Sign in to follow this  
FLJeff337

Request Different Approach - ATC Expectations?

Recommended Posts

On a recent flight from KTPF-KTIX, and while on V533 just slightly west-northwest of KMCO, ATC gave me instruction to turn right to 080, descend and maintain 3000' and expect vectors for the RNAV Rwy09 approach.

The winds were out of the south, so after I made my turn and started my descent, I requested the RNAV Rwy18 approach instead. ATC then approved it, and told me to report CUTON (the intermediate fix); no additional vectors or altitudes were assigned.

My question is, was I supposed to fly direct to FORNI (the initial fix) or to CUTON (an intermediate fix)? In either case, the direct route would have me flying at 3000' just a couple miles north of KMCO, off the approach end of runways 17L/R and 18L/R (which, IRL, wouldn't seem too smart).

Furthermore, my filed routing had me taking V533 to the ORL VOR, then outbound to OVIDO (which is a transition for KTIX's RNAV Y Rwy18 approach). After receiving my initial instructions from ATC, should I have requested the alternate approach, disregarded ATC's vectors/descent instructions, and continued flying as I had filed, descending at my own discretion?

 

Thanks,

Jeff

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Hi Jeff,

I'll take a swing at this since nobody has chimed in yet.

Once you request a different approach from VoxATC, it won't provide vectoring or altitudes any longer. It's now up to you (and your GPS!) to do these. Requesting different 'types' of approaches also cause VoxATC to require different responses, eg. asking for a VOR approach will trigger VoxATC to ask when your base turn is complete, and when you are beacon outbound, etc.  Requesting an RNAV approach will only require 2 replies, first will be the IF (Intermediate Fix) and then the FAF (Final Approach Fix).  After you respond to the latter, you will then be handed off to either the tower (if airport has one) or to the advisory frequency (CTAF).

Now, more specifically, KTIX RNAV(Z)18.  Looking at the approach plate, I see that FORNI is a transition, therefore shown as an IAF (Initial Approach Fix). Now, I don't know if the airport you are using is coded correctly, but, assuming it is, do you see the FORNI transition on your GPS?  If you do, then what you would do is navigate to FORNI, at or above 1600', then turn right to 137 to CUTON, at or above 1600', report CUTON, then VoxATC would ask you to report POPHY, the FAF.  Once you do that, you should be told to switch to Tower at 118.9.

Also, you seem to be mixing the 2 RNAV18 approaches, Y and Z.  I don't know which one is coded in the airport you're using, but you need to pick only one.  I don't believe that FSX/P3D allows more than one type of approach per runway.  Maybe someone with more knowledge about this will add their insight.

Hope this helps a little

Regards,

Jay

Share this post


Link to post
Share on other sites

Jay,

A couple days after my initial flight, I flew it again (with the same flight plan and weather as before) in order to further investigate Vox's behavior/logic.

This time, after receiving my initial approach instructions, instead of immediately complying with them (by turning to the assigned heading and starting my descent), I first requested the alternate approach (while maintaining my heading and altitude). After being told to report CUTON (the IF), I added FORNI into my GTN flight plan (after OVIDO), and continued to fly as filed (starting my descent at my own discretion). I reached FORNI at the published altitude, and continued to fly the RNAV(GPS) Z Rwy 18 approach without problem.

My initial question had more to do with Vox's "hands-off" approach once they approved my request for a different approach. Since I was expecting amended instructions given the new approach (either assignment of different heading, or perhaps a "proceed direct to..." instruction), I wasn't sure if I was still supposed to comply with their initial heading/altitude assignment, or if I was free to navigate to the start of the approach as I saw fit (including starting my descent at the appropriate time).

Having flown this flight a second time, I now see that Vox expects you to proceed to the start of the approach on your own, and won't issue amended instructions despite approval of a different approach from the one initially assigned.

While I wish Vox didn't cut you completely loose once they approved your request (I'd have to think that RW ATC would issue amended instructions so you don't conflict with other traffic), I do prefer a hands-off approach over one in which ATC is overbearing with excessive, out-of-the-way vectoring and descent clearances that start way too late (ala default ATC).

Regarding the two different RNAV Rwy18 approaches ("Y" and "Z"), I assumed I would be flying the RNAV Y approach (since my last waypoint before KTIX was OVIDO, which is a transition of the "Y" approach). However, when Vox told me to report CUTON, I realized they had assigned me the "Z" approach instead (even though it wasn't explicitly identified by Vox as such), and that's when I added FORNI (the IAF for the "Z" approach) into my GPS (just after OVIDO), and loaded the "Z" approach into the GTN (which is Flight1's GTN 650, with AIRAC 1803).

To answer your question about FSX/P3D recognizing multiple GPS approaches for the same runway, I added both the "Y" and "Z" approaches to KTIX using ADE (including the transitions), and it does appear that default ATC recognizes both (they're listed as "RNAV Z" and "RNAV Y" under the available options when you request a different approach ).

I can only assume that Vox would recognize both approaches as well (assuming it reads and utilizes the data included in the sim, including airport data),
although it doesn't appear you can request one over the other using Vox.

Thanks for taking the time to reply,

Jeff

 

Share this post


Link to post
Share on other sites

Jeff,

Just to follow-up on some points you made.  Once you are approved for your approach request you are on your own as far as vectoring and altitude.  You are expected to fly the approach as published, until you report the FAF.  At that point you're told to switch to either tower or CTAF freq, where you will be given clearance to land.  Oh, something I just remembered, if your approach request is met with 'unable at this time' then just wait until you are given a new squawk code and then make the request again.  You will get approved this time.  Don't have any clue why.

About the multiple approaches issue.  VoxATC will only display the approaches that are coded in the AFCAD.  I have also tried to add, let's say, a Y and Z RNAV to the same runway using ADE.  While I didn't know the default ATC would recognize both (haven't looked at default ATC in many years) I did know that VoxATC won't.  My own workaround is this; if it's really necessary to have a Y and Z, for example at KEWR there's an RNAV X and Y into runway 29 that are completely different, and I use both, then I use RNAV for one and add a GPS approach for the other.  I also add the proper X or Y to the header which helps me remember what I did, and which one is which.  Does that make any sense?

Jay

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this