How to Request to Start an Approach at the Intermediate Fix (IF)

February 25th, 2014 by Max Trescott
Requesting to be cleared "Direct to" the IF can result in a hairpin turn that's not permitted by the AIM.

Requesting to be cleared “Direct to” the IF can result in a hairpin turn that’s not permitted by the AIM.

Instrument pilots know that there are two ways to start an instrument approach: they can get vectors or fly direct to an initial approach fix (IAF). Last month, I wrote about the “new” third way to start an approach, by flying to the intermediate fix (IF). This month I planned to write about the challenges in requesting to start an approach at an IF. Coincidentally, the day this article was due, the problem I planned to describe occurred…again.

I added quotes to “new” because, while this third method has been described in section 5-4-7(i) of the Aeronautical Information Manual (AIM) since 2006, I expect it will take many years before this information fully permeates the pilot and controller populations. Why so long? Partly because old habits in aviation die slowly and because standard IFR phraseology is confusing when applied to starting at an IF.

The confusion is not unlike the language issues that led to “Position and hold” being changed to “Line up and wait,” a change I enthusiastically supported. Countless times I’ve been in the cockpit with a pilot who confused “Position and hold” with “Hold short,” presumably because they both contained the word “hold.” In this case, potential confusion exists with the words “vectors” and “direct to,” when used to request to start an approach at an IF.

In September 2012, I exchanged several emails about this problem with a friend who is a supervisor at the Northern California TRACON. In my first email, I wrote in part,

“In my books, I tell pilots that there are three ways to fly an instrument approach:
1. vectors,
2. own navigation (or pilot navigation) to an IAF, and
3. a third method, which appeared in the Aeronautical Information Manual beginning in 2006 that allows pilots to start at an IF under certain circumstances (see extract from my G1000 Book below).

“We have short, well understood names that pilots use to ask controllers for the first two methods. But I’m not aware of a convenient name for pilots to use when requesting this third method. Are there quick, easy names that controllers use to describe this third method? Or should we be inventing a new name for it and promoting it among the aviation community?”

Why the need for a “quick, easy name?” Because for years, I’d sometimes had to clarify my request to start at an IF by adding that I’d like “to be vectored to a point from which you can clear me direct to DOCAL with a turn of less than 90 degrees.” That’s a mouthful and an inefficient use of radio time at a busy TRACON.

The reply from my supervisor friend was that the consensus at the facility was that a pilot should name the approach and ask to start at the name of the IF. In the case of the GPS 31 approach at Palo Alto, a pilot would ask to “start the approach at DOCAL,” Alternatively, you might consider requesting “to start the approach at the Intermediate Fix,” which should trigger the controller to remember the 90 degree turn rule.

Potential Confusion in Phraseology
Using the words “vectors” or “direct to,” works great when a pilot is requesting to start an approach with vectors or at an IAF. But they can be confusing when used to start an approach at an IF.

“Vectors” means you’ll be guided to join an approach at least several miles outside of the final approach fix (FAF). Requesting “vectors to DOCAL” could make sense, except that the JO 7110.65U tells controllers that when giving vectors, they are to turn pilots to within 30 degrees of the final approach course, not the 90 degrees permitted at an IF. So you don’t really want “vectors” to the IF.

If instead of asking to “start the approach at DOCAL” a pilot asks to be cleared “Direct to DOCAL,” controllers will sometimes take that literally and clear a pilot from their present position to the IF. But this can result in nearly a 180 degree turn at the IF, which isn’t permitted under 5-4-7. And that’s exactly what happened to me today. I had just crossed over Moffett Field and was essentially on a downwind leg to the approach. The controller asked whether we wanted vectors or to start the approach at DOCAL. I chose the latter and was immediately cleared “Direct to DOCAL.”

I’m not sure why the controller did that, though I’m guessing he was familiar with the 90 degree rule in 5-4-7. Shortly afterwards, I said “we’d like to continue on this heading until we can make a turn of less than 90 degrees at DOCAL,” to which he said “That will be fine.”

Why so casual? We weren’t IFR, but were doing a VFR practice approach, where separation standards are relaxed. Under those circumstances, I’ve seen controllers not require a turn of less than 90 degrees at an IF, a practice that may confuse pilots and controllers alike about the proper way to start an approach at an IF.

Get on the Same Page as the Controller
Regardless of how you request an approach, or how you are cleared to an approach, it’s important to be on the same page as the controller. If you have any doubt as to whether the controller and you have the same game plan in mind, request clarification. In the meantime, don’t hesitate to ask to “start the approach at the IF” if that’s how you would like to fly the approach.

Max Trescott

Max Trescott specializes in teaching in glass cockpit aircraft. He is best known for his Max Trescott's G1000 Glass Cockpit Handbook and Max Trescott's GPS and WAAS Instrument Flying Handbook. He formerly worked for Hewlett-Packard and now is a full-time flight instructor. He is the 2008 National CFI of the Year. Visit Max’s website.

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The opinions expressed by the bloggers do not reflect AOPA’s position on any topic.

  • James Taylor

    Having recently retired from a 47-year ATC career with FAA and DoD, I can tell you that today’s controllers are not thoroughly trained in instrument procedures, and what the pilots’ requirements are, the way we used to be. There are some very good ones, buy many that are like that one that said “that will be fine” when asked about the less-than-90 degree turn at DOCAL. A large percentage of controllers used to be pilots “in the old days.” Today, very few are or are even interested.

    Another example: Try asking a few of them about direct, parallel, and teardrop holding pattern entries, and see how many even know what you’re talking about.

  • Harold

    Turns of greater than 90 degrees from GPS waypoints to approach courses are common when you’re just practicing approaches under VFR, since the rules for handling VFR practice approaches are completely different. You can always do practice approaches under IFR if you’d like to. The response “That will be fine” is no different than “Proceed as requested,” which is exactly what I’d expect to hear from a controller if I requested a different vector while practicing approaches under VFR — except in Class C or B airspace, where a restated vector would normally be issued.

    My question: What exactly is the purpose of starting an approach from an IF? If you’re flying into an airport that is truly IMC, wouldn’t it be best to establish yourself on the approach earlier than the IF? “But what about vectors outside the FAF? Doesn’t that disprove your suggestion?” No, because vectors outside the FAF put you on a 30 degree or less intercept, making it much easier to join the approach. While I know there are exceptions to what I’m about to say, many IF step-down altitudes are lower than minimum vectoring altitudes (MVAs) surrounding the approach course. A pilot who requests to join an approach from the IF would have to maintain the MVA until established on the approach course. Thus, the pilot would begin the 90 degree turn onto final, at some point be considered established, and then would essentially have to dive down to rejoin the charted vertical profile. In IMC, this does not seem practical to me.

    That said, I know approaches are different throughout the U.S. The ones with which I’m familiar have IAFs placed at reasonable distances from the runway, negating any real benefit of joining from an IF. Those which don’t have radar service, which can enable a controller to provide vectors to join jist outside the FAF. I’m curious to know which approaches would incline a pilot to want to join from an IF.

    • DrZman

      “My question: What exactly is the purpose of starting an approach from an IF? If you’re flying into an airport that is truly IMC, wouldn’t it be best to establish yourself on the approach earlier than the IF? ”

      In the case of the PAO GPS 31 it would be inconvenient depending on the direction of your track. For example if I am coming from the SE going left or right to LICKE or SAPID would be considerably out of my way and I would gain nothing provided I was direct to DOCAL and I was given a 4400′ MSL crossing at DOCAL.

      There is also a comfort issue. Starting at either IAF puts you over some mountainous terrain which can be the origin of a lot of cumulus build up and turbulence. If you were on one of the V-airways on which the IAFs are located then, of course, it would make total sense to start there, but in my frequent trips to PAO from LA this is rare. Asking for an early direct-to DOCAL from a point in the central valley that allows for the crossing of mountains at their lowest is the most comfortable. For example, the low spot which is roughly a diagonal across San Louis Reservoir to South County then directo-to DOCAL is good. Coming up the Salinas Valley then asking for a direct-to DOCAL also is good.

      In any event, make sure you get a reasonable crossing altitude as should be the case on all approaches so that you do not have to do a slam dunk to get down.

  • Dean Winslow

    I’ve actually flown the GPS31 approach into PAO many times. The controllers I’ve dealt with seem to know the rules. When you’re on vectors from the north or east they usually vector you right over SJC to keep you out of the way of arriving and departing traffic
    then will clear you direct DOCAL.

  • Sam Shields

    I agree with the comments of James below. After retiring from a 25 year career in ATC, and still flying several times a week in the system, I can tell you that controllers don’t have a clue as to the pilot’s responsibilities or desires. Furthermore, very few of them understand their own requirements in regard to instrument approaches or why any of these requirements are even needed. Sadly, the 7110.65 Controller’s manual that I considered my “bible,” seems to be rarely consulted and of little importance in today’s ATC environment.

  • Max Trescott

    Harold, I think DrZman has it right…DOCAL almost always saves a pilot time versus going to an IAF for the GPS 31 PAO. No matter where you come from in the continental U.S., the SAPID IAF is out of the way, and over mountainous terrain (yes, it’s are reasonable place to start if you’re coming in from Hawaii!). The other IAF LICKE puts you on a leg that goes directly over the final approach corridor to San Jose International. So starting at the IF for this approach makes a lot of sense. Next month I’ll show you some new GPS approaches where you cannot start at an IAF! All the more reason to know how to start at an IF.

  • Max Trescott

    Dean, I agree, the NorCal TRACON controllers do an excellent job!

  • Bob Blum

    I have always thought that an intermediate was a fix labeled IF on an approach chart. Since there is no IF label next to DOCAL, I question weather or not DOCAL is an intermediate fix. What is the definition of an intermediate fix?

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