RFT 285: Flying A Manual ILS

In this age of flight directors, flight management computers and autopilots, it's easy to get into the mode of letting the automation do all the work. And that's good if it enhances safety.

But it's really important to keep your basic stick-and-rudder skills current, and that includes flying an ILS approach without any of the bells and whistles.

So let's discuss a hand-flown ILS flown WITHOUT a flight director or autopilot.

The key to successfully, easily flying a manual ILS is preparation. First, study the approach chart, so you have a complete understanding of all the facilities involved. Take a look at the distance from the glide slope intercept point and the outer marker (if it's part of the approach) to the runway. Examine the glide slope angle, and note if it is OTHER than the standard 3-degrees.

Now, as close to your ETE as possible, get the destination weather. Ideally, this will be right before you prepare for your approach. Now, take out your E6B computer and calculate your groundspeed and wind correction for the approach. If you can't remember how to do this, listen to episode RFT 146 and PRACTICE with your E6B until you can solve a wind problem in under 30 seconds. The only thing that makes this calculation different from what you do with the E6B for your cross-country planning planning is that you will be using only MAGNETIC winds (from ATIS), rather than winds oriented to true north.

When entering your true airspeed into your E6B, you need to know your true airspeed (TAS), based on your indicated airspeed (IAS). You can use the calculator side of your E6B to determine TAS (RFT 148), but, as a guide, TAS increases 2 percent for every 1000 feet above sea level. So, if you are flying your approach at 120 KIAS at an average elevation of 6000 feet MSL, your TAS is [120 + 120(.02X6)] = 120 + 14 = 134. THAT's the number you use for TAS in your E6B.

Once you have calculated your GS and WCA, calculate your descent rate and heading to keep yourself on the localizer and glide slope. Now that you have your groundspeed, you can calculate your 3-degree descent rate by multiplying HALF your groundspeed times 10. In the example above, our descent rate will be 670 feet per minute (FPM).

All of this, of course is simply a guide to get you into the ballpark for an easy, stabilized approach. But if you start out with these values, you will only need minimal corrections to keep your LOC and GS centered.

The only thing left to do when you get to approach minimums and visually acquire the runway is DON'T CHANGE ANYTHING. If you have a crosswind, the runway will not be DIRECTLY in front of you, it will be offset by your WCA.

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