Procedure turns (PTs) are maneuvers that allow a pilot flying in instrument conditions to reverse direction and, if necessary, loose altitude. There are mainly two flavors of PTs depicted on Instrument Approach Procedures (IAPs) - the barb and the holding pattern (sometimes called Hold In Lieu Of a procedure turn or HILO). While conceptually simple, procedure turns can cause misunderstandings with air traffic control if the pilot is not up to speed on the regulations.
As always, don't use any of the following illustrations for actual navigation.
When flying the NDB version of the MOG NDB or GPS A approach, the procedure turn is required because the pilot must fly over the NDB station to establish his/her location prior to beginning the approach and descending. Knowing where you at the start of this approach procedure is important because there's plenty of terrain around to run into. You'd be cleared to MOG at a certain altitude, cross the station, turn outbound and track the 157˚ bearing from MOG for a minute or two, then turn to a heading of 112˚ for a minute (procedure turn outbound), then turn to 292˚, intercept the 337˚ bearing to MOG, and begin descending.
It's important to note that without GPS, RNAV, or other specialized equipment, you really don't know exactly where you are while flying the procedure turn. You only have positive course guidance when you are flying inbound or outbound from the NDB and you only know exactly where you are when you cross over the NDB or when you descend out of the clouds and obtain sufficient visual references.
The most common procedure turn is the 45˚shown below. Cross the Final Approach Fix and fly outbound for a minute or two (depending on the wind and your aircraft's performance), then turn 45˚ in the direction of the barb and fly for a minute, the do a standard rate 180˚ turn and intercept the inbound course.
Another accepted procedure turn is the 80/260. Once outbound on the approach course, turn 80˚ in the direction of the barb, then immediately turn 260˚ in the opposite direction to intercept the inbound course.
You can also fly a teardrop procedure turn, but it's a little more complicated. Cross the final approach fix and proceed outbound for 1 or 2 minutes (depending on the wind and your aircraft's performance). Then you turn either 30˚, 20˚, or 10˚. How long you fly outbound depends on the offset chosen; 30˚ for 1 minute, 20˚ for 2 minutes, or 10˚ for 3 minutes. When the alloted time is up, make a standard rate turn back to the inbound course, depending on the offset you chose: For 30° turn 210˚, for 20˚ turn 200˚, and for 10˚ turn 180˚. That's a lot to remember, but it gives you added flexibility in how long you want to make the procedure turn last.
On many (most?) procedures where the barb is depicted, the PT is neither required nor expected (more on this later) when you are being vectored by ATC. But if you need to fly the PT, you can maneuver however you want as long as you stay on the same side of the approach course where the barb is depicted. You also must stay within the distance depicted, usually 10 nautical miles from the final approach fix.
Some IAPs depict a holding pattern that can be used for course reversal and I'll refer to these as HILO (Hold In Lieu Of a procedure turn). In these cases, you have to enter and fly the hold as depicted. As you turn inbound in the holding pattern, you'll be established on the approach course. The holding pattern at WINCH (shown below) may or may not be required, depending on how you approach the fix. For RNAV approaches, the Garmin units will ask you if you want to fly the hold when you load the approach, but they don't ask for other types of approaches like VOR, ILS, or LDA approaches.
Often ATC will ask you to "report procedure turn inbound" and many pilots do not understand what this means. "Procedure turn inbound" does not just mean that you've begun your turn to intercept the approach course. It means you have completed your course reversal and you are established on the inbound approach course. Seasoned controllers will often avoid the potential confusion by just asking you to "report established inbound."
When I did my first 135 indoc training several years ago, I was impressed by how Director of Ops cut the Gordian knot when he described whether or not to execute a procedure turn or a HILO on a vectored approach:
"Don't" was the simple answer.
I later expanded that simple answer a bit:
"Don't fly a procedure turn or HILO on a vectored approach without first asking ATC."
When in doubt, ask. That's the most foolproof, all inclusive answer I can offer to the often asked question "When can I or should I do the procedure turn on an approach?" That's the gist of it and if you want to stop reading now, you can.
Still reading? Well for the long answer, let's all turn in our hymnals to 14 CFR 91.175. Buried in this section of the regulations entitled "Takeoff and Landing Under IFR" is a little kernel of wisdom on holding patterns and procedure turns, stuffed in here as if there wasn't any better place. Or were the authors of the regulations just trying to create their own sort of Easter Egg hunt? We may never know, but let's press on.
(j) Limitation on procedure turns. In the case of a radar vector to a final approach course or fix, a timed approach from a holding fix, or an approach for which the procedure specifies “No PT,” no pilot may make a procedure turn unless cleared to do so by ATC.When using a Garmin GPS unit like the 430, 530, or G1000 to load an approach, especially a non-GPS or non-RNAV approach, it's easy to have a moment of confusion. Let's consider this clearance:
Barnburner 123 is cleared to the Santa Rosa airport, fly heading 310, radar vectors Sausalito, Sausalito 330 radial, BURDE, Santa Rosa 141 radial, COATI, direct. Climb and maintain ...30 miles out from STS, you tell Oakland Center that you have the latest surface weather observation (ATIS) and you request the STS ILS RWY 32 approach. Center tells you to proceed direct to COATI and to expect the ILS and so you begin briefing the approach.
You load the approach, selecting COATI as the initial approach fix since that was what your clearance contained. When you're done, you see something odd on the flight plan page: Why in the hell is the procedure turn in there?
The high workload of single-pilot flying may cause you to miss the fact that procedure turn is in the flight plan, but looking at the moving map should give you pause.
14 CFR 91.175 is pretty clear that you shouldn't fly the procedure turn in this scenario since you're going to be pretty much aligned with the straight-in approach course. Approaching from the northwest, well that would be different story. So why doesn't the 530W see that you're approaching from the south and figure out that you don't need the procedure turn? Good question ...
Now you could just fly the localizer and ignore the fact that the 530W wants you to turn around after you reach COATI, but then you'll lose the distance and time to each waypoint on the approach. To delete the procedure turn, you'll need to press the FPL (flight plan) button, press the small knob to enter cursor mode, scroll with the large knob to highlight the procedure turn, press CLR, and press ENT twice. A faster and safer solution is to cursor past the procedure turn (or HILO) and press the Direct key, then ENT twice.
In the next installment, I'll discuss vectored approaches with HILO.