Sunday, March 27, 2005

 

Flying Lesson #11: Actual IMC

I didn't have a lesson scheduled for today, but I did check the airport weather like I do every morning, just for practice. The current conditions were 400-foot ceilings, and the forecast called for afternoon thunderstorms. "I guess nobody's going to be flying today," I thought. Then around 10:00 AM, my instructor called, asking whether I'd be interested in flying through some clouds. Sure! I finished my breakfast, took a quick shower, put on the "nice clothes" I'd need for a family get-together later in the afternoon, and headed for the airport.

Here's a little background info on instrument flight for non-pilots: When an airplane turns, you don't feel yourself tilted from side to side; instead, you just get pushed straight down into the seat. Level flight, a left turn, and a right turn all feel the same. The organs in your ears that sense motion aren't very accurate (for a demonstration, close your eyes, spin yourself in a chair, then try to stand up). Your sense of motion is very helpful when you can also see what's happening, but when you can't see the ground, you can't fly by feel, you have to use the instruments. In fact, your feelings will mislead you, so you have to learn to ignore your instincts and trust the instruments. Studies show that non-instrument-rated pilots who lose their view of the ground will invariably go into a "graveyard spiral" in a matter of minutes, and never know it. The FAA requires a minimal amount of instrument training, so that pilots who inadvertently wander into clouds or fog can safely turn around and get out.

"Instrument Meteorological Conditions" (IMC) refers to weather that requires operation under Instrument Flight Rules (IFR). Pilots usually train using "simulated IMC," meaning that they wear a hood, Foggles, or other device that restricts the view outside the plane but allows viewing of the instruments. Actual IMC experience is a lot more valuable. I know my instructor's ulterior motive for calling me today was to be able to get the experience for himself, but I'm glad he did.

I'll confess that this is the first time I've felt the least hint of danger while flying. I wasn't really worried, but as the ground disappeared completely a few seconds after takeoff, it occurred to me that in the unlikely event that my instructor became incapacitated, I would have no chance of landing the plane safely myself. There was also the possibility that I'd do something stupid that the instructor wouldn't catch soon enough. But these were just passing thoughts. I know my mother reads this blog, so I have to stress that there was nothing dangerous about this. The experience will make me a safer pilot.

At first, it was eerie. I could see the wings of the plane clearly, but there was nothing but a bright white background surrounding us, like being in the center of a ping-pong ball. Believe it or not, you need sunglasses in clouds, as the whiteness can really strain your eyes. At our assigned altitude of 4,000 feet, we were skimming the top of the cloud layer. We'd see up into the sky for a minute or two, then be back in clouds for a few minutes, then out again, and so on. Flying a few feet over the clouds is definitely the coolest thing I've seen so far. Unfortunately, I didn't have much time to enjoy the sights, as my eyes were riveted to the instrument panel.

The instructor had filed a flight plan to perform a hold over a fix about ten miles north of the airport. This means we flew a few laps in a racetrack-style circuit, using VOR/DME equipment to determine our position and distance to the airport, and using a timer to keep our pattern the right size. The instructor told me the headings to fly, when to turn, and so on, while he handled the radio, the navigation equipment, and the timer.

The attitude indicator was acting a little strangely, always showing a bit of a bank even when the other instruments indicated we were level. The instructor declared it "inop" (inoperative) and covered it up. Inoperative instruments get covered up so that they won't confuse the pilot.

I did a pretty good job of holding altitude, but wasn't so good on holding the headings. With the attitude indicator gone, I had to rely on the turn coordinator to maintain wings-level. When the turn coordinator shows a slight bank, I often make the wrong correction: the reason is that the instrument shows the plane tilting, but I sometimes think of it as the horizon tilting (like the attitude indicator), so I start banking the wrong way until I notice that the bank is getting worse or that the heading indicator is spinning in the wrong direction. Aside from that, I did better than I have before at continuously scanning all the instruments, including an occasional glance at the outlying instruments that aren't part of the "six-pack" of primary instruments. It's a lot easier to keep track of everything going on in the plane in actual IMC than it is one's peripheral vision is obscured by a hood or Foggles in simulated IMC.

We were tuned to Atlanta Approach control throughout the flight. There was continuous conversation, which was very different from the silence I'm used to when flying in the local practice area. It was difficult to communicate with the instructor with all that other chatter going on. I'll get more experience with this when I do my cross-country flights.

After a few laps, we flew the ILS (Instrument Landing System) approach. I didn't know much about this, so the instructor did most of the flying, letting me have the controls every once in a while when things were stable. When making an instrument landing, there is a "decision height" at which you have to be able to see the runway, or you must abandon the landing. It was spooky seeing nothing but whiteness all around, watching the altimeter drop, not knowing when or if we'd see the airport, but eventually the ground appeared, and we had the runway in sight just about 100 feet above the decision height.

So, it was a great experience. I know I probably won't get another chance to fly in actual IMC until some time in the future when I go for an instrument rating. Many private pilot students never get such a chance.

For today: 1.0 hours dual in N4332L, including 0.8 hours of actual instrument flight. No takeoffs or landings for me. Cost: $197.83.


Comments:
So what you're saying is that Obi Wan was full of it when he put the blast shield down on Luke and told him to 'trust his feelings'!
 
So what you're saying is that Obi Wan was full of it when he put the blast shield down on Luke and told him to 'trust his feelings'!
 
So what you're saying is that Obi Wan was full of it when he put the blast shield down on Luke and told him to 'trust his feelings'!
 
sorry - blogger was returning errors when trying to post. didn't realize it went ahead and posted those comments each time. feel free to delete if you can
 
We always heckle that scene with "use the flight director, Luke!"
 
I'm glad that you got some actual IMC practice during your PPL training -- hopefully, you'll get a lot more when you start your instrument rating later on.

That said, I'm a little concerned about this particular lesson. I'm reluctant to second-guess your instructor, but while partial-panel work under the hood is fine, you were in actual, low IMC, and loss of the attitude indicator was a bona fide emergency. If the instructor really thought it had failed, you should have declared an emergency and returned to the airport immediately, because you no longer had any redundancy -- if your turn coordinator failed (say, because of an alternator problem), how would you have kept the wings level?

Redundancy is what keeps us alive in our planes, and losing redundancy is a very serious business. It might be worth having a polite talk about this lesson with both your instructor and the chief instructor at the school -- perhaps your instructor didn't really think the AI had failed (a bit of a tilt isn't uncommon with old, worn gyros) and just wanted to simulate the situation for you.
 
The attitude indicator was not completely failed, it just wouldn't go perfectly vertical.

He did uncover the attitude indicator when it was time to return for landing, so I think he was just helping me by making me use an instrument with less lag to monitor bank. I will ask him about it.
 
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