Pegasus Aviation Service, LLC

Minimum Controllable Airspeed BACK to Index

DescriptionThe airplane is maneuvered at minimum controllable airspeed (MCAS) - which is the airspeed in which any further increase in angle of attack, increase in load factor, or reduction in power, would result in a stall. This maneuver should be accomplished in straight flight, turns up to 30° of bank, climbs and descents using various flap configurations. ObjectiveTo teach the student to recognize changes in airplane flight characteristics, sight picture and control effectiveness at critically slow airspeeds in various configurations while maintaining positive airplane control at all times. The student will NOT be tested on this maneuver during their FAA checkride. For checkride prep see: Maneuvering During Slow Flight. Procedure• Complete pre-maneuver checklist. Clear the area. Make radio calls as appropriate. Maintain 2300 RPM and approximately 90 KIAS. Choose an outside visual reference.• Decrease airspeed. Apply carburetor heat, reduce power to 1500 RPM and gradually increase back pressure on yoke to maintain altitude. As airspeed decreases, more right rudder will be needed to maintain coordination. Trim to relieve control pressures.• Stabilize at minimum controllable airspeed (MCAS). Once (85 KIAS) is reached, set flaps to 40° in increments (or as desired). As flaps extend, adjust pitch attitude and increase power to maintain altitude at MCAS – with stall horn audible. Trim to relieve control pressures. Note sight picture needed to maintain altitude with stall horn audible.• Preform a climb. To climb, increase power and turn carburetor heat off as necessary. Consider retracting flaps if needed. Pitch should be adjusted to maintain MCAS– with stall horn audible.• Perform a descent. To descend, reduce power and adjust pitch to maintain MCAS– with stall horn audible.• Perform shallow turns. Turns should be performed to specified headings as normal but note the soft and “mushy” feel of the controls as less air is moving over the control surfaces. Additional power may be needed to compensate for the reduction in the vertical component of lift.• Return to cruise flight. Turn carburetor heat off and apply full power. While maintaining heading and altitude set the flaps to 0° in 10° increments. As the airplane accelerates, pitch attitude should be reduced, and less right rudder should be used to maintain coordinated flight. As cruise airspeed is reached, reduce power and adjust trim to relive control pressure. ACS Standards• N/A