The Airman Certification standard (ACS) replaced the Practical Test Standard (PTS) for the certification of private (and instrument) pilots as of June 15th this year. The primary thrust of this testing transformation was to update the knowledge testing questions and philosophy, replacing ancient, irrelevant test questions in the data bank with more timely, calibrated questions correlated to the areas of operation in the flight test. The intention (and some involved parties say “FAA promise”) was to not modify the flight test maneuvers or completion standards during this process. It does appear though that on the way to the alter, one critical vow was transformed and quietly embedded into the new ACS. Now that it has been discovered, this slow flight modification is creating quite a dust-up in the flight training community.

Doug Stewart in Flying Magazine; “Prior to the ACS, the PTS specified slow flight as ‘an airspeed at which any further increase in angle of attack, increase in load factor, or reduction in power would result in an immediate stall,'” Stewart said. “The ACS now specifies slow flight as, 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.”

The new FAA SAFO highlights this controversy and presents the FAA position. The FAA does not want pilots in training flying with the stall warning horn blaring with the supposition this will lead to ignoring this critical warning device. [FAA ACS FAQ] This new FAA focus developed directly from accidents such as the Colgin 3407 crash in Buffalo, where the pilot decelerated rapidly into a high AOA configuration and aggressively held the plane in an aggravated stall defeating the stall protection safety devices and resulting in 50 deaths. To me this seems like a one off pilot error more than a symptomatic problem with the entire flight training process. From the Wall Street Journal May 11, 2009;

The captain of a commuter plane that crashed Feb. 12 near Buffalo, N.Y., had flunked numerous flight tests during his career and was never adequately taught how to respond to the emergency that led to the airplane’s fatal descent, according to people close to the investigation.

Capt. Marvin Renslow had never been properly trained by the company to respond to a warning system designed to prevent the plane from going into a stall, according to people familiar with the investigation. As the speed slowed to a dangerous level, setting off the stall-prevention system, he did the opposite of the proper procedure, which led to the crash, these people said.

Practicing and demonstrating pilot knowledge, skill and control in this slow flight area of airplane operation is critical to flight safety and is the holy grail for most CFIs and DPEs. There is great training value in mastering (and regularly practicing) slow flight with the stall warning horn operating, coordinating your plane carefully at the maximum angle of attack right up to the aerodynamic stall. The FAA’s own 1976 FAA Stall Awareness Study clearly demonstrated that “extra stall and slow flight training was effective in preventing unintentional spins.” Inflight-Loss Of Control is the major causal factor for fatal accidents in aviation so understanding and controlling this phase of flight is critically important to pilot safety. If a pilot never experiences and trains in this critical phase of flight their reaction might be an inappropriate panic response like Cpt. Renslow.

Send your comments supporting retaining slow flight in it’s previous (slower) form as an essential part of flight training to the ACS focus team at the FAA Aviation Working Group. Please mention your flight training experiences and viewpoints. They meet on September 14th (that should be an interesting meeting…) Have fun, fly safely, and best wishes for a wonderful holiday weekend.

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