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I'm a flight sim user practicing instrument navigation with a short and apparently simple flight, SBMG to SBLO (South America). The distance between the two airports is 49.5 nautical miles (the simulator tells me). My simulator is X-Plane 11. The aircraft is the Cessna 172.

I've flown the mentioned flight a couple of times, but I'm afraid I am making mistakes. There are a couple of questions I'd like to make.

Let's start with this SBMG SID chart (these charts come from AISWEB). The path with red dots is the one I'm following.

SBMG SID chart

(1) You see 096 > on the first 3 nautical miles? Does it mean I should track course 096 on the LON VOR right after takeoff, or is it just the heading I should be on for the first 3 nautical miles? You see, I'm having trouble figuring out what is the reference navigation aid for these headings/radials.

(2) After passing MG123, I start to track the 100 radial on the LON VOR for 47 nautical miles. After 47 miles I switch to the approach chart. Is that correct?


The next chart is a IAC for SBLO. It has a VOR/DME arc.

SBLO IAC chart

(3) I am still tracking 100 towards LON, but the nearest entry point for the arc is 090. After 47 nautical miles, I am too close to SBLO to change my course, and it's time to enter the arc already. I feel I missed something.

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    $\begingroup$ Well, for one thing that MG123 waypoint is an RNAV waypoint, you cannot fly that route using conventional VOR/DMEs you would have in a Cessna.You need to be at least B-RNAV capable, then track 096 to MG123 followed by 100 to LON (which just so happens to be a VOR but does not need to) $\endgroup$ – Radu094 Feb 13 at 17:10
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    $\begingroup$ The VOR chart is indeed a conventional one, but it does not match your route. You either need to find a transition of some sort, radar vectors, or self-position (using RNAV) to Ceila which is your Initial Fix $\endgroup$ – Radu094 Feb 13 at 17:12
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    $\begingroup$ @Radu094 - Celia is marked IF (Intermediate Fix). If it were an Initial Approach Fix, it would be marked either IAF or IF/IAF. $\endgroup$ – Dean F. Feb 14 at 1:32
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    $\begingroup$ Thanks for the clarifications. It seems I have a lot to learn before attempting these procedures. Do you recommend any specific material that covers instrument navigation thoroughly? $\endgroup$ – crimson_king Feb 14 at 2:17
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    $\begingroup$ Just to clarify, it is usually unwise to join the Approach on the Intermediate leg unless you are being radar vectored by ATC due to the difference in altitude between the MSA and the crossing altitudes for the FAF. As far as thorough material... $\endgroup$ – Dean F. Feb 14 at 3:41
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Interesting academic exercise crimson_king. I don’t think you would get cleared for or use this SID/IAP combo. The airports are too close together. You are basically using your destination airport’s NavAid as the beginning/start of your departure. You will overfly the airport before you get to the VOR that starts the procedure. Then, you would have to backtrack out to the arc, using LON as your IAF.

The plate that you referenced is just an instruction on how to get to the start of your departure. There is probably a textual ODP to go with it. If you were in IMC, you would remain under radar vectors and ATC control the entire time. They would probably give you instructions like: Fly runway heading climb and maintain 5000 radar vectors direct D270L cleared the VOR Z Runway 13. This is of course abbreviated since you would have a switch of ATC from tower to approach.

Based on the information provided, For the purposes of simming, your best bet is to:

  1. Take off from the runway of predominant wind.

  2. Remain in the traffic pattern and climb over the airport.

  3. Climb until you are at 5000 feet or more. The reason for this is that the only altitude information I see on the plate are the Minimum Sector Altitude and the Maximum Elevation Figures.

  4. Fly direct to MG123 using RNAV/GPS.

  5. Switch to VLOC/VOR mode

  6. Fly direct to D270L.

  7. Begin your IAP

    A second option is to just fly direct to LON using your Nav radio by the shortest route possible. Use MG123 as a fly over reference point. Maintain full throttle at Vx until 5000 feet. Once you are within 12 miles DME of LON. Start your descent down to 4100 feet. Join the arc wherever you happen to enter.

Celia is not marked as an IF/IAF. So, I would avoid going directly there. It would be a perfectly good option if you were being radar vectored and cleared there by ATC.

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  • $\begingroup$ Thank you for this answer. I will study the information you gave me once I catch up on the required missing pieces of knowledge. It's been a couple of years since my last simulator flight. I'm just a programmer who's enthusiastic about aviation! $\endgroup$ – crimson_king Feb 14 at 2:35
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    $\begingroup$ @crimson_king - No problem. You might start with US FAA charts and plates first. I am biased for them since they are what I first learned. They seemed to contain more explicit detail in a clearer format than the charts you linked. You can get them free from many online sources like skyvector.com and faa.gov/air_traffic/flight_info/aeronav/digital_products $\endgroup$ – Dean F. Feb 14 at 3:05

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