P&E PROFICIENCY The mix-you-up valve Beware the break in a cross-controlled stall BY JOHN CARROLL RENEW YOUR CFI CERTIFICATE WITH THE AOPA AIR SAFETY INSTITUTE THE AIR SAFETY INSTITUTE IS THE ONLY FIRC PROVIDER THAT PUTS 100 PERCENT OF ITS REVENUE BACK INTO GENERAL AVIATION SAFETY EDUCATION ONLINE * Complete the eFIRC on your time * Videos and Interactive lessons * New modules * 10 electives to choose from I HAVE LEARNED TWO THINGS about flying over these many years. One is that aircraft instruments are designed to point out with ever-greater accuracy what you are doing wrong. The other is that every aircraft has two sets of controls: One set has a direct linkage to the aircraft surfaces and answers to your every command. The other system doesn't answer to anyone. No mechanic has yet been able to find this second system. It remains one of the great mysteries of aviation but must be hydraulic in nature because it seems to be equipped with a standard issue mix-you-up valve. This second system doesn't cost any extra money; is mandated by the nature of aerodynamics; and is most active in slips, skids, and stalls. Most pilots encounter the second system for the first time while doing a cross-controlled stall in a turn. Student pilots learn early on that a properly coordinated turn involves the use of rudder and aileron in the same direction. Ailerons are designed to roll the aircraft into a bank where the wing can be used both to hold the airplane up and to pull the aircraft to one side. But because of the tendency to overbank because of the greater lift coming from the outside wing, it is normal for a pilot to apply opposite aileron while executing a turn to hold the bank angle steady. If the pilot maintains rudder pressure in the direction of the turn and applies enough opposite aileron, we would call that being cross-controlled. The mix-you-up valve would call that same condition game on! Let's say that you're about to stall in a turn and are applying top instead of inside rudder. The stall will break in the direction the yaw is coming from, regardless of bank angle. So, the lower wing will go up and over the top of the turn as the nose falls after the break. Unless you have been briefed beforehand, aopa.org/pilot AOPA PILOT | 91 * The best customer service assistance * Only $124 IN-PERSON * Skip the FSDO trip with online paperwork * Network with other CFIs * Best presenters in the industry * Preregister Only $275 RENEW WITH THE BEST! Visit www.aopaFIRC.org to sign up today. Save on your Flight Instructor Refresher Course with the new AOPA World Mastercard® Visit www.aopa.org/creditcard Funded in part byhttp://www.aopaFIRC.org http://www.aopa.org/creditcard http://www.aopa.org/pilot