Procedure turn, or not? With vectors to final the norm these days and not the exception, it's rare to perform the procedure turn. Yet, ATC may still expect it. When in doubt, ask.
These days, it's rare to do the full procedure, i.e., execute the procedure turn. Instead, ATC usually vectors a flight to join the final approach course somewhere between the initial approach fix (IAF) and the final approach fix (FAF), or we join an approach segment accompanied by the notation "NoPT." Yet, a recent issue of the NASA Aviation Safety Reporting System publication Callback highlighted how confusing the procedure turn/no procedure turn decision can be. Just exactly what are the applicable rules, anyway?
WHAT'S A PROCEDURE TURN, ANYWAY?
According to the Aeronautical Information Manual (AIM), "a procedure turn is the maneuver prescribed when it is necessary to reverse direction to establish the aircraft inbound on an intermediate or final approach course." In essence, it's a specific maneuver designed to allow operators both to reverse course in a defined way and to align with the the runway when approaching from an "awkward" direction. A variation is the "hold-in-lieu-of" procedure turn, which we'll get to in a moment. When depicted on a chart, the procedure turn is mandatory. Except when it isn't.
For example, it's never executed when the notation "NoPT" is associated with a an initial approach route segment. Likewise, it isn't executed when ATC provides a radar vector to the final approach course (more on this in a moment). It's also never used when conducting a "timed approach from a holding fix" (when was the last time anyone did that in U.S. airspace?). But if you really, really want to execute a procedure turn where one isn't necessary, or mandatory, you can. Just ask ATC and receive an appropriate clearance. You might have to wait a bit for it, though.
With respect to altitude and speed, both are handled in a fairly simple fashion. The altitude at which you enter the procedure turn is mandatory and easily found in the procedure's profile view. For the procedure reproduced below, that's 2100 feet. Once established on the inbound course, you may descend to the next minimum altitude. On the approach below, that's 1700 feet.
The AIM tells us "a maximum speed of not greater than 200 knots (IAS) should be observed from first overheading the course reversal IAF through the procedure turn maneuver." This helps ensure the turn is completed within the prescribed airspace. Rather than speed, though, think about time/distance from the fix at which the procedure turn is performed. Depending on what's published for the procedure, you'll need to complete it within 10 nm, or perhaps within a specific time. A one-minute hold is depicted on some procedures; the one below uses five minutes.
Generally, a procedure turn consists of a 45-deg. turn in the direction indicated on the procedure, followed by a 180 in the opposite direction, then a final 45-deg. turn to join the final approach course. Other types of turns can include the racetrack pattern, the teardrop procedure turn, or the 80/260-de-gree course reversal. In all cases, the direction to turn is either indicated by the barbed arrow or to the side of the final approach course where the holding pattern is depicted. Both are protected airspace, set aside just for your course reversal.
HOLD OR TURN?
A final characteristic of procedure turns: When a teardrop procedure turn is depicted and a course reversal is required, this type of turn must be executed.
But what about when a hold, or racetrack pattern, is depicted? This is the aforementioned hold-in-lieu-of procedure turn, which may be specified for course reversal in some procedures. Just as with a "normal" procedure turn, it's established at an intermediate or final approach fix. Also as with a procedure turn, the confines of the protected area must be observed. This is determined by the distance or time specified in the procedure's profile view.
For a hold-in-lieu-of procedure turn, fly the holding pattern as depicted. One twist from a "straight" procedure turn is you should fly the pattern at or below the maximum holding airspeed applying to all holding patterns. The holding pattern maneuver is completed when the aircraft is established on the inbound course after executing the appropriate entry.
In other words, one doesn't enter the hold unless specifically cleared for it. If you're cleared for the approach after leaving the holding fix outbound on the entry but prior to returning to the holding fix, and the aircraft is at the prescribed altitude, you may proceed inbound to the final approach fix--additional laps around the holding pattern aren't expected by ATC and could get you into hot water unless you've requested and are cleared for them. Reasons for additional turns in the hold vary, but could include a need to descend or to better align with the final approach course.
NOPT AND OTHER NOTES
Those are the high points of procedure turns. The sidebar at right depicts various aspects of how the procedure turn is charted, along with how it's designed to ensure obstacle clearance.
One of the important things to remember about procedure turns is when not to execute them. According to the FAA's Instrument Procedures Handbook, FAA-H-8261-1A, and as discussed above, "When ATC is radar vectoring to the final approach course, or to the intermediate fix as may occur with RNAV standard instrument approach procedures, ATC may specify in the approach clearance "cleared straight-in (type) approach" to ensure that the pilot understands that the procedure turn or hold-in-lieu-of-PT is not to be flown."
With the proliferation of approach types these days, plus the increased automation available, it's not always crystal clear to pilots when they should or shouldn't be executing the procedure turn. Both the AIM and the FARs (FAR 91.123) agree: Immediately ask ATC to clarify its expectations. Meanwhile, we wouldn't discount the theory ATC isn't always clear on when a procedure turn is necessary, either.
RELATED ARTICLE: CALLBACK
From NASA's Aviation Safety Reporting System
The Aviation Safety Reporting System (ASRS) run by NASA is always a good resource for highlighting problems other operators are having. There's no difference when it comes to procedure turns.
SANTA BARBARA, CALIF, VOR/GPS RUNWAY 25
Received radar vectors for sequencing prior to KWANG, then proceed direct ZACKS (the FAF and also an IAF), maintain 2100 until established, cleared GPS 25 approach. Shortly thereafter, I was instructed to contact the tower.
Per AIM 5-4-9, a procedure turn is required with this clearance. ATC provided no radar vector to intercept the final approach course, nor did ATC assign a straight-in approach. Considered as an IAF, ZACKS does not have a NoPT indication, vs. KWANG, which does. The fact that the assigned altitude (2100 feet) was below the 3000 foot floor of the outbound procedure turn segment aroused my suspicion. I queried the tower controller, who informed me not to perform the course reversal and proceed straight in. I was able to do so safely and landed without incident.
WESTMINISTER, MD., VOR RUNWAY 34
After receiving several vectors for traffic flow, I was cleared direct to EN, the IAF for the approach, when I was about 10 nm away from the VOR. The controller subsequently cleared me for the VOR Runway 34 approach at DMW, and I proceeded to execute the hold-in-lieu-of-a-procedure-turn per the published procedure. While I was on the outbound leg of the hold, the controller told me that he did not clear me for the procedure turn, and told me that he needed me to turn inbound right away. I immediately complied and completed the approach.
According to the ASRS, "The words straight in were not part of the approach clearance."
BURLINGTON, WASH., RNAV (GPS) RUNWAY 10
ATC cleared us direct to SOCLO intersection, the IAF. We were on a north heading. A clearance was later given to cross SOCLO intersection at 4000 feet and cleared for the RNAV 10 approach. Since we were at 4000 feet and the initial altitude for the approach was 3900 feet and we were not on a transition, we assumed to be cleared for straight-in. At SOCLO we turned inbound and resumed the approach without entering the procedure turn. Whidby Approach informed us that we were not cleared for a straight-in and that we should have conducted the full approach.
RELATED ARTICLE: Charting the PT
The procedure turn is charted in various ways. As depicted at right in Figure 1, a racetrack, or hold-in-lieu-of procedure turn, is present on the T-configuration RNAV/GPS approach planview. As this article's main text discusses, when such a course reversal is depicted, flying enough of the hold to return to the holding fix aligned with the final approach course and heading inbound is all that's necessary.
[FIGURE 1 OMITTED]
When not flying the hold-in-lieu-of procedure turn, one of the three other course reversals depicted in Figure 2 is expected, with one exception. That exception involves the teardrop course reversal/procedure turn. When depicted, it must be flown. Otherwise, you're free to use either the standard 45/180/45 procedure or the 80/260.
[FIGURE 2 OMITTED]
Figure 3, at bottom, depicts both a plan and profile view of a typical course reversal with controlling obstructions both inside and out-side the primary area's protection. The red line and arrow show the direction of flight to properly enter the protected area and execute the turn. This graphic demonstrates why staying within the procedure turn's protected airspace whether defined in miles or minutes--is a good idea.
[FIGURE 3 OMITTED]
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||INSTRUMENT FLIGHT; air traffic control|
|Author:||Burnside, Joseph E. "Jeb"|
|Date:||Jul 1, 2012|
|Previous Article:||Automation--friend or foe? The real answer requires us to look beyond the past century and recognize that we live in a new world.|
|Next Article:||Living with ADS-B: it's here and available, especially if portable equipment is appropriate for your operation or you fly an experimental. Should you...|