by Charles Gulick
Moving Right Along
Continuation to Olympia, WA
There are no parameters to set. Pick up right where you left off in the preceding chapter.
Hopefully, you're now on the 138 radial to the Olympia VOR—and because the OMNI station is right ther—to Olympia Airport. You're on top (of the clouds), straight and level at 7500 feet, and it took some adjustment of your controls to get here.
In both Cessna and Piper, as your altitude increased, you needed regular advances of power setting to hold the 500-FPM climb rate. In Piper, you had to give a notch of up elevator eventually, because even full power wouldn't hold you at 500 FPM. Cessna had a notch of power in reserve.
If you applied your best procedure to the climb and to getting straight and level, your tach in Cessna now reads 2305 RPM, and you are flying with a notch of down elevator. In Piper, your elevators are at operational neutral (you took off the notch of up after you got to altitude), and you're alternating between 2250 and 2350 RPM to average out your altitude at 7500.
By “best procedure,” I mean that you first adjusted power to maintain your climb, and then used elevator when power wouldn't do the job. Then, in straight-and-level flight, you took off the elevator and tried to get in balance using power adjustments. If that gave you an unsatisfactory result—didn't hold the altitude well—you adjusted the elevator, and then again power to find the best combination.
At the moment in my Cessna and my Piper, I am 30 nautical miles from Olympia. If you're in that general area, fine. If not, you may want to adjust the turn instructions that I develop below.
I'm going to show you a neat trick and give you a chance to try the radial change procedure described in the first leg of this flight. We're going to move from radial 138 to radial 170.
The following is a short synopsis of the technique:
- Be sure you're tuned to the right VOR frequency (Olympia).
- Find out what TO radial you're on. (If everything's as it should be, you already know you're on 138.)
- Head to center the needle on that TO radial. (Again, we'll hope it is already centered.)
- Reset the course selector to the desired radial (in this case 170).
- Turn to intercept the desired radial. (If you mentally picture yourself on spoke 138—your current heading—on what you know is a clockwise-numbered wheel, in which direction does spoke 170 lie?)
So enter a standard rate turn in the direction of spoke 170, rolling out on a heading different by about 60 degrees from your original 138 heading.
I trust you turned left and rolled out on an approximate heading of 78 degrees (138 minus 60 equals 78).
Now while you're crossing the spokes, heading to intercept radial 170, tune your auxiliary navigational radio, NAV2, to the same VOR, Olympia, and use your course selector (the OBS) to center the needle. The resultant NAV2 readout will tell you which radial you're on.
However, you're soon off it, because you're flying across rather than along the spokes. So adjust the NAV2 selector fairly regularly to keep track of your progress. You'll see that you are indeed flying in the right direction to intercept 170, because the radials you're crossing have ever higher numbers. You're crossing radials fairly smartly, too, because you took an approximate 60-degree cut. A significantly lower cut would have meant an inordinate amount of time to make the change.
Notice something else interesting: Of the four instruments on your panel capable of giving you directional information, only your heading indicator and your compass agree—at 78 degrees, which is your actual heading. Your two OBIs don't agree with either your actual heading or each other. As presently set up, NAV1 indicates where you want to be—the 170 radial—and NAV2 tells you where you are—on which radial—at any given moment.
When NAV2 shows you on or near the 160 radial, the NAV1 needle pops on scale, confirming that you're ten degrees or less from your destination. When the latter needle comes to the edge of the center circle, it is time to turn and intercept. Bank to your right and get on a heading of 170 degrees.
Now immediately reduce your power setting to slowflight—in Cessna 1505 RPM and in Piper 1200 RPM. Then reduce your power another two notches. Cessna, your tach will show 1255 RPM. Piper, your throttle-position indicator will be one notch from the bottom.
Now use elevator trim to keep your descent rate as close as possible to 500 FPM. Keep trimming, and don't let that rate get too far away.
Meanwhile correct your position as needed to keep the OBI needle centered, and continue your regular instrument scan.
Given good trim procedure, your aircraft will settle into a controlled 500-FPM descent at its slowflight speed—70 KIAS in Cessna, and oscillating between 80 and 100 KIAS in Piper. Each time the glide shallows, add a notch of down elevator to correct.
When you break out of the overcast, your destination airport will be directly ahead (hopefully). The runway for which you're almost lined up is Runway 17, but your landing will be on 26 due to the surface wind, which is 255 degrees at four knots. The reason you're not exactly lined up is that your bearing is to the VOR station rather than the runway threshold. But this little experiment shows how precise an approach you can make, even to a specific runway, using just your OMNI capability—the one on your panel and the one in your head. This wasn't an ILS approach, but it was nonetheless an instrument approach in bad weather without visual reference to the ground until the very end. If you could see the airport at all when you came out of the clouds—even behind you—congratulate yourself. You're getting somewhere.
Just add power to make the transition from your descent to straight and level when you're ready. Your usual slowflight RPMs should do fine: 1505 in Cessna; 1200 in Piper. The business end of Runway 26 is to your left. Pattern altitude is 1200 feet, pattern left-hand, field elevation 206 degrees, and your best bet is to go around the airport to the right, entering the downwind leg (80 degrees) on a 45-degree angle—given, of course, that you came out of the overcast on this side of the airport.