Friday, May 27, 2005

 

Flying Lesson #26: Spin Training

Today we did spins. What's a "spin," you ask? I'll give a drastically simplified non-pilot explanation (if you really want to understand it, there are plenty of other sources). First, we need to know what a stall is. A wing generates lift when air is flowing around it in the right way; a stall is a situation where the wing stops generating lift because the air is not flowing around it correctly. Stalls typically happen when an airplane is flying too slowly or turning too steeply. When an airplane stalls, it stops flying and starts plummeting. A spin is a situation where the airplane is stalled, and one wing is stalled worse than the other, causing the airplane to fall in a corkscrewing path. Once a spin starts, the airplane tends to keep spinning, so it can be difficult or even impossible to recover.

A significant percentage of General Aviation accidents are the results of stalls and spins. All pilots are required to practice and demonstrate stalls, not because stalling is a useful maneuver, but because all pilots need to recognize when a stall is imminent or in progress, and they need to know how to recover safely. While everybody practices stalls, many flight schools don't give their students any experience with spins; see this article for some explanation of the controversy between pro-spin and anti-spin instructors. My flight school requires all students to have training in spin recovery before they solo, and I'm glad that they do.

The preferred way to do spin training at my school is to go up with the chief flight instructor in the school's Super Decathlon, a fully aerobatic airplane. Unfortunately, the combined weight of the chief instructor and me would be about 20 pounds over the limit. We're not so huge that the airplane can't lift us; the problem is that the center-of-gravity of the plane needs to be within a narrow range for safe aerobatic flight. (I've been hoping to get aerobatic training someday, so I guess it's time to start losing weight.)

The Decathlon was not an option. The Piper Warriors that I usually fly are not certified for intentional spins, so we flew in the school's Cessna 172N. This was my first experience with the Cessna. Here's what I liked about it in comparison to the Warrior:

And here's what I didn't like about the Cessna:

The instructor did all the weight-and-balance calculations to ensure that we were safe to do spins. To minimize weight, we left our flight bags behind and got into the plane with only our headsets and kneeboards. The instructor let me taxi to the runway, and I zig-zagged the whole way because the Cessna's steering is very sensitive in comparison to the Warrior.

Once in the air, I did a lot of turns to get a feel for the plane. We climbed up to 7,000 feet, so I got a much bigger view of the area than I normally get down at 3,500. I did a couple of stalls to get used to the Cessna's stall characteristics. Then, it was time to do the spins.

The instructor performed the first one. A Cessna 172 doesn't really want to spin, so it takes some work to make it happen. The procedure is to slow down to 60 knots, then go to full power and climb while using full right aileron and full left rudder. The effect is that the plane goes almost straight up while twisting a little, then suddenly the nose drops toward the ground and the plane starts spinning rapidly. After a couple of rotations, you're in a full-blown spin.

I didn't know what to expect. The instructor had warned me that lots of people throw up or have other kinds of distress, so I was expecting some intense roller-coaster-style sensations. It really wasn't too bad. I can certainly see how it would freak someone out who wasn't expecting it, and it would be terrifying at a low altitude, but up at 7,000 feet with an instructor sitting next to me, it compared to some of the tamer rides at Six Flags.

In ground school, you learn that the steps for recovering from a spin are to reduce throttle to idle, neutralize the ailerons, use full rudder opposite to the direction of spin to stop the rotation, pitch the nose down sharply to break the stall, then recover. Things didn't work quite that way in the 172. When the throttle is cut and the ailerons are neutralized, the plane stabilizes itself very quickly. At that point, you are in a steep dive, so you just pull out of it and it's all done. There's not much need for opposite rudder or downward pitch.

After the instructor demonstrated one, I did a few (I lost count). On a couple of attempts, I couldn't get it to "go over," instead ending up with just a stalling steep turn. The secret to getting it to work right was to gradually add the aileron instead of going to full aileron instantly.

On one attempt, we got to a full 90-degree-pitch climb, which is probably the closest I'll ever come to being an astronaut.

I was a little slow on cutting the throttle during the recoveries, so we were often going straight down very fast. It wasn't dangerous, but pulling out of those dives caused my instructor to groan a little. I'm wasn't sure if he was groaning due to the G-force or due to displeasure with my performance. (During the debriefing, he said it was a little of both, but no big deal.)

Each spin itself only lasted a few seconds, but between each attempt we had a few minutes of climbing back to a safe altitude and doing all the typical pre-maneuver activities. At around 3:00, the instructor said, "OK, we only have time for one more." I knew he was lying: we didn't really have time to do it again and get back to the airport before his next scheduled lesson, but he was enjoying it as much as I was. So we did one more and then headed home.

In summary, it was all a lot of fun, and a lot less scary than I expected. Days like this really boost my confidence. While flying I'm often afraid I'm going to bank a little too far, fly a little too fast or a little too slow, land a little too hard, or make some other minor mistake that will lead to disaster. It eases my concerns when I see how the airplane behaves in extreme circumstances and know I am able to handle it. I think it's a shame that many instructors avoid teaching this stuff.

Logged today: 1.6 hours dual in N739DB. Cost: $289.73.

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Comments:
a nice 'laymans' explanation of how it feels to learn to fly and spin training. i recon i,m about at the same stage of instruction as you and its nice to know i,m not the only one who is having a coronary every two mins in case i mess up! happy flying mate
 
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