Tuesday, August 22, 2006

Feeling the controls, finding reference points

On Sunday morning, Husband and I went up in 388 for about an hour-long flight. The main purpose was for him to check the glideslope because he didn't think it was working. We elected to go up to KFCI (Chesterfield) to test it.

We were maybe halfway there, on the south side of the James, when he suggested I take the controls. It wasn't the first time I'd "flown," but it was definitely the first time I was "trying to fly" -- that is, in the past it was kind of leisurely and sticking to an altitude or heading was not part of the experience, but this time I wanted to do things deliberately and learn something.

It was a little breezy, so keeping the heading wasn't a gimme. Minor corrections were required fairly frequently, and since the path to our destination had us just skirting the RIC airspace, I had to keep on top of it. Husband has explained about finding a reference point in the distance and making a "sight picture" (I think that's what he calls it), then using those two pieces to maintain heading and altitude. Unfortunately, it was very hazy and so the horizon wasn't visible, thus I had to repeatedly check the altimeter to be confident that I was maintaining altitude.

I did learn that my choice of reference points needs some refinement. My process was to check the GPS to see that my heading was correct (I couldn't see the heading indicator from the right seat so well) and then look straight out and select something in our path. I would then fly toward it for a few minutes, then glance down at the GPS to check the heading again; invariably, I had drifted one way or the other. So I'd repeat the process, and after a few minutes would still have drifted. I expressed this deficiency to Husband and he said something about picking something off the nose (and that was bad) but it didn't quite synch with what I was feeling at the time. I did find that if I selected *two* reference points, one nearby and one more distant, and tried to keep them in the same alignment that it worked out better. Perhaps with practice... [edit: Husband says what he asked was whether I was pointing the nose at the reference point; since there were winds from the left, I'd need to point to the left of my ref point to compensate if I wanted to keep tracking directly to it. I'm not sure in retrospect what I was doing, exactly, but will keep that in mind next time.]

When we were certain of clearing the RIC airspace, it was time to turn our heading from ~270 to ~331 to try to pick up the ILS and check the glideslope. I turned us and kept checking the altimeter to make sure that the plane stayed where we thought it should be. I know there's something about planes wanting to climb or descend when turning, but I don't know the details yet and it wasn't obvious to me in that turn. If I had to guess, I'd say they probably want to descend during turns.

Once we were heading toward the airport, thanks to the winds, I found I had to point the nose to the left of the runway to maintain our path straight in. This is called "crabbing." Husband verified that the glideslope was not being triggered (but the localizer was just fine) and called off the approach. He had me tip the left wing up so we could check for traffic and then do a hard turn to the left. He had me use some rudder (right, I think [edit: Husband says it was left. See below.]) but I was so focused on keeping altitude and the feeling of the turn that it didn't sink in -- this was by far the hardest turn I had executed. The rudder changes where the nose points; right rudder means turn the nose to the right. If we were banking hard to the left while using right-rudder, it seems that would be to maintain altitude. This is called "cross-controls" -- banking one direction while applying opposite rudder. Perhaps left rudder could have been used on our FCI approach to execute the crab. [edit: Husband says you wouldn't use rudder to steer. "Coordinated flight" is when you use rudder and bank inputs in the same direction, and the aforementioned left turn would have been "bank left with left rudder." He started to explain the turn coordinator and how you "step on the ball" to correct, but the forces just don't make sense in my head yet -- we're going to look at his training book tonight. Aside from that, power above cruise makes the plane want to veer left (factory tunes the rudder to be neutral at cruise) so in that case you use right rudder to compensate; the opposite is true for power below cruise; take offs, with lots of power, require right rudder to stay straight on the runway.]

Leaving FCI we wanted to climb back to 3000'. Husband said we'd increase the throttle to accomplish this. I'm not sure I understand yet why; the best reasoning I can give now is that increased thrust would increase lift. Later in the flight we also decreased power to descend. In any case, while powering up, Husband instructed me to apply some rudder again. The engine torque, he explained, tries to pull the aircraft one direction so we compensate by applying controls in the opposite direction. Which direction? I don't know. I was feeling a little frantic at the moment because I was fighting the airplane over altitude; it had climbed quickly (or so it seemed to me) and we were nearing our target altitude so I was trying to level off and felt I had to wrestle it, all while trying to maintain heading to avoid RIC and simultaneously try to process what Husband was saying about power and torque. The power and torque explanation came in last for getting my limited attention and unfortunately didn't get absorbed.

But from that wrestling came another practical lesson: trim tabs. Once I told him what was going on, Husband reminded me that we were still trimmed from the first portion of the flight, so I adjusted the trim wheel and 388 became much more cooperative at that point. He said that as we throttled back in a moment that I'd need to re-assess where the trim was set because I might find that I was fighting it again. This was also when we talked about not using the trim to fly, but only as an assistant -- the trim is not an auto-pilot for that axis :)

Part way back, I decided to start some safety training as well. The south side of the James is mostly farmland and forest, so we talked about what would happen in an emergency landing situation. I was asking about the glide capabilities of our plane and what that translated to as far as fields we could see and where we would want to land if some unfortunate situation arose. I already knew some criteria: open and flat; avoid trees and cows and power lines; parking lots are bad (think of concrete parking blocks that you probably can't see until the last minute). With farmland there may be barbed-wire fences lining some fields, so be careful of that. Husband indicated that he tries to find two adjacent fields, one behind the other, if possible in case the extra room is needed. He pulled back to idle so we'd more closely simulate the situation (occasionally he'd throttle back up to "clean" the engine, noting that it doesn't like to idle for too long) and we picked a nice big field slightly ahead and on his side of the plane. The tact here was to pick something close that we knew we could make and then to plan to circle around and dump altitude on approach. With that part of the plan in place, we talked about other emergency procedures such as radio'ing to give info about the plane, the passengers and our location; advising passengers; killing the fuel and electronics at the last second to avoid sparks and minimize factors we'd have to worry about if things went badly; cracking the doors; etc.

What did I learn from all of this?
  • I need to work on my reference point selection.

  • Visually maintaining altitude is difficult when the horizon is obscured by haze.

  • Cross-controls will be useful when I have a better feel for them and the use of the rudder is instinctive.

  • Changes in power require adjustments in flight controls.

  • Trim tabs can be your friend or your nemesis! :) (Just gotta remember to use them properly.)

  • An emergency landing is a scary possibility but just like with learning to drive, focusing on safety and the process of assessing options up front so that it becomes second nature is a must.

  • I'm going to like flying!

  • Husband is planning to use me as a chauffeur when we start taking trips.

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