My plans to fly to Ottawa this weekend fell through, so I thought I’d use the time productively. So I booked a plane this morning, and got one of the other club members to be my safety pilot.
My goal was to fly 6 approaches and a hold, not just to reset the clock on my currency requirements, but to have a chance to fly some approaches without an instructor making me do things the way they do it on a checkride. When I fly for real I use a handheld GPS, and so I wanted to fly my practice approaches with it just to have a chance to see the best way to use the GPS.
Aside for the non-pilots in the crowd:
The purpose of an instrument approach is to get you and your plane in the right place at the right altitude so that you’re able to get below the clouds and see the airport, but while avoiding hitting anything solid. If you get to where the approach takes you and you can’t see the airport, you have to “go missed”, and either try the approach again, try a different approach, or go to where the weather is better. There are a couple of basic types in use in modern types:
- NDBs – Non Directional Beacon. An arrow points directly to the beacon. That seems simple, but it’s actually the hardest type to fly. These are thankfully dying out, but they’re still popular in Canada.
- VORs. You tune the “radial” you want to fly, and an indicator shows you how far left or right you are of that radial. It’s hard to explain why, but that’s WAY easier to fly than an NDB. VORs also may have DME (distance measuring equipment) that tell you how far you are from the navaid.
- Localizers. Like a VOR, but there is only one “radial” you can fly, and it’s much more sensitive than a VOR.
- ILS. These are the Cadillac of approaches – the ones the airlines fly. All the previous approaches you get vertical guidance by flying the approach, and at particular points (identified by a cross radial from another VOR, or a DME distance, or by crossing the actual navaid, or by timing) you can descend to a particular altitude and then continue at that altitude – the so called “dive and drive”. The ILS is different – it has a “glideslope”. As well as a needle to tell you if you’re left or right of the course, you’ve also got a needle to tell you if you’re above or below the glideslope. Because it’s very sensitive and because you are continually descending down to the runway, you can get much lower than on the other types of approaches, which is great if the clouds are low. Because they’re the ones the airlines fly, they generally lead to nice long and wide runways. Which is good, because if you’re going to mix it up with the big boys, you’d better be prepared to fly a fast approach.
- GPS. There are a variety of different GPS approaches, but I don’t fly them because you need a built-in GPS to fly them, not just a hand-held.
It was a pretty windy day today, and the weather map was showing an occluded front right across the area. That meant gusty winds and sudden wind shifts, and bumps from mechanical turbulence down low. I briefed Paul (my safety pilot) on the plan – I’d filed IFR out to the Geneseo VOR and back, with “multiple approaches” in the remarks. I was planning to hold at the VOR, and then do one VOR-A approach to a nearby airport, then come back to Rochester and do one NDB approach just to torture myself, then do 4 ILSes. It was likely that we’d be in and out of the clouds, so I told Paul that I would keep my foggles (view limiting devices to simulate instrument conditions) on the whole time and he was to do the usual safety pilot stuff (look out for other aircraft, make sure I don’t hit the ground or anything pointy sticking up) but also to make sure I don’t pick up any ice on the wings in the clouds.
Another aside – I hate foggles. Not only are they somewhat uncomfortable, but they break the seal on my headphones, so that the automatic noise reduction turns off, hitting me with a wall of noise until I can reset it.
I can’t believe how much the GPS helps. I had the moving map as I approached the hold – I figured the hold entry wrong, and turned in the wrong direction, but it was immediately obvious on the moving map that I was going the wrong direction and so I turned back and did a parallel entry. Actually, I think that if I ever get a real hold, I’m going to do the “no shit” hold entry I read about somewhere. It’s very simple:
- Cross the fix, turn to the outbound heading.
- Go outbound for a minute.
- Turn toward the protected side, 225 degrees.
- Intercept the inbound track.
- Bob’s your uncle.
Draw it out – this works for every entry direction. It’s not pretty, but it keeps you on the proper side which is all the controllers care about.
The other great thing about GPS is that it shows the direction you’re actually travelling over the ground. The compass and direction gyro (aka “gyro compass”) show you the direction your plane is pointed, and the navigation radios show you the direction you should be travelling, but it’s usually up to you to figure out how much the wind has made the direction you’re actually travellilng differ from the direction you’re pointing. But the GPS changes all that. You put it into HSI mode, and if the navaid is 278 degrees from you, you turn until the GPS says you are tracking 278 degrees over the ground, and you’ll get there, sure as shooting. I was tracking the VOR outbound from Geneseo on the Le Roy VOR-A approach, and even though the nose of the plane hadn’t moved at all, the GPS HSI suddenly showed my ground track had changed by nearly 30 degrees. That’s what we call a sudden wind shift. So rather than waiting for the VOR to show me off course and trying to correct back, I could anticipate the correction by turning until the GPS showed that my track over the ground equalled the track I was trying to follow.
The VOR-A approach was pretty easy because of that, although my timer expired long before the GPS showed me even close to the airport (the wind shift must have buggered up the timing) and I couldn’t even see it. I put my foggles back on, and as I climbed out Paul said he could see it. I can see how people on non-precision approaches get sucked into continuing on beyond where their timer says the missed approach point is. At least in my case I had a GPS telling me that the airport was still another couple of miles ahead, but when a friend of mine’s plane partner died on an approach, he was well beyond the missed approach point, probably still looking for the airport that he knew *must* be just ahead.
The NDB approach was terrible. At first I tried to do it “clean”, without the GPS. And the controller said “it looks like you’re being blown south of the course, turn 330 to re-intercept”. So I gave up and used the GPS, which pretty much salvaged the approach, but not entirely. In real life, I’d probably use the GPS more agressively.
All four ILS approaches were great – while being vectored around the GPS showed me where I was so I could anticipate the next vector and how much time I’d have to get on track. I didn’t use the GPS at all once established on the localizer, and I was within a half a dot deflection all the way down until about 200 feet to go, when there was a nasty wind shift. The first time it took me a bit by surprise and I went nearly three dots off, but I could still see the runway and I could have made it if I was trying to land. But after that I kept it better under control. The great thing about ILS approaches is that if you have the heading and descent rate right, once you go visual at the end of the approach, you hardly have to do anything – just continue the same heading (maybe with a minor tweak) and the same descent rate and you’ll round out about 1,000 feet down a nice long runway. Fortunately the Archers don’t float too badly on a fast approach. Planes that have more of a tendency to float need to be slowed down, retrimmed and flaps adjusted in that few seconds between breaking out, which can be a busy time.
I’m feeling a bit better about my currency, and I think I have a better handle on how to use my handheld GPS for situational awareness, especially on non-precision approaches. One thing I didn’t use it for but I should have was to watch the difference between the direction I was pointing and the direction I was tracking over the ground over the ground so that I’d have a better idea of what correction I’m going to need once established on the approach.