Stephen Loeffler (SoCal TRACON)
(Public Guest)
07/23/17 09:34 PM
30/90 degree intercept?

So we all feel stumped sometimes and it's always good to go back and review the rules. But this time I feel stuck. I am training a new guy, and he gives an aircraft direct to an IF on an ILS and clears them for the ILS. I ask him about the intercept angle (it was about 60 degrees), and he says he can do it because it's within 90 degrees of the final approach course. I was always taught 20/30 degrees for normal approaches, and 90 degrees for RNAV approaches.

So we go back, review the 7110, and he agrees he should not have given the aircraft that turn because it was only an IF, but still believes he can give the aircraft up to a 90 degree turn to a straight in final if it's at the IAF.

Paragraph a section 4 and 5:

4. Where adequate radar coverage exists, radar facilities may vector aircraft to the final approach course in accordance with Paragraph 5-9-1, Vectors to Final Approach Course, and Paragraph 5-9-2, Final Approach Course Interception.
5. Where adequate radar coverage exists, radar facilities may clear an aircraft to any fix 3 NM or more prior to the FAF, along the final approach course, at an intercept angle not greater than 30 degrees.

Paragraph e:

e. If a procedure turn, hold-in-lieu of procedure turn, or arrival holding pattern is depicted and the angle of intercept is 90 degrees or less, the aircraft must be instructed to conduct a straight-in approach if ATC does not want the pilot to execute a procedure turn or hold-in-lieu of procedure turn. (See FIG 4-8-3)

EXAMPLE: Aircraft 1 can be cleared direct to XYZ VORTAC, or
SECND because the intercept angle is 90 degrees or less.

For our example, I will use a local ILS we use a lot.

KPOC ILS plate (sorry, couldn't get an image of it)

The trainee believes you can be east of PDZ and clear the aircraft direct to LIZZE for a straight in ILS, no procedure turn. To me, this doesn't seem right, and goes against what I have read elsewhere (and earlier in this chapter!)

5-9-2 Paragraph a

a. Assign headings that will permit final approach course interception on a track that does not exceed the interception angles specified in TBL 5−9−1.

I wasn't able to find an image of table 5-9-1, but it basically says, either 20/30 degree intercept angle based on how far you are from the final approach gate.

I feel like the diagram in 4-8-3 is misleading, or I am wrong in thinking that the intercepts for an ILS need to be 20-30 degrees. Hopefully I can pull some of you out of the shadows to help me understand what the 7110 is trying to say. Of course, I can always provide more information if needed.


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