My question is: WHEN can I leave the approach track/Final Approach Course to line up with the runway? IF, as in this case, the final track does not directly align with the RWY? For circling, as I learned in Catalina many moons ago, there is a 1.2NM limit "officially" that one is supposed to stay within for category A/B aircraft. But, I haven't been able to figure out where to find the answer to this question as it is not circling. I would imagine that I could "call" it circling if I had to and be safe at 1.2NM deviating from the 316 track.
The 1.2 (actually 1.3) doesn't apply in this case as it's not circling.
There isn't really any official easy to find guidance on when to start the turn. So we have to dig in a little bit.
In terms of protected airspace. RNAV approaches are not covered by the TERPS. RNAV approaches have FAA order 8260.58 governing their construction.
RNAV TERPS is a lot more complicated then regular TERPS in a lot of areas including this one. Note the protected airspace width for a LNAV RNAV approach is 0.6 NM on each side of the final.
How it done depends on the exact angular difference between the Final course and the runway course. In this case we have a 15 degree offset. So the RNAV TERPS says to do this:
For offset > 10 degrees and ≤ 20 degrees, the course must cross the runway
centerline extended at least 3000 ft prior to LTP (5200 ft maximum). (Offsets
> 15 degrees, CAT C/D minimum published visibility 1 SM, minimum HATh of
300 ft)
This of course makes no sense without any sort of context.
LTP is the landing threshold point, or the point on runway centerline at the beginning of the runway.
Or in other words when on the final approach course you must cross the runway centerline between 0.5 and ~0.9 NM from the runway. If that's the case you simply turn when aligned with the runway.
A quick look at the chart tells us that this approach does not meet that rule, so what gives...
There is another option:
Note: Where paragraphs 2.1.1a-d (PG Note: The first quote is paragraph 2.1.1c) cannot be attained or the final course does not
intersect the runway centerline or intersects the centerline more than 5200 ft from
LTP, and an operational advantage can be achieved, the final may be aligned to lie
laterally within 500 ft of the extended runway centerline at a point 3000 ft
outward from LTP.
For all intents the final cross the centerline at the LTP. So with a 15 degree offset at 3000ft (0.5 NM) we are 800' off the centerline when 3000' from the LTP. Hmm ok, that's weird...
So this approach isn't in compliance with the RNAV TERPS....
Well it ends up this approach was made in 2009, back where there was a different RNAV TERPS.
So let's look at the now outdated FAA order 8260.54A. Well the relevant part of this document is identical, once again meaning this approach isn't in compliance.
So now we go back into ancient history to order 8260.38A which was issued in 1995.
This order says the following about final approach alignment:
Straight-in. For a straight-in approach, the
alignment shall not exceed 15 degrees from the runway centerline
(RCL) extended. Optimum alignment is coincident with the RCL.
Where the alignment is 3 degrees or less from the RCL, the
optimum alignment is to the runway threshold. Where the
alignment exceeds 3 degrees from the RCL, the optimum alignment
is to a point 3,000 feet from runway threshold on the RCL. Where
operationally required, optional alignment is authorized to a
point between, and including, the runway threshold and a point
3,000 feet prior to the runway threshold on the RCL, provided
alignment is within 15 degrees of the RCL.
So there is your answer, this approach was made with now out of date criteria.
Note that in all cases no additional protection is given for the turn to the runway. You are only protected within 0.6 NM of the approach course.
TL;DR - The final approach course should intercept the runway centerline about 0.5 NM from the runway, turn at this point. Really old approaches (like this one) don't do that. Turn when you see the runway and won't hit anything.
