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Home > Reference > Non-precision approaches

Flying non-precision circling approaches with course reversal




Many pilots will go through their entire online flying careers utilizing only ILS approaches, or the occasional visual approach.  Visiting smaller, and considerably more interesting airports, however, can leave the pilot with no choice other than a series of non-precision approaches.  This article explains how to fly a non-precision approach, and how it differs from a more common precision approach.

We'll use the Avalon VOR/DME-B approach as an example. The chart is available below in the Required Materials section. Consider printing the chart, or opening it in another window to get the most value from this article.

This article also assumes the reader is familiar with flying full approaches, and the role of feeder routes. Check the Related Articles for more information.

VOR/DME-B? Which runway?

Approaches are often aligned with specific runways at airports, allowing for 'straight in' minimums to be published. In such cases, the descent gradient to the field will be very reasonable, and the final approach course will be aligned within 30 degrees of the runway for which the approach was designed.  If EITHER of those two conditions are not met, the approach will NOT have a specfic runway designated in the name, but will instead have a letter, such as A, B, C, etc.

In our case, the VOR/DME-B approach into Avalon is either not aligned with a specific runway, or requires too step a descent to be considered a straight in approach. For this reason, there are no straight-in minimums published for the approach, only CIRCLING minimums.  Upon reaching the missed approach point, we will either have the runway environment in sight, or we execute a missed approach. If the field is in sight, we can descend below the circlling minimums, and maneuver (circle) to land on the runway of our choice, since Avalon does not have a control tower.

About face!  Flying the procedure turn


In the related article covering full approaches, we learned about performing course reversals using a hold entry for the KSNA ILS RWY 19R approach.  The VOR/DME-B  chart doesn't depict a hold for the course reveral at the IAF (RIGLI). Instead, a procedure turn is used.

rigli.PNG

Outbound from RIGLI (heading north) the chart calls for a course reversal to the left.  It's actually legal for the pilot to make the course reversal in any manner he chooses, so long as it is done within 10nm of RIGLI.  The amount of space guaranteed to provide terrain separation is slightly higher if the course reversal is performed on the side depicted by the chart, however, so it's always good practice to fly it as shown.

So, how to fly the procedure turn?  Any time after RIGLI, make a left 45 degree turn and proceed outbound for 60 seconds.  Make a right 180 degree turn and join the final approach course inbound.  That's it!

With that in mind, let's fly the approach.

Flying the approach from SXC

Note: The procedure has since been updated to use 3400ft, rather than 3200ft for the Feeder and Initial segments, and 2300 instead of 2100 for the Final segment, but is otherwise identical.

SXC is a feeder for this approach. Let's assume we're arriving from the west and told the following, "Cross SXC at or above 4000, cleared approach. Report RIGLI inbound"

Depart SXC hdg 352 and join the SXC R-352 outbound, descending to 3200.  Passing SXC 5 DME (RIGLI), we excecute our procedure turn, turning left to heading 307 for 60 seconds. During that outbound leg, set the NAV OBS to the inbound course of 172.  After 60 seconds on the 307 hdg, turn right to heading 127 and join the final approach course as the CDI (the needle) on the NAV radio begins to center. Make a right turn to join the final approach course. Once established on the radial inbound, start the descent to 2100ft.

Reaching RIGLI, report the position to ATC as instructed.  ATC will likely release you to the advisory frequency, so you can announce your position on unicom to sequence yourself with VFR traffic that may be at the field.  Remain at 2100ft until reaching the missed approach point (SXC 2.8 DME), or until the field is in sight, whichever happens first.

Unlike a precision approach, which provides vertical guidance and an altitude at which a missed approach must be declared (the decision height), non-precision approaches have a minimum descent altitude. This is an altitude whch is maintained until reaching the missed approach point, which is either identified using DME, GPS, or by flying for a precise amount of time from the final approach fix. Most ILS (precision) approaches, can also be flown as a non-precision, localizer approach, using different minimums and with a published minimum descent altitude rather than a decision height.  In fact, while flying a precision approach, if the glideslope is not received, or fails during the approach, it is legal to fallback to a non-precision approach, unless specifically prohibited by the notes in the approach.

Back to our approach, assuming we do have the field in sight, we circle to land on the runway of our choice. If the weather is VFR, then we would make an effort to enter the pattern in a fashion that is compatible with other VFR traffic in the area. Options include entering on a right base for runway 22, or maneuvering west of the field to enter a downwind for runway 22. If the wind conditions are not known, it is possible to cross overhead the field above pattern altitude and then maneuver for the appropriate pattern entry. If the weather is below VFR minimums, then by definition, there shouldn't be any traffic in the pattern and you can maneuver as needed to become aligned with the runway of your choice

Canceling IFR

Once you've landed safely on the ground, don't forget to contact ATC to cancel IFR. That way, they can allow other IFR traffic in or out of the field.  Until you cancel, ATC will not allow any other IFR traffic in or out of that non-towered airport.  If the weather is good, it's considered to be courteous to cancel IFR prior to being changed to the advisory frequency by ATC, that way he won't have to 'shut down' the airspace while awaiting your cancellation.  When landing at a towered field, ATC manages your IFR cancellation automatically. So, if you hear "cleared to land", you don't need to cancel IFR after you're on the ground.


Required Materials
KAVX VOR/DME-B approach

Related Materials
Flying full approaches: The John Wayne ILS RWY 19R
Provides an overview how to fly full approaches, using the KSNA ILS RWY19R as an example. Covers the procedure from the SLI and POM feeder routes.
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