Impossible turn: Practice makes possible?

May 19, 2011

Less than one minute after takeoff, my Cessna 172’s engine sputters and quits. My heart is pounding as I bank hard left and turn back to the airport—a move that has proven disastrous to many other pilots.

Impossible Turn maneuver checklist

  1. Set up on a cardinal heading.
  2. Climb halfway between Vx and Vy.
  3. Pull the throttle to idle at a pre-established altitude.
  4. Hold the same climb pitch for five seconds.
  5. Roll into a 45-degree bank turn.
  6. Pitch for best glide speed.
  7. Turn 270 degrees into the wind.
  8. Roll wings level.
  9. Simulate a flare to stop the sink rate.
  10. Note altitude lost.
  11. Add 50 percent of the altitude lost for a safe cushion.

Thankfully, this is a practice scenario at 4,000 feet msl with my instructor Sandy Geer, the chief flight instructor at Frederick Flight Center near AOPA’s home base in Maryland. I’m trying out AOPA Pilot Contributor Barry Schiff’s steps for the so-called impossible turn so that I’m prepared to make an informed land-straight-ahead or turn-back decision if ever presented with such an emergency. In his article, Schiff notes that he’s turned back after an engine failure, and the aviator in this Real Pilot Story did so as well, while a video camera installed in the aircraft captured the event.

The key to Schiff’s approach is to find out how much altitude you need to turn around safely—not to try to turn the aircraft around in a pre-set amount of altitude.

Applying full power, I climb from 3,500 feet to 4,000 feet msl between best angle and best rate of climb before pulling the throttle to idle. Then, with my airspeed bleeding off and the stall horn starting to blare, I struggle to maintain that same pitch-up attitude for five very long seconds, hoping the aircraft doesn’t stall. Why hold the attitude? Schiff says it will take about five seconds to recognize and react to the real emergency, so this time delay will help achieve a more accurate re-creation.

I then roll into a 45-degree bank, letting the nose naturally fall through the horizon to reach best glide speed and then applying back pressure to maintain it. Even at altitude, I forget to re-trim the aircraft to make the steep bank easier—a good indication that the same would be true in a real emergency close to the ground. Finally, I pull out of the descending steep turn with an altitude loss of 300 feet after turning 270 degrees.

"Continue the turn for 270 degrees because reversing course to the runway requires more than a 180-degree turn. A 180 only places the airplane parallel to the runway and displaced to one side," Schiff counsels. "Forty-five degrees of additional turn are needed to return to the runway centerline, and then another 45 degrees to line up with the runway. This means that roughly 270 degrees (180 plus 45 plus 45) are needed to return to the runway."

Would I have been safe to actually perform the maneuver within that amount of altitude? Not after this first practice round. While I completed the maneuver within 300 feet three times, once I lost 500 feet because I didn’t maintain best glide speed. Allowing the aircraft to descend just five to 10 knots faster than best glide added 200 feet. The other kicker: I looked inside the cockpit the entire time, focusing on the instruments. That won’t work in an actual emergency.

But practice is key. With regular practice at altitude to memorize the maneuver, establish a consistent pitch attitude, and look outside, I might turn back at a lower altitude than I would otherwise. My turn-back altitude for a Cessna 172 has always been a minimum of 1,000 feet. With practice, I might try it at 750 feet if the area ahead of me were filled with obstacles. At least now I have a better reference point to make a decision in the event of an unexpected engine failure on takeoff.