- "Pattern selection should be based upon an individual assessment of the procedure turn requirements to include wind, complexity, the individual preparedness, etc." (p. 7-32).
So how does an instrument pilot properly assess wind, complexity, individual preparedness, and so forth in determining which pattern to use? The simplest way to figure it out, like most things in aviation, is to go try it. And that's what a student and I did this morning. He happened to capture our track on Foreflight, and I figured I'd share it with this audience since many will find it to be useful in their real world flying and simulated flights here on Pilotedge.
We used the Cedar Creek VORTAC (CQY) just southeast of Dallas, TX as the basis for these procedures. To practice these patterns, we first simulated flying outbound on the Cedar Creek 180° radial, imagining it to be our final approach course. After we executed a procedure turn and proceeded northbound along the 180° radial, we continued over CQY and did the same thing along its 360° radial. We alternated back and forth until we had completed all of the procedure turn patterns twice, except for a second round of the "Teardrop" pattern, which we completed during a practice instrument approach later in the flight.
The wind aloft, as noted in the diagram, was from 090° at 15 knots. Consequently, we had better success with the patterns known as the "Standard 45°" and the "80°/260°" than we did with the "Teardrop" pattern, which we only did one time.
In this case, we performed a teardrop with a 30° divergence for 1 minute; however, the Instrument Flying Handbook describes this same technique using a 20° divergence for 2 minutes or 10° divergence for 3 minutes, either of which are suitable alternatives, and both of which would likely have worked much better. The 30° divergence gave us a hefty tailwind that blew us quite a bit away from the final approach course, hence the lack of any course intercept on the inbound leg. This probably would not have worked on a real approach.
All in all, it was a great little experiment that gave my student a good look at the different procedure turn patterns.
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