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Looking to do more IFR flights - a few questions


Chris DeGroat
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Hey folks, I’ve mostly done vfr flights on vatsim with the exception of one ifr, but I have a few questions, well two really. The first is even when using offline atc programs I’m always confused in when to descend. Is atc supposed to tell you when and clear you to an altitude? Or do you start your descent at the appropriate point based on aircraft performance?  Im assuming it’s the former as ifr is all very calculated to get everyone in safely. 
 

Second question is, sometimes when I load procedures in the fmc, it looks like a mess around the airport itself. What I mean is, some arrivals to approaches look like you fly directly over the airport to make a hairpin turn to join the ils, ect. For instance the SARGO3 in to kcvg. To do the ils rwy 9 it basically has me arrive from the south west, cross over the aiport to the north and loop back around.  Is this realistic? I attached the procedure from foreflight for reference. I have the basic idea and concept of ifr but want to have as much of an understanding as I can so I don’t get overwhelmed live on the network. 
 

Thanks!

 

-Chris

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You would be radar vectored before FIDEK to the approach, so you would never overfly the airport and do those weird turns. This is stated on the SARGO3 STAR.

About the descending... I'm not a VATsim/ATC expert - far from it - but you should request your descend to ATC and they will then clear you and give you an altitude to go to. Or they might contact you themselves and clear you.

Screenshot 2021-08-15 220727.png

Edited by Spender Vondel
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43 minutes ago, Chris DeGroat said:

Is atc supposed to tell you when and clear you to an altitude? Or do you start your descent at the appropriate point based on aircraft performance?  Im assuming it’s the former as ifr is all very calculated to get everyone in safely. 

It's a combination of the two.

IFR being IFR, you cannot just initiate your descent at will, ATC has to clear you. However, it is your responsibility as PIC to determine at what point you need to initiate your descent in order to get down in due time, and meet the restrictions on the arrival. Normally, the way this is done is that your FMC, or dispatch, or yourself, calculate the "top of descent" (TOD) point, which is the point from which you can make a comfortable descent within the desired parameters. Depending on your aircraft type, this point may be displayed on your nav display, or you make a note of it in your flight plan.

Now, normally one of three things happens:

  • Before reaching TOD, ATC clears you to descend immediately to a given flight level or altitude; this means you are expected to initiate your descent right now, at a typical rate of descent.
  • Before reaching TOD, ATC clears you to descend when ready ("WHEN READY DESCEND ..."); this means that from now on, you can initiate your descent whenever you deem appropriate, and you may descend (for now) down to the cleared altitude or level. Typically, you would now either maintain your current altitude until reaching TOD, and then descend as planned, or you may initiate an early descend, descending at a lower rate of descent. The descent clearance is sometimes amended with "LEVEL BY (waypoint)", which means they expect you to plan your descent such that you reach the cleared altitude at or before the given waypoint. If your aircraft has a FPA mode (Flight Path Angle) and a green arc, you can nail this precisely by tuning the descent angle such that the green arc meets the target waypoint (it also works with V/S, but you will have to make further adjustments as your ground speed changes).
  • ATC does not clear you by themselves before TOD. In this scenario, you should call them up and request a descent yourself, ideally a couple minutes before reaching TOD.

Either way, you cannot descend without clearance.

55 minutes ago, Chris DeGroat said:

Second question is, sometimes when I load procedures in the fmc, it looks like a mess around the airport itself. What I mean is, some arrivals to approaches look like you fly directly over the airport to make a hairpin turn to join the ils, ect.

Many of these procedures will not be flown entirely as published; instead, you will be radar vectored in a more efficient way. The full published procedures are typically only flown in case of lost communications, and they are designed such that pilots can navigate them by themselves, and to avoid potential conflicts with other traffic as much as possible. And quite often, the safest way of flying into an airport without radar guidance is to overfly the airport at a safe altitude, well above landing and departing traffic, fly out on a track that doesn't interfere with the approach path, descend, and then make a turn onto the final approach path. Overflying the airport first has the added advantage that you can look out the window to look at the situation at the airport, spot other traffic, etc. Having a published procedure in case of lost comms is also important so that ATC knows what they should expect you to do.

In this particular case however, the procedure explicitly contains a radar-vectored portion, shown as a dashed line. That line is pure speculation; all that the procedure says is that you should expect to be radar vectored prior to reaching AGEBE, and if not, to maintain heading 004. The most likely cause of action for ATC would be to give you two or three left-hand turns and then clear you for the ILS, but that's not something the chart tells you, and the dashed line is just your FMS making guesses in order to calculate things like descent paths and fuel consumption.

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Thanks everyone!  This makes perfect sense now. Using offline atc programs obviously doesn’t account for a lot of this so things get confusing really fast. Probably should have paid more attention to the arrival chart itself which pretty much spelt that all out… lol whoops.  I’ll have to give this a whirl tonight. 

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No matter how much you think you know about IFR flying in a single-pilot environment, coming from that to VATSIM is a huge learning curve.  Keep asking great questions but don't get discouraged if, despite all your prep, you get online and something unexpected happens.  Best of luck and have fun!

Cheers,

-R.

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1 hour ago, Robert Shearman Jr said:

No matter how much you think you know about IFR flying in a single-pilot environment, coming from that to VATSIM is a huge learning curve.  Keep asking great questions but don't get discouraged if, despite all your prep, you get online and something unexpected happens.  Best of luck and have fun!

Yep - one thing I've learned from having my license in real life is every flight is a learning experience and something new, no matter how many times you go up.  Looking to get start my instrument rating before the years up so I'm hoping this gives me a decent overview of things.  Thanks for all the tips!

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