KCFO RNAV 35 - Confusing NA

[Michael Porowski]

I am an IFR student in Denver; I often fly approaches at KAPA.

I am confused by the NA note on RNAV 35 shown in the plan view area that says "Procedure NA for arrivals on FQF VORTAC airway radials 078 CW 220." I understand this to mean the approach is NA if arriving on an airway within radials 078 clockwise to 220. But why? I can't fathom why this would be a problem in this airspace.

My CFII said this note actually means there is no procedure turn from these inbound radials. This makes more sense but the actual note on the plate says nothing about a PT. I'm not sure if my CFII is making up BS (it wouldn't be the first time).

If anyone knows this approach and why, I would love to hear the reason.

Thanks

 

[Jim Carpenter]

I don't recall what the actual TERPS limit is, but when arriving at FQF on those airways, the angle of required turn is deemed too steep.
This kind of notation is common to many approaches, regardless of the airspace.

 

[midlifeflyer]

No, that is not a "noPT" notation.

This is an extremely common note. All it means is what it literally says. The procedure as published is not authorized if you are using FQF as the transition and you are arriving there on these published airways. It does not prevent the use of the approach in any other way.

And yes, it is usually because of exceeding a maximum agle for RNAV transitions. BTW, big hint - if you have a question about something on an approach plate, particularly a transition, it can more often or not be answered by looking at the enroute chart.

Parenthetically, I'm always amazed that this common notation is so widely misunderstood. A few years ago I worked the AOPA PPS booth at Sun n Fun. Although most of the questions were about enforcement and BasicMed, a CFII asked me this one (different approach).



PS... Yes, I know the approach. I flew out of KAPA as pilot, CFI and eventually CFII, for 20 years

 

[midlifeflyer]

BTW, the max angle for RNAV transitions is 90 degrees. So even without accounting for how long the VOR has been recalibrated, we're talking 97 degrees for V160 and about 120 degrees for V 148.

 

[Larry in TN]

There is not enough protected airspace to make the turn inbound when arriving on the specified radials.

 

[RussR]

Mark and Jim are absolutely correct, it's angle of turn. The current limit is 90 degrees. Up until maybe 15 years ago it was 120 degrees, so if you do see one that is greater than 90, it probably just hasn't been redesigned since then.

My CFII said this note actually means there is no procedure turn from these inbound radials. This makes more sense but the actual note on the plate says nothing about a PT. I'm not sure if my CFII is making up BS (it wouldn't be the first time).

It does seem that most often when people misread this as "Procedure Turn NA", there is no PT depicted anyway - so it makes me wonder if they're really thinking through their answer.

I also wanted to add, if your CFII is routinely making up BS, it's probably time to find a new one. Being wrong is okay, we're all wrong at times. But making up stuff when you don't know the answer? That's not acceptable to me.

 

[TCABM]

As Mark said, the procedure is Not Authorized for arrivals as depicted. There’s an article in IFR Magazine discussing this exact restriction and some of the whys. Might be worthwhile to review the article with you CFII.

No-arrival sectors - IFR Magazine

What is it with arbitrary rules and aviation? Like how some security Ph.D. determined that a quart bag of three-ounce containers dont constitute a security threat but a single quart of Pepsi does. Maybe they think terrorists arent smart enough to pool their resources. Or maybe the TSA brass just...

www.ifr-magazine.com

 

[midlifeflyer]

The current limit is 90 degrees. Up until maybe 15 years ago it was 120 degrees, so if you do see one that is greater than 90, it probably just hasn't been redesigned since then.

Russ, isn't it still 120 for ground-based navaids? Or has it changed universally?

 

[RussR]

Russ, isn't it still 120 for ground-based navaids? Or has it changed universally?

You're correct, it is still (and has been for as long as I know) 120 degrees for conventional procedures.

There is some (not very satisfying) historical discussion in these ACF minutes from the issue being raised in 2014 by NBAA. (NBAA requested it be changed back to 120 degrees, but in the end it was kept at 90.)

https://www.faa.gov/sites/faa.gov/files/about/office_org/headquarters_offices/avs/Hist_14-01-315.pdf