Maneuvering during slow flight is a task required of all private pilot airplane applicants per 14 CFR §61.107(b). The applicant must be able to demonstrate this task to a set of evaluation standards outlined in the Airman Certification Standards (ACS-6). The Private Pilot ACS, effective June 15 2016, revised how slow flight should be conducted during the check ride. Additionally, to support this change the FAA released a Safety Alert for Operators (SAFO) to reiterate those changes including the logic behind them. You can view the complete SAFO below:
Slow flight was previously taught and evaluated as outlined in the Practical Test Standards (PTS) by flying at an airspeed where any further increase in angle of attack, increase in load factor, or reduction in power, would result in an immediate stall. This often lead to the stall warning being activated throughout the entire maneuver, yes that blaring horn that says, “hey you’re about to stall, do something about it!” Maneuvering with the stall warning activated can promote negative learning—it’s never a good idea to ignore a warning system—the FAA says this was “neither desirable nor intended.” This specific evaluation standard is now changed to read:
Establish and maintain an airspeed, approximately 5-10 knots above the 1G stall speed, at which the airplane is capable of maintaining controlled flight without activating a stall warning. (PA.VII.A.S2)
This now allows the pilot applicant to maneuver without the stall warning continuously being activated during slow flight. He/she will still assimilate the same fundamental concepts and skills of operating an aircraft at slow airspeeds like during departure and landing.
Establishing Slow Flight
To establish an airspeed 5-10 knots above the 1G stall speed:
- Reduce power and progressively raise the nose to maintain altitude until the stall warning sounds and note that airspeed;
- pitch down slightly to eliminate the stall warning;
- adjust power to maintain altitude and note airspeed required to perform slow flight maneuver (a few knots above stall warning speed);
- note the position of the control column and the force you are having to apply; and then
- retrim and balance.
As you note in the first step the pilot applicant is actually momentarily pitching for an airspeed in which the stall warning will activate. This allows the pilot to determine the stall warning speed and then pitch for an airspeed slightly above it (2-3 knots). For example if the stall warning activates at 55 knots an acceptable speed to perform slow flight would be 57 knots. Further evaluation standards allow for airspeed variances of +10/-0 giving the pilot an acceptable airspeed range of 57–67 knots.
The FAA is further working on removing inconsistencies found between documents particularly the Airplane Flying Handbook to better align the slow flight maneuver with the new standards outlined in the ACS. The next time you head out to conduct slow flight make sure you take a look at the ACS to completely understand the required standards for the task.
