ILS, the Instrument Landing System, is a pretty nifty set of radio antennas installed in some airports to assist with, as the name suggests, landing. I could spend pages describing in HAM geek-speak how fascinating the radio science is behind the various sections of ILS are. But I’ll spare you the technical details, which you can find here, here, and here.
In essence, the ILS signals that are radiated from a runway spread out in a 3D pattern. There are the localizer signals, which give you left and right guidance, the glideslope signals, which essentially tell you up and down, and various marker beacons that notify you how far you are from the start of the runway, often known as the outer marker (OM), the middle marker (MM), the inner marker (IM), and sometimes the back course marker (BCM). With all these radios shouting various things at your airplane, if you tell it to listen to them (i.e. tune NAV1 to the ILS frequency), you almost can’t help but make a good landing.
I, on the other hand, suck at landings. Thankfully I only suck at them in X-Plane so far. Watching the VASI, the row of lights that helps give you the visual on your glideslope, is obviously useful. But without having actually flown anything in real life, I wasn’t sure what a good landing was like in the sim. I found myself cutting the power, lowering the flaps in sections on the approach, and praying as I lined myself up properly.
Prayer may be the friend of a pilot, but the hand of God alone hasn’t landed any planes that I know of.
Then it hit me. Why couldn’t X-Plane teach me? I started sifting through the X-Plane documentation and forums to find out how to use the Autopilot and ILS. And wouldn’t you know it, the first time I tried it, after setting myself up in a 747 at 10nm from San Fran’s KSFO airport landing ILS on runway 28L (the approach over the bay is rather beautiful), it worked like a charm.
Reality check time. I certainly don’t think I’ll be flying 747’s. Nor do I think I’ll be landing on 28L at KSFO any time. So why go through this? Well, by using the Autopilot with the ILS, X-Plane taught me what the ‘right’ way to land ‘felt’ like. By ‘right’ way, I mean riding the ideal glideslope, perfectly centered on the runway. Given the lack of physical sensations in the sim, I wasn’t exactly sure what a smooth landing should be like.
After doing it a couple times with the 747 in various weather conditions, setting the glass cockpit display to show me the control surface deflections (the little meters that show you the elevator, aileron and rudder statuses) and watching how the Autopilot used the controls to counteract the various winds, I felt like I spent an hour learning more than I’ve learned thus far about landings.
I then set the weather to clear and loaded the Cessna 172. NAV1 was set for the ILS (I think it’s 109.55 on KSFO’s 28L), and I watched my VOR head like a hawk, kept my eyes on the VASI, corrected my glideslope according to the VOR/VASI information, eased back the throttle, and let the flaps down bit by bit on the approach. As the back wheels kissed the runway (without bouncing) I eased forward on the stick. The front wheel landed, and I braked.
My first real landing. In a simulator. Far from picture perfect, and I’m certain there are a million more things I need to do during a landing. But as I shut down the computer that evening I realized how much I learned in those few hours. Even if only a little bit of it will spill over into the real world, it’s a little bit more than I knew before.
For the next few nights, it’s landings, landings, and more landings, with and without ILS. I hope my neighbors aren’t disturbed by the late-night airplane sounds…
