Which do we file, /I /A /W /P, it's an age old debate.

[Ken Doyen]

We have had this conversation several times in the community.  We fly older aircraft with INS capability but only use it at cruise.  We use /A /W /P on the SID & STAR portion cuz it's much easier to keep track of where we are & make adjustments when given instructions.  If we file /I, is it implied that we can/will use a combination of the different equipment types?  Many seem to just file /W, but, I am new to /I & just assumed we should file /I.  In either case, we don't seem to get yelled at, it appears to controllers we are flying the correct procedures.  Does it make a difference to controllers which equipment suffix we file in this case? 

[Nicholas Cavacini]

You would file based on your overall capability. The expectation is that you're able to perform at the listed capability throughout flight.

[Ken Doyen]

1 minute ago, Nicholas Cavacini said:

You would file based on your overall capability. The expectation is that you're able to perform at the listed capability throughout flight.

So it should be /I if using it at any point in our flight?  The scary part for us is if/when given a direct to, the display in the cockpit is numbered, it doesn't list the abbreviation like GPS.  What I & many others do is take a screenshot of the nav log & number all the way points.  Eg, I'm told to fly direct JFK VOR & it is the #10 slot in my DED.  If I'm at my # 8 way point I need to look at my numbered screenshot to figure out which # JFK is.  It is overwhelming flying solo.   I think that's why most prefer to file /W instead.  I find INS very interesting & fun in it's own way, but, given the potential for screw ups, would you recommend we not file /I?  

[Nicholas Cavacini]

It is certainly more of a challenge flying INS navigation, but remember in the case of a VOR, you can certainly use raw data and track the VOR to go direct to (most INS systems rely on VORs for periodic recalibration/verification anyways). That being said, when asked to go direct a navaid, you generally have a short period of time to make the change. That time frame is very situation dependent but you're not expected to instantaneously make the turn. If you are having issues, communicate with ATC.

[Ken Doyen]

Ok, will do.  Thanks. 💓

[Brad Littlejohn]

Let me answer this question with another question: How realistic do you want to be?

Obviously, you can file any of those equipment suffixes and be perfectly fine. However, what will come into contention is when you het the floor for RVSM. For most parts of the world, separation standards for RVSM would start at FL290 and continue up to FL410 (for dRVSM in the USA, it is FL290 to FL410 inclusive). Outside of the US (and quite possibly Canada) you'd be okay with filing any applicable altitude without encountering any vertical separation issues. However, if you filed this in the US, you'd be subject to the older separation standards we had, which was 2000ft separation for each direction of flight. So FL290 = east, FL310 = west, FL330 = east, FL350 = west, etc, up to FL410, where it is always 2000ft separation.

You can see the issue if you filed /I or /G and FL310. With another aircraft filing /L, /W or /Z (read: RVSM capable), you'd be at the same altitude for the opposite direction of flight... not a good thing. So when it comes to non-RVSM capable equipment, be aware of the altitude you're filing, as you'll run into issues when hitting RVSM altitudes.

BL.

 

[Robert Shearman Jr]

I believe the real-world custom is to file the highest level your aircraft is capable of and the crew is certified for, even if you don't intend to use it.

On VATSIM, there are goofballs like myself who will file a lower level of equipment capability because I'm "simulating that the plane doesn't have such-and-such gadget," etcetera.

To Nicholas's point -- yes, indeed, when you're given a direct-to somewhere, it is often a good idea to use heading mode to get you pointed in roughly the right direction; then, as immediately as possible, get your NAV equipment caught up so you can fine-tune that direction the last handful of degrees to your proper "direct" -- if that makes any sense.

[Ken Doyen]

2 minutes ago, Brad Littlejohn said:

Let me answer this question with another question: How realistic do you want to be?

Obviously, you can file any of those equipment suffixes and be perfectly fine. However, what will come into contention is when you het the floor for RVSM. For most parts of the world, separation standards for RVSM would start at FL290 and continue up to FL410 (for dRVSM in the USA, it is FL290 to FL410 inclusive). Outside of the US (and quite possibly Canada) you'd be okay with filing any applicable altitude without encountering any vertical separation issues. However, if you filed this in the US, you'd be subject to the older separation standards we had, which was 2000ft separation for each direction of flight. So FL290 = east, FL310 = west, FL330 = east, FL350 = west, etc, up to FL410, where it is always 2000ft separation.

You can see the issue if you filed /I or /G and FL310. With another aircraft filing /L, /W or /Z (read: RVSM capable), you'd be at the same altitude for the opposite direction of flight... not a good thing. So when it comes to non-RVSM capable equipment, be aware of the altitude you're filing, as you'll run into issues when hitting RVSM altitudes.

BL.

 

Me personally, I stay at FL270 or FL280 cuz that's what I'm used to flying at.  I have no reason to go higher the way I fly so RVSM is a non issue for me, but, good point.

[Ken Doyen]

3 minutes ago, Robert Shearman Jr said:

I believe the real-world custom is to file the highest level your aircraft is capable of and the crew is certified for, even if you don't intend to use it.

On VATSIM, there are goofballs like myself who will file a lower level of equipment capability because I'm "simulating that the plane doesn't have such-and-such gadget," etcetera.

To Nicholas's point -- yes, indeed, when you're given a direct-to somewhere, it is often a good idea to use heading mode to get you pointed in roughly the right direction; then, as immediately as possible, get your NAV equipment caught up so you can fine-tune that direction the last handful of degrees to your proper "direct" -- if that makes any sense.

That's kind of what I was wondering too.  I can file /I /A /W /P all on one plane.  As I've been told in the past, we might have it but not required to use it.  So as Nick said, file the overall capability.  That would be /I.  But I've done some flights /P the whole way,  I don't think that's doing anything wrong as I never programmed the INS in that flight.  That's why I worded it as "at any point in flight" if I'm making any sense.