RNAV Approach Clearance

[yup]

When am I allowed to clear an aircraft for an RNAV approach? For this question I don't want to give them vectors, I want them to fly the procedure on their own.

Let's look 4–8–4 Approach Clearance Procedures. According to subpara (a)5 I can clear them for the approach if I send them to a fix at least 3NM outside the FAF at an intercept angle of no more than 30 degrees. Okay.

But say they're inbound at a greater angle than that. Paragraph (d) says I can clear them for the approach if they're direct to the IAF as long as a procedure turn, hold-in-lieu, or arrival holding pattern is depicted and the pilot will execute the procedure. Great!

Oh, but look at paragraph (h) with its RNAV APPLICATION banner. Subpara (h)1 says they have to have no more than a 90º intercept to the FAF before I can clear them. So… I should give them direct the FAF, tell them to "advise inbound," and withhold the approach clearance until then. Seems strange, but RNAV approaches aren't based on approach aids from the ground so they might be more restrictive (like when you're vectoring for an approach, the exceptions allowing intercepts within two miles of the gate don't apply to RNAV approaches). I can live with that.

But wait! There's more! Look at the example at the bottom of the paragraph. The first example below figure 4–8–4 shows Aircraft #2 being cleared direct CENTR, maintain at or above, cleared approach despite the greater-than-90º intercept! They explain that Aircraft #2 will execute the hold-in-lieu so it's okay. I would buy that explanation except that subpara (h)1 doesn't say anything about it being kosher if there's a hold, it says you have to have no more than 90º, full stop.

So what gives?

 

[32andBelow]

The answer is going to change based on the specific Approach. But we usually clear them over an IAF with less than a 90 degree turn on. But things change based on if there’s a bold hold in lieu of. Or if it’s a t approach. Or if there’s transitions to the IAF

 

[yup]

But things change based on if there’s a bold hold in lieu of.

Assume there is a bold hold-in-lieu at a fix that is marked IF/IAF. If it was an ILS or VOR approach I would say "direct the fix" and "cleared the approach" in the same breath and move on, knowing the pilot would fly the procedure. Subpara (h)1 makes it seem like that isn't allowed for an RNAV approach, but then in the example they do do it that way.

 

[MJ]

When am I allowed to clear an aircraft for an RNAV approach? For this question I don't want to give them vectors, I want them to fly the procedure on their own.

Let's look 4–8–4 Approach Clearance Procedures. According to subpara (a)5 I can clear them for the approach if I send them to a fix at least 3NM outside the FAF at an intercept angle of no more than 30 degrees. Okay.

But say they're inbound at a greater angle than that. Paragraph (d) says I can clear them for the approach if they're direct to the IAF as long as a procedure turn, hold-in-lieu, or arrival holding pattern is depicted and the pilot will execute the procedure. Great!

Oh, but look at paragraph (h) with its RNAV APPLICATION banner. Subpara (h)1 says they have to have no more than a 90º intercept to the FAF before I can clear them. So… I should give them direct the FAF, tell them to "advise inbound," and withhold the approach clearance until then. Seems strange, but RNAV approaches aren't based on approach aids from the ground so they might be more restrictive (like when you're vectoring for an approach, the exceptions allowing intercepts within two miles of the gate don't apply to RNAV approaches). I can live with that.

But wait! There's more! Look at the example at the bottom of the paragraph. The first example below figure 4–8–4 shows Aircraft #2 being cleared direct CENTR, maintain at or above, cleared approach despite the greater-than-90º intercept! They explain that Aircraft #2 will execute the hold-in-lieu so it's okay. I would buy that explanation except that subpara (h)1 doesn't say anything about it being kosher if there's a hold, it says you have to have no more than 90º, full stop.

So what gives?

Not sure if you typo'd, but h(1) is

Established on a heading or course direct to the IAF at an intercept angle not greater than 90 degrees and is assigned an altitude in accordance with b2. Radar monitoring is required to the IAF for RNAV (RNP) approaches when no hold-in-lieu of procedure turn is executed.

Can't ever clear someone to the FAF (para c)

#1 can be cleared to CENTR straight-in or to LEFTT. #2 can be cleared to LEFTT or to CENTER with the procedure turn. If a TAA exists, it defines where you can clear an A/C to a fix, so that's pretty straight forward. If you were to clear #1 to SHANN, assuming its more than 3NM from BIRDD, it would have to be the standard 30° intercept from a(5), otherwise you can't use SHANN. LEFFT and RIGHT would both have the 90° requirement .
I think you understand everything correctly, so maybe just overthinking it. a(5) is the generalized rule, and h is specific to rnav's, so there's no conflict or ambiguity between them in my opinion.

 

[the inquirer]

You can’t clear an aircraft to a FAF. An IF or IAF only and usually those will have a procedure turn.

 

[yup]

I think you understand everything correctly, so maybe just overthinking it. a(5) is the generalized rule, and h is specific to rnav's, so there's no conflict or ambiguity between them in my opinion.

Assume no TAA. You say (and the example shows) #2 going direct CENTR for the course reversal procedure, but (h)1 does not allow that for RNAV approaches, at least the way I read it. Can you explain your argument otherwise? When it says Established on a heading or course direct to the IAF at an intercept angle not greater than 90 degrees how can you get out of that? Obviously because they're going to execute the procedure to turn themselves around, but the way it's worded that doesn't seem to matter. Seems like ambiguity if they did mean to allow it.

Not sure if you typo'd

Affirm, typo, meant "should I clear them to the IAF and wait until they report inbound to issue approach clearance?"

You can’t clear an aircraft to a FAF. An IF or IAF only and usually those will have a procedure turn.

My typo. The way I read it I can clear someone direct the IAF for the procedure turn on a regular approach and issue the approach clearance at the same time, but (h)1 disallows that for RNAV approaches because they have to intercept no greater than 90°. Unless they mean specifically for a straight-in approach, but they don't say that!

To be clear, I'm of the opinion that I CAN issue direct the fix and cleared the approach all at once, because duh, that's the point of the course reversal procedure. But I can't justify that except by looking at the example, which makes me uncomfortable.

 

[32andBelow]

Assume there is a bold hold-in-lieu at a fix that is marked IF/IAF. If it was an ILS or VOR approach I would say "direct the fix" and "cleared the approach" in the same breath and move on, knowing the pilot would fly the procedure. Subpara (h)1 makes it seem like that isn't allowed for an RNAV approach, but then in the example they do do it that way.

If it’s bold they have to do the turn. If the turn on is less than 90 degrees you can say cleared straight in and they won’t do the turn.

 

[GulfCharlie]

If it’s bold they have to do the turn. If the turn on is less than 90 degrees you can say cleared straight in and they won’t do the turn.

You clearly have not worked military shooting RNAV's, they still do the turn even if you cleared state "cleared straight in" XD

 

[32andBelow]

You clearly have not worked military shooting RNAV's, they still do the turn even if you cleared state "cleared straight in" XD

Ha! That can be very bad if there’s a sequence!