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SID, STAR, NAV by example


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Hi countrymen.

Bear with me, I might explain like a fool. I have been practicing my IFR stuff offline, because I am nervous to go on Vatsim just yet. Last night I started working my way through SID's and STAR's and it is probably worth mentioning that I fly smaller aircraft (like MU2). I don't use the GPS much, so I rely alot on everything else, and since it doesn't have a FMS, Im totally manual here.

 

Looking at FACT's charts

http://www.caa.co.za/resource%20center/Charts/AERONAUTICAL%20CHARTS/C/FACT_CAPE%20TOWN%20INTERNATIONAL/

 

I decide to take off, fly a SID, then do some random flying and come back and join a STAR. I left with SID INSOM1A, and this is where I would like to explain how I did it in my self-figured-out manner, and I would like to know from you how far I am off...

 

it says climb to fl090 and keep on rwy heading for 3nm from the CTV vor. So once on the runway, I set my heading bug to 345(the layout chart says rwy 01 is 345). I then proceeded to enter my CTV frequency into NAV. I set the autopilot alt to 9000 and altimeter to qnh. I started rolling, and once airborne around 500 i retracted flaps, lifted gear and activated the altitude and heading hold to aim for runway heading and fl090.

At 3DME (interpreting this as nm from CTV as per the DME), I set heading bug to 330. At this point I already set my VOR needle to radial 354. once my aircraft was doing the 330 course, I enabled NAV hold, while it was busy intercepting radial 354.Somewhere around this point I crossed 7500' so i set pressure to 1013...

 

Now the chart says, at 8dme turn left direct imson... I got confused. What does "direct" mean on my gps-less ifr?

The best i could do (since I was offline and no atc, I imitated an unmanned field), was to notice that IMSOM on the chart said R-297/30d CTV. I interpreted that by setting my VOR to radial 297, and hoping that it woudl intercept it at some point, but I know this is cowboy and can't be right...

 

So what should I do there, how do I interpret that 'direct' part?

I guess what it comes down to is, all those SID and STAR points (liek IMSOM) are imaginery points in space, no navaids to get there, so upon returning to a STAR, how do you get to that point? Should I stop concentrating on navaids like vors and ndb's and focus on GPS rather?

And when I get to IMSOM I am free, correct? i can do my thing, stick to my FP and come back and join a STAR in pretty much the same manner as I explained above?

 

 

Am I doing this ok, don't be gentle, let me know.

 

Thanks!

Marlon

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Now the chart says, at 8dme turn left direct imson... I got confused. What does "direct" mean on my gps-less ifr?

The best i could do (since I was offline and no atc, I imitated an unmanned field), was to notice that IMSOM on the chart said R-297/30d CTV. I interpreted that by setting my VOR to radial 297, and hoping that it woudl intercept it at some point, but I know this is cowboy and can't be right...

 

So what should I do there, how do I interpret that 'direct' part?

I guess what it comes down to is, all those SID and STAR points (liek IMSOM) are imaginery points in space, no navaids to get there, so upon returning to a STAR, how do you get to that point? Should I stop concentrating on navaids like vors and ndb's and focus on GPS rather?

And when I get to IMSOM I am free, correct? i can do my thing, stick to my FP and come back and join a STAR in pretty much the same manner as I explained above?

 

 

Am I doing this ok, don't be gentle, let me know.

 

Thanks!

Marlon

 

From the CTV 8 mile fix, where you turn left to IMSOM, I do not see a way to navigate to it using conventional navigation. IMSOM is on the CTV 297 radial at 30 DME according to the text under the fix, but until you intercept the 297 radial, you're just free flying. I guess depart the 8DME fix and turn left to a heading less than 297, such as 280 or 270. The 297 radial will eventually center up and you can navigate to IMSOM from there. Until you intercept that radial though, you're subject to wind drift since you don't know your exact path over the ground with a given heading.

 

[Mod - Happy Thoughts]uming this SID is not meant to only be flown with GPS/RNAV capable aircraft, then it must not matter that you spend this time without positive navigational control. This is only flown while under ATC radar surveillance, so that may be a reason your not always pinned to a specific radial or track. It appears the main point of this procedure is to get you to avoid that terrain peak and obstruction just south of Ysterplaat. After crossing the 8DME fix and turning left to try and track to IMSOM, the idea is that you shouldn't get unsafely close to that peak/obstruction because you'll intercept the CTV 297 radial first. If the wind is strong and your intercept heading insufficient, the worst you'll do is take too long to intercept the 297R or maybe even track away from it to the North, where there are no obstructions.

 

This is just my guess, I am not actually well versed in African procedures.

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