Vintage Instructor THE
BY DOUG STEWART
Between a rock and a hard spot In last month’s article I wrote about flying on the backside of the power curve. So just as a refresher in case you didn’t get a chance to read it, the backside of the power curve exists whenever there isn’t sufficient power to overcome the induced drag created by high angles of attack. Anytime we fly in slow flight, we are most often on the backside of the curve. In this regime, you will notice that if you increase back pressure on the stick, the houses actually get smaller rather than bigger. This is why it’s known as the area of reverse command. And of course if we continue to pull on the stick, or yoke, the airplane will reach its critical angle of attack, and if that angle is exceeded the airplane will stall. To add insult to injury, if we haven’t added sufficient right rudder to compensate for all the left-turning tendencies occurring in this attitude, when the airplane stalls, it will most likely spin. For many pilots this area of flight is rarely experienced, except on practical tests or on flight reviews. I don’t know many pilots who go out and practice flying as slowly as they can, but I personally love to go up in my PA-12 when the winds aloft are blowing at more than the stall speed of my Super Cruiser. I then pull the power back until I am just hovering in place, and chuckle to myself as I think of the terminal radar approach controllers (TRACON) wondering about what visual
22 JANUARY 2009
flight rules (VFR) aircraft is hovering at 5,500 feet. However, there are certainly times when we might very well have to fly the backside of the power curve, not to confuse a controller, but to achieve a specific task. Ask any bush pilot to describe his technique for landing on a very short landing strip, especially when it is surrounded by obstacles, and he will explain his method as being on the backside of the power curve, balancing pitch and power to keep them on a steep glide slope at slow speed. This is the technique I had to use landing at a 1,900-foot runway (not that that is very short) in the hills of New Hampshire this past summer. It was the end of August on what was perhaps one of the most beautiful days of the year. The temperature was in the mid-70s, the air was smooth with light and variable winds on the ground, and the high pressure helped to create visibilities that don’t get much better, especially in New England. My best friend and I flew up to visit a retired FAA safety program manager and his wife. He has been my mentor and role model not only in aviation safety, but in life as well. We had a wonderful visit, and I was thinking that this had been the best day of the summer for me. All too soon, though, the time for departing arrived. Driving back to the airport, we meandered on a dirt road, through
rolling hills and thick forest, and then suddenly emerged at the airport. The only real indication that we had transitioned to an airport was a windsock, a couple of hangars, and my parked Cardinal RG. Although the runway had been dirt for many years (and really was a continuation of the dirt road), it was now paved with asphalt. It also was not flat, but had a gentle rolling contour similar to the end of a roller coaster ride. The airport narrowed toward the departure end, with rising wooded terrain on both sides, and trees at both ends. (This sure isn’t Kansas, Toto!) At least the density altitude wouldn’t be an issue, what with the moderate temperature, high pressure, dry air, and a field elevation of only 510 feet. The windsock indicated light winds at about 3 knots, favoring a departure to the southwest. The winds wouldn’t be of much help, especially in clearing the trees, but it was better than having no wind at all. After a thorough preflight inspection, we bade our gracious hosts a fond farewell and fired up the Cardinal. After an uneventful run-up and completing the before-takeoff checklists, we taxied to the very end of the runway. Holding the brakes, I applied full power and confirmed that we had the proper manifold pressure, rpm, and oil pressure prior to releasing the brakes. As I looked down the runway I noticed two people walking toward us on