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4 Answers

IF and FAP…

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FAA Regulations, Instrument Rating

Simple question from student... Def. of IF: the point when you fly from IAF, fly inbound and intercept the final approach course. Not every IAP have IF. Def. of FAF: the point when you do PT, fly inbound and intercept the final approach course. Only happen in NPA...usually on on site VOR app. So...basically, they have the same def., right? If the IAF is on site VOR?

4 Answers



  1. John D Collins on Apr 30, 2015

    Sih-Cheng, instrument approaches are normally broken into four segments, the initial segment which begins the approach usually at an IAF, the intermediate segment which usually begins at the IF (intermediate fix). The intermediate segment is used to allow the aircraft time and space to slow to approach speed and make any configuration changes needed for the final approach segment. The final approach segment is used to descend to the MDA/DA and ends at the MAP. The missed approach segment provides a path to the missed approach hold.

    As far as I know, all approaches have an intermediate segment, although not all will have an intermediate fix. For example, an approach with a PT and a common FAF, IAF located at a VOR or NDB. The VOR or NDB is both the IAF and the FAF. The outbound leg from the IAF is the initial segment and once you reverse course, the inbound to the same fix, now the FAF is the intermediate leg.

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  2. Shih-Cheng Chang on May 01, 2015

    Hi John, Thanks for your reply. Here is what I feel confuse.

    Here is what Jeppesen said….

    “In some cases, an intermediate fix is not shown on an approach chart. In this situation, the intermediate segment begins at a point wehre you are proceeding inbound to the final approach fix, are properly aligned with the final approach course….”

    In AIM, FAA said:”FAP, where the aircraft is established inbound on the final approach course from the procedure turn and where the final approach descent may be commenced. The FAP serves as the FAF and indentifies the beginning of the final approach segment”

    So….for ex. on site VOR app….after IAF(say VOR), outbound PT…then inbound PT….then intercept the final approach course. Is this point FAP or IF(the begin of Intermediate)? Or both?

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  3. John D Collins on May 01, 2015

    Shih-Cheng,

    Assuming the VOR is both the IAF and the FAF, you first fly to the VOR, usually along an airway to it. At the VOR, you treat the VOR as as the IAF where the approach commences and turn outbound on the charted course. The flight outbound is considered the initial segment, You then perform the course reversal using the PT and intercept the charted course back to the VOR. This leg is treated as the intermediate segment and the VOR is now the FAF. After passing the VOR inbound to the runway, you are on the final approach segment. Most of the time, the intermediate segment is aligned with the same course as the final approach segment. When the controller uses the terminology of vectors to final, they are really vectoring you to the intermediate segment, even though the intermediate course is on the same extended course centerline from the runway. So often, the intermediate segment is called the final approach course. When the course changes at the VOR (it is permitted to be up to 30 degrees different), then the extended runway center line is different than the intermediate course and it would be improper to call the intermediate leg as the final approach course.

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  4. Kris Kortokrax on May 01, 2015

    I think that the situation described in the original post would be one depicted in the following VOR approach to runway 4 at IKK:

    http://aeronav.faa.gov/d-tpp/1505/05278v4.pdf

    The VOR is on the airport and is the IAF. One flies outbound a suitable distance, performs the procedure turn and flies inbound toward the airport. There is no FAF. The VOR is the MAP.

    The initial segment would proceed from the IAF to the procedure turn. Once the procedure turn is completed, one would be on the final segment. There does not appear to be an intermediate segment in this case.

    97.3 defines the initial segment as follows:

    Initial approach is the segment between the initial approach fix and the intermediate fix or the point where the aircraft is established on the intermediate course or final approach course.”

    This would seem to indicate that the initial segment could be followed by the final segment with no intermediate segment.

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