When I was doing my instrument and multi-engine training, we did a lot of circle to land approaches. As a student, I could never figure out why these types of approaches would ever be practical when you could an approach straight in to another runway. But, as a good student, I never asked my instructors the purpose of them, I just did them to the best of my ability.
Now, having been flying in the IFR system for almost a decade, I’m finally beginning to fully understand the practical purpose of a circle to land approach. I have actually elected to do an approach where I had to circle to land on several occasions in actual IMC conditions.
One important note to remember on circle to land approaches is that the minimum descent altitude (MDA) is always higher than on a straight in approach. The reason for this is that you are basically joining the pattern for a different runway and you have to be able to visually keep yourself clear of towers and other obstacles. So, you need a higher visibility and a higher ceiling than if you were just lining up to come straight in.
Here are a couple of practical circumstances where it would make sense to do a circle to land approach.
Airports with only 1 straight in approach
This one is easy. There are a number of airports scattered around the US that have only 1 straight in instrument approach published for it. Around my part of Texas, the first one that pops into my mind is the RNAV 31 at T85 in Yoakum, TX. Most of the year, the prevailing wind is out of the south, so 13 is the favored runway at T85. During the winter is when most of the IMC weather happens in South Texas, so that is why the approach is for 31.
Of course, especially this year during the summer, there are some IMC days where an approach to T85 would be necessary. When there is a strong wind out of the south, landing on 31 is impractical, so a pilot would fly the approach to 31, then circle to land on 13.
Approaching from the opposite direction
Take a look at the RNAV 19 at KBMQ, Burnet, TX. The two initial approach fixes (IAF) are IXANY and JIBAJ. If a flight is approaching BMQ from the west or north, this is an easy approach to join. If a flight is coming from Austin (directly the the east and a little south) or San Antonio (almost directly south), it would be a bit of extra flying to get configured properly for the approach. Especially coming from Austin, because the degree of turn to join at JIBAJ wouldn’t make the approach practical.
Well, how about vectors? Unfortunately, Houston Center doesn’t have this approach depicted so vectors aren’t a possibility. Center can give you vectors north to make the angle a little easier to join at JIBAJ, but they can’t vector you onto the approach.
Direct DLORA to join is another option, but again, if you are approaching from the southeast, the angle is wrong.
Insert the RNAV 01 approach with a circle to land. AMUSE is right on V163, so it’s really easy to join the approach there coming from the south. Coming from Austin, joining the approach at SUBIE works out great. Fly down to the MDA, join the left downwind for 19, and everyone is happy.
VOR Circle to Land Approaches
Every instrument pilot has had an instructor “force” them to do a VOR A or VOR B approach and no one enjoys them. I personally think they are good practice. With the number of RNAV systems and RNAV approaches out there, though, VOR approaches are becoming a bit archaic.
They do have a place in this discussion, though. A VOR approach is given an A or B designation when the angle of the final approach course is greater than 30 degrees to the runway (VOR A KLZZ), or the final approach course is lined up with the runway, but the MDA is too high to practically descend and land (VOR A KGRK or the VOR/DME C KASE).
So, there are practical uses for a Circle to Land approach. The next time you do some IMC work with an instructor, ask him/her if you can include one.