Non-precision with Precision

Today was my first flight learning how to fly approaches- in the sim of course. I focused on non-precision approaches. A non-precision approach is an approach that does not provide vertical guidance, only lateral guidance.

Today I flew three different approaches. I flew the VOR-A approach to Buckhannon, the GPS/RNAV approach to Buckhannon, and the Localizer-Only approach to Clarksburg. I am going to attempt to explain how these are flown, but keep in mind that this is the most complicated part of instrument flying.

Buckhannon/Upshur County Regional VOR-A Approach



This chart can be split into 3 parts: The heading, the plan view, and the profile view.

Heading



The heading consists of all the basic information and frequencies needed to shoot the approach. It shows the name of the approach, the name of the airport, the VOR frequency used to fly the approach, the approach course, the airport elevation, all the various frequencies for the airport, and other information that may be necessary.

Plan View



The plan view provides you with all the necessary information used for lateral guidance in order to get established on the approach course. When joining the approach course, you first need to fly to an initial approach fix, or IAF. In this case, the Elkins VOR is the IAF (as you can see in the small box describing the VOR). Then, depending on the direction you are coming from, you would execute a certain procedure turn. A procedure turn is exactly the same as a holding pattern entry, except you don't actually hold. The procedure turn area is depicted by the oval shape of the course.

After the course passes past the VOR, you can follow it all the way down to the runway (which is that tiny black line). Then, the course becomes a dotted line. The dotted line is the missed approach course. If you get close to the airport and still cannot see the runway, you must then go missed and follow that course.

Profile View and Airport Diagram



Once you have executed your procedure turn and have joined the final approach course (in this case, its 309 degrees), then you switch your focus down to the profile view. Notice the number 5400 underlined. When a number like this is underlined on the profile view, it is your minimum altitude. In this case, you cannot descend below 5400 feet until you cross the VOR.

Upon crossing the Elkins VOR, you can then start descending, down to 2820. Once you reach 2820 feet, you cannot go lower until you reach HEGAT. HEGAT is a DME fix (Distance Measuring Equipment). If your plane has DME, you can identify HEGAT as exactly 7.7 miles from the Elkins VOR (Which is indicated by the 7.7 inside the letter D).

Once you pass over HEGAT, you must then determine your final MDA (Minimum Descent Altitude). First, you must determine which category your aircraft lies in. If your aircrafts approach speed is 90 knots or less, it is category A. If the speed is 90-120 knots, it is category B, and so on. Cessna 172s are category A. So looking at the minimums (beneath the profile view) beneath the category "A" section, you can find the MDA. In this case, the minimums depend on whether or not you have DME (and can find HEGAT). Assuming you have DME, you can use the HEGAT fix minimum altitude, which is 2260.

Once you descend to 2260, you must maintain that altitude until you can see the airport. If upon reaching the missed approach point, or MAP, you still don't see the airport, you must execute the missed approach procedure, which is found in the heading of the chart. According to the profile view, the missed approach point can be identified by the 9.4 DME from the Elkins VOR. If you don't have DME, then you have to time the approach using the times in the bottom left corner based on your aircraft's speed.

The airport diagram is fairly self explanatory.

The GPS/ RNAV approach is very similar to the VOR-A, except instead of using the VOR, it uses waypoints defined by GPS coordinates. It is also a non-precision approach, so you have to descend to minimum altitudes after crossing certain fixes, just like the above approach.

The localizer approach is the same thing as an ILS approach, which I explained how to fly in an earlier blog, except that it implies that the glide slope is inoperative. Instead of being able to track a glide slope all the way down to 200 feet above the runway, you have to descend in increments and your minimum altitude is increased by about 500 feet.

All three approaches that I flew today I flew perfectly. Hopefully with my next flight I will be able to fly non-precision approaches in an actual airplane.