by Michael Kaufman
This is the third article in a continuing series I have been writing on “autopilots.” Since beginning this series, I have encountered more issues with malfunctioning autopilots than in the previous 40 years I have been flying with them. Some of these issues were mentioned in previous articles, except for those of Galen Manternach and Dr. Scott Heun, both flight students and customers of mine. I recently finished Scott’s instrument training in his Bonanza, and he needed to do his checkride without any assistance from “George,” a term often used to describe flying on autopilot.
This article is on “flight directors,” and how to properly use them. I will put an emphasis on the King KFC200 autopilot with flight director, because there are so many of them flying in the field, but many others have similar features. Most of the pilots that come to our Beechcraft Pilot Proficiency Programs (BPPP) who have flight directors, do not know how to properly use them. In fact 80 percent do not. The remaining 20 percent who do are mostly professional pilots.
In the professional pilot world, pilots refer to flying an approach in three ways – “autopilot,” “flight director,” and “raw data.” Let me explain.
The autopilot is the easiest to understand, and I will not further address this method. Using the flight director, which is misunderstood by most, means that the pilot is hand flying the aircraft with the assistance of the flight director. In other words, the pilot is using his eyes to interoperate what the flight director is telling him, and he is using his muscles in place of the autopilot servos. The third method, which is known as “raw data,” has the autopilot and flight director off, and the pilot is interpreting what he sees on his horizontal situation indicator (HSI) or course deviation indicator (CDI), and making the necessary corrections.
The flight director method requires that the flight director is turned on, but the autopilot (servo mussel) remains off. The pilot then selects what he wants to do via the available modes. An example of this would be flying radar vectors to join the final approach course using the flight director and “GPS assist” from a Garmin 430 on the King KFC200 autopilot with flight director, but other autopilots with flight directors have similar functions.
First, we must load the ILS approach and set the localizer frequency in the active window on the Garmin 430, followed by “activate vectors to final.” The flight director mode is selected on the autopilot, along with heading and altitude in the aforementioned order. The flight director should then “Q” the pilot on what to do via the command bars. It needs to be noted that if the aircraft is equipped with “GPS steering,” that the selector should be in the heading mode. At this point, the pilot should use his heading bug to select the heading assigned by ATC and adjust it as new vectors are received. Shortly after the first vector for the approach is received from Air Traffic Control, pushing the heading and approach button on the autopilot simultaneously should get both the heading and approach lights illuminated on the autopilot display, along with the “arm” light. If you did not satisfy the autopilot by being exact when simultaneously pushing the buttons and the heading enunciator is not on, just push the heading button again to get the proper response on the autopilot enunciator. What you have told the flight director is that you want to fly the heading on the bug and the altitude you currently have until you intercept the localizer course, at which time the heading light and armed light will extinguish and the coupled light will come on. Once we capture the glideslope, the altitude light will extinguish and the glide slope light will come on, followed by a pitch down indication on the flight director command bars.
There are a lot of safety features built into the operation of flight directors and autopilots. A comment I hear quite often is that the autopilot does not always capture the glideslope. So this is what usually causes the problem: the controller vectors you in too tight and too high on the approach to allow the glideslope capture. When the arm light extinguishes and the coupled light comes on, a timer circuit is activated. If the glideslope is intercepted before the timer cycle is completed (20 to 30 seconds), the glideslope will not capture.
Radio signals have false courses or unwanted signals that are a byproduct of the localizer and glideslope signals. The manufacturer does this to eliminate accidents caused by this phenomenon (see insert from the AIM on localizer structure). Dr. Scott Heun learned the importance of monitoring the enunciator panel for the proper indication during his training as we ended up losing the servo or muscle part of the autopilot part way through his training, but the flight director portion continued to function. Scott did a great job even with this handicap. Congratulations, Scott, on a job well done and an instrument rating now in your pocket!
A flight director can be of great assistance to a pilot during other critical portions of flight as well. For example, takeoffs and go-arounds. Some autopilots have a GA (Go Around) button located on the control yoke or, in some cases, the throttle. When reaching the DH (Decision Height) or MAP (Missed Approach Point), the pilot may execute the missed approach by pushing the GA button. This disconnects all of the autopilot functions except the command bars, which pitch up to the recommended climb angle that is pre-set for each individual aircraft by the manufacturer. The pilot may then select optional functions like heading or navtrac that will direct the pilot to the MAP. By turning on the autopilot switch, the servos will provide the muscle to fly the aircraft once properly set up. Many pilots use the GA function for a take-off, setting the departure path and pitch angle prior to beginning the take-off roll.
Some autopilots with flight directors have a CWS (Control Wheel Steering) button located on the yoke. This button may be used to temporarily disconnect the flight director for the pilot to make small corrections to altitudes or set a path for a descent angle on a non-precision approach. I find most aircraft (75%) have either the GA or CWS button, but not both. Dr. Heun’s Bonanza was fortunate to have both.
I find it fun to teach pilots how to use their flight directors and often cover up the HSI with a “no-peekie,” and have them hand fly an ILS approach using only the attitude indicator/flight director bars and the altimeter to give them the decision height. A pilot can learn a lot from his or her flight director and can master it with usually just a few approaches. If you want proper training on the flight director, I will be happy to work with you when I am not doing a BPPP clinic.
My next column on autopilots will cover GPSS or roll steering that has become the standard of instrument flight. Till then, fly the command bars on your flight director and enjoy a new skill.
EDITOR’S NOTE: Michael “Mick” Kaufman is the manager for the Beechcraft Pilot Proficiency Program and a flight instructor operating out of Lone Rock (LNR) and Eagle River (EGV), Wisconsin. Kaufman was named “FAA’s Safety Team Representative of the Year for Wisconsin” in 2008. Email questions to email@example.com.