FAA Redefines Slow Flight and Stall Procedures

Agency considered industry feedback in recent ACS changes.

By Rob Mark June 8, 2017

With loss of control still the primary cause of aircraft fatalities, the FAA last year released the new Airmen Certification Standards, some aspects of it controversial, to replace the practical test standards for pilots seeking a private or an instrument rating. The goal was to create a better-trained pilot before they appeared for their flight test. Last week, the FAA released changes to the standards after considering industry feedback.

The new safety alert for operators — 17009 — incorporates updates to the Private Pilot-Airplane and Commercial Pilot-Airplane ACS, both of which become effective on June 12. The new guide looks specifically at how designated pilot examiners will be expected to evaluate applicants during slow flight and stall-related maneuvers.

Considering that slow flight is normally performed close to the ground, the topic was hotly debated last summer when the ACS first appeared.

The agency believes applicants must become proficient in slow flight through practice at a safe altitude, while also mastering an understanding of the aerodynamics associated in various aircraft configurations and attitudes. Training must include recognizing aircraft cues and smoothly managing coordinated flight while maneuvering without sounding a stall warning alert.

If the stall warning should occur, the applicant is expected to make a prompt and appropriate correction. The FAA believes the desired slow flight characteristics can be learned while climbing, turning, descending and performing straight and level flight again, all without the stall warning blaring.

The FAA maintains that a pilot should not be evaluated on the ability to maneuver an airplane in slow flight while disregarding a stall warning, however. To address community feedback, the FAA modified the phrasing of the requirement to read: “Establish and maintain an airspeed at which any further increase in angle of attack, increase in load factor, or reduction in power, would result in a stall warning.”

The agency believes stall training should build on knowledge and skill acquired from slow flight maneuvers and cover the period from the initial stall warning to the actual stall. Pilots are expected to understand stall aerodynamics in various aircraft configurations, attitudes, and power settings, as well as how the airplane performs/responds as it approaches the critical angle of attack.

Pilots must also understand factors that lead to a stall, as well as how to prevent them while recognizing the appropriate airplane cues in both impending and full stalls. Under this change to the ACS, the applicant will now be required to clearly acknowledge (verbally) aircraft stall warnings whether it’s the buffet or a warning horn and be prepared to successfully demonstrate a complete stall recovery procedure.

The new document shows the agency held fast to the commercial standards first released last year, such as recovery from accelerated stalls in a multi-engine aircraft, but showed flexibility when it came to recovery from power-on and power-off stalls. Initially, the agency wanted to see applicants initiate a full stall recovery at the first indication of the loss of lift, no matter what. After considerable industry criticism, the agency eventually modified the language to read, “Acknowledge the cues and recover promptly at the first indication of an impending stall (e.g., aircraft buffet, stall horn, etc.).”