The Magical Flight Director
New to using a flight director? Get more detail on the benefit of using it and how you can work it in to your flying routine!
In general, students transitioning to the G1000 equipped with Garmin’s GFC700 (Automatic Flight Control System) are experiencing their first exposure with a wonderful bit of technology. Sadly, many (including Garmin) refer to the GFC700 as an autopilot. In reality, only one button on the GFC700 panel relates directly to autopilot and that is the “AP” button. Hmmm, so what are the other eight or nine buttons for?
Glad you asked. These buttons are for the Flight Director. So, what is the difference between a Flight Director (FD) and Auto Pilot (AP)? Simply stated, the FD provides a guide that compares actual flight path with intended flight path. The AP, using servos, follows the Flight Director (FD). A simple analogy - the FD is an electronic brain and the AP is the muscle and nerves that implement the FD instructions. Using this analogy, it is your best backup of what you want to do when properly configured for each task AND assists you by providing a reference marker (Command Bar) on the PFD to accomplish your intended flight path objectives.
Hmmm, another question please. “Why do I need the FD if I only want to hand fly the airplane?” I’ll partially counter by asking if you would like a tool that supports your hand flying intentions AND allows hand flying to be more relaxing and rewarding.
As aviators, we are taught, with good justification, to confirm every action taken. This includes confirming departure runway, initial climb attitude and heading, final altitude, altitude hold, etc. Wouldn’t you like a tool at your disposal that simplifies your achieving these goals? If yes, welcome to the Flight Director.
The initial reaction by many when introduced to the Flight Direction (FD) is, “Oh I’m not going to set up the FD because I’m hand flying.” The Flight Director is your key to a more rewarding and relaxing hand flying experience. Why, because it is a single source of confirmation for heading, attitude, and roll that correlates what you are actually doing in flight with what you want to do.
The front end for the flight director is the FD Command Bar on the PFD. The Upper inverted (magenta) V is located center screen at the horizon line. The lower, inverted (yellow) V is the aircraft symbol which represents what the aircraft is actually doing. When your flying skills are in harmony with expectations, the aircraft symbol is in sync, under the Command Bar. Any deviation of the aircraft symbol from the FD Command Bar is corrected with slight adjustments as needed to reposition the aircraft symbol under the Command Bar.
So, how can the FD assist you? You’re on the ramp, have done the initial engine check, received weather and hear that runway 18 is in use for arriving/departing aircraft. Some of your usual next steps are to set your barometric pressure and mentally confirm you are taking off to the South. Now would be a great time to double check yourself. Set your Heading Bug for 180 and press HDG on the GFC700. It will begin to indicate you need to orient the airplane to the South. (Not taxi South! )
You complete your taxi and engine runup, and contact tower for departure release. Tower advises you to fly runway heading to an initial altitude. Set your initial altitude and press Go Around (GA) (this is Cessna terminology). (Note: this does not enable the AP. In fact, if the AP is operating, pushing GA will disable the AP.) Pressing GA does instruct the Command Bar to a establish a 7.5 deg nose up attitude (climb) relative to the horizon AND establishes wings level attitude. You are released. Power up, depart and allow the Command Bar to assist you in maintaining wings level and 7.5 deg nose up. You are still hand flying but with an assistant. Cool eh? This 7.5 deg climb gradient at full power will not allow you to stall the aircraft – assuming you have done all the necessary determinations of weight, balance, density altitude, etc at takeoff.
You have departed and flown runway heading to an altitude when tower tells you to contact approach. Approach confirms contact and directs you to a new heading of xxx degrees and climb to xxxx’. You turn the heading bug to that heading and set your new altitude. The FD will begin showing a roll in the correct direction. Follow this and you will make a standard rate turn. Input the new altitude. Press FLC (Flight Level Change). You previously determined your climb rate so use the Nose UP/DN button to set your climb speed on the speed tape of the PFD. You have now instructed the FD to fly as you intended or the controller instructed. Sync the airplane bar (V) with the FD Command Bar and you will be making a standard rate turn and begin climbing at the desired air speed.
(A side note: FLC (Flight Level Change) allows you to hold a constant speed in a climb or descent. IE., your climb rate will vary. The other alternative is VS (Vertical Speed). This is ideal for descents. VS sets a specific climb rate and allows speed to vary.)
In all the phases thus far, all you have done is used the FD as a backup to confirm what you intend to do while hand flying the airplane. This backup is passive guidance. You are in command and hand flying the airplane. Should you choose – ignore the FD. Nothing happens!
This is working pretty well. You have now climbed to your requested/assigned altitude, set the engine for desired performance and are now continuing to hand fly via heading and altitude. This is a good time to trim the airplane to marginalize deviations on heading and attitude. Ah, things are going well.
Iit’s time to do some ded(uctive) reckoning as you always want to be thinking/planning ahead of the airplane. You do want to insure that your expected route from pre-flight planning matches with what is actually happening. You pull out your maps, continue to ‘fly outside’ the cockpit, making the occasional but brief check of your avionics to make sure you and the FD Command Bar are in sync. This quick check should include your core engine readings.
You can see where this is going don’t you? Your workload is increasing. At some point, wouldn’t it be convenient if you had a co-pilot fully under your command assist you? The last button on the GFC 700. Press the AP (Auto Pilot) button and let “George” (your new co-pilot) manage airplane trim for you.
All this time, you have been flying without inputting a flight plan!!! Until you pressed AP, you were hand flying. Are you starting to appreciate some of the benefits of the Flight Director?
Here are some more benefits. Use the flight direction as a guide and it will allow you to increase your hand flying skills exponentially as it helps you learn to make small, smooth adjustments in shorter time periods. Your heading hold skill sharpens up. More importantly, your attitude and altitude control really improves. The basic 100’ +/- assigned altitude becomes 10’.
Following the Command Bar in turns and using the GA feature for take off introduces some small but important techniques you will find handy when you pursue your instrument certification.
A pilot should use all the tools on offer. Each piece of avionics available is designed to assist you. Why not (learn to) use them all?