will vary depending on the wind.

Fly the missed approach procedure as published.

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  • $\begingroup$ So.. you mean the fix GIDOO is determined by 2 DME from localizer and heading of 063? GIDOO will change as the wind changes and the type of airplane changes. Is it okay and common? Actually, in South Korea, the majority of operations are by commercial, big airplanes, so Korean aviation authorities take less care of general aviation. This makes us differ from the text stated in the chart and we just follow the plan view of the chart. In the question's chart, we have to maintain track 063 NOT heading 063 to exactly track the course depicted in the chart. $\endgroup$
    – moon
    Nov 23, 2021 at 4:18
  • $\begingroup$ The missed approach procedure could say fly rwy heading until 2 DME then turn right heading 130 to intercept... But if you elected to begin your missed approach procedure on a 3 or 4 mile final (for example) an error could be made if you looked at your DME and began your right turn 2 DME southwest instead of 2 DME northeast. Giving the point at which the right turn to 130 degrees begins a name (GIDOO) helps remove any potential situational/position awareness error while you are busy with flying/navigating etc. the procedure. (High task situation). $\endgroup$
    – 757toga
    Nov 23, 2021 at 4:21
  • $\begingroup$ So you mean the fix GIDOO is NOT a geographical fix, but only for situational awareness? In small airplanes in a heavy crosswind, as you know, the difference between heading and track is a maximum of 20 degrees in extreme conditions. So even I execute missed approach procedure after passing MAP, my GIDOO can be a lot different from the big airplane's GIDOO. $\endgroup$
    – moon
    Nov 23, 2021 at 4:25
  • $\begingroup$ @moon In my opinion, fly the missed approach procedure exactly as published. Heading 063 degrees until 2 DME northeast of ISAM (GIDOO). Then begin a right turn heading 130 degrees etc. $\endgroup$
    – 757toga
    Nov 23, 2021 at 4:25
  • $\begingroup$ I agree with you.. Thank you If the procedure wants to maintain just heading 063, it usually doesn't mention the exact name of the fix. Just like "maintain heading 063 until D2.0 ISAM" I was just curious about why the chart mentions the exact name of the fix. $\endgroup$
    – moon
    Nov 23, 2021 at 4:32
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It is true, a track will send you directly over GIDOO but the missed approach text says to fly a heading. It would take a strong wind to have any real effect on the offset from GIDOO when you cross it.

Most likely there are other aircraft on radar vectors and are being affected by the wind just like you would be so separation from an ATC standpoint is achieved.

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  • $\begingroup$ So... you mean I have to maintain heading NOT track? And if the separation is needed, the ATC will vector me to separate? $\endgroup$
    – moon
    Nov 23, 2021 at 2:38
  • $\begingroup$ Yes on both questions. $\endgroup$
    – wbeard52
    Nov 23, 2021 at 2:57
  • $\begingroup$ thanks for your answer :) $\endgroup$
    – moon
    Nov 23, 2021 at 4:15
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I will need a little bit more context and need to see the entire approach plate, but it appears GIDOO is defined 2 NM DME from the localizer antenna along the localizer back course (this assumes the final approach heading is 063° magnetic as well). We would need at least two navaids to locate and identify GIDOO. This can be accomplished with the localizer DME, either along with localizer back course, or along a radial of the Saechon VORTAC which intersects GIDOO at 2 DME ISAM.

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  • $\begingroup$ Other than the plan view depiction making it appear that GIDOO is fixed along the localizer at 2 DME northeast of the antenna the textual description identifies this point (GIDOO) as being a point in space, the location of which is 2 DME northeast of the localizer antenna while maintaing a heading of 063 degrees. The exact geographic position of GIDOO would change while maintaining a heading of 063 degrees when any crosswind is present. $\endgroup$
    – 757toga
    Nov 23, 2021 at 19:00

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