Sunday, October 18, 2009

2nd, 3rd and 4th Instrument Lessons

To date, I've had four instrument lessons. We're generally spending about a half hour going over the material before each lesson and then spending about 1.5 hours in the plane but today we spent most of the two hours in the plane since we knew what we were going to do.

Instrument flying is necessarily more precise than VFR (Visual) flight: on an instrument flight plan, the pilot is listening to Air Traffic Control (ATC) for instructions and then following those instructions. ATC expects the plane to be at the right altitude and heading -- this is important because the primary role of ATC is to maintain separation between planes even when those planes can't see each other. So it's critical that each plane be at the right altitude and on the right course.

"Attitude Flying" is comprised of a number of instrument skills that instrument pilots need to master. Attitude flying requires flying accurate courses at specified altitudes (within 100'), making turns at specified rates and climbing and descending, on course, at particular rates and airspeeds. Since the workload in the cockpit is higher in IFR flight, the pilot can't be constantly trying to figure what settings to use for a particular course every time ATC issues a new instruction.

Fortunately, there's a good solution. When flying an airplane, the pilot "pitches" the nose of the plane up or down through the use of the yoke. He also controls the speed of the engine (and thus the power available) through the throttle. In normal conditions, a particular pitch and power setting will produce the same performance each and every time. For example, in 70L, if I use full power and pitch the nose up 10 degrees above the horizon, the plane will climb at 90 MPH and about 700 feet per minute (FPM). If I set the throttle to 2500 RPM and put the nose right on the horizon, the plane will neither climb or descend but will instead fly along at about 110 MPH. With this in mind, instrument pilots use known pitch and power settings to achieve known performance. So one of the first things that Kyle and I did was to determine the a "power sheet" for 70L, which lists the settings I'll use for climb, cruise, cruise descent, approach, approach descent and non-precision descent. Mastering these will give me almost all of the speed and performance options I'll need for normal instrument flight.

We're using Peter Dogan's Instrument Flight Training Manual as a guide and I'm liking it a lot. It's a very clear, straight-forward book. In it, he discusses a couple of different ways that instrument pilots can use the instruments to guide the flight. The difference is in what instruments you look at and in what order to determine what is going on and what you will do next. We decided to use an approach called "Control and Performance". Basically, it identifies a couple of instruments (the attitude indicator and the tachometer) as "control instruments" that are used when making changes and the rest as "performance instruments" that you check after making a change to verify that the plane is performing as expected. For example, if I pull the throttle back and don't allow the plane to descend, I should then be able to see that the airspeed is slowing down by checking the airspeed indicator.

In the first few lessons, it became clear that I'd developed bad rudder habits through a year of visual flying, so I found myself really working to clean that up since it was a necessary precondition for precise instrument flying. I've also found a few things about 70L that I want to get corrected/modified. I'm going to take the plane to a mechanic in Massachusetts and have him check the "rigging" -- how the wings and control surfaces are adjusted. I think the plane can be adjusted to fly precisely with a little less effort on the side of the pilot and I think I'll get a little more speed out of it and maybe save a little fuel, too. Also, I hadn't noticed before that the weight of my hand on the throttle would slowly cause an RPM drop, even with the friction lock set tight (which is the way I like it). I didn't notice it before because I'm often adjusting the throttle during visual flying. But the drop in power became apparent as soon as we started instrument training. I talked to my mechanic who said "I know what that is -- that's an easy fix." Cool.

After the first two lessons, I really wondered if I was making a mistake in pursuing this. I wasn't sure that I was going to be able to learn to fly as precisely as needed and I felt like I was back at the beginning of my training again. It didn't help, I guess, that each of the first three lessons were on days when it was reasonably bumpy. Yesterday was a little calmer and, for some reason, it just kind of clicked. I had more understanding of what I needed to do and was more able to do it than before. At the end of the time, Kyle said "I didn't see more than a 50' deviation in altitude for the entire 1.5 hours and you only lost your heading a couple of times." There's still a lot of room for improvement and we'll keep working on it but I think it's fair to say that I flew more precisely tonight than I've ever flown before.

I should have gotten the instrument written test out of the way before this but I didn't, so I'm working on that reading on the side. Work has been crazy busy and family commitments are taking time, too. But I feel really good about how yesterday's lesson went and, oddly, I'd been so busy during the previous two days that I had no time to study or prepare before the lesson.

6 comments:

  1. It sure sounds like things are starting to come together. Thanks for keeping us in the loop with your IR training - it's great to read about it for folks like me who aren't able to get underway on their own just yet.

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  2. Hey Brian - I don't have your email but I wanted to ask you a question about an ELT. So if you get this, shoot me a note to steve [dot] dilullo [at] gmail [dot] com please.

    Hope all's well with the bird!

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  3. Just wanted to say good luck with the latest fun with 70L - I hate to hear about all you've gone through even if it is an excellent lesson in ownership!

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  5. Instrument flying is one of the most interesting and rewarding kinds of flying there is. Once you finish, remember to stay current!

    JetAviator7

    Aviator

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