Recent Cross Country Flight with an Avidyne DFC Autopilot

This blog can also be read at Avidyne Live.

Steve Jacobson, VP of Product Management, and I recently took a trip to an avionics shop in PA for an Aviydne DFC autopilot evaluation.  We wanted to get their feedback on the installation time estimates and processes we have put together and to learn more about the hurdles we may encounter as we upgrade Entegra aircraft to the new line of DFC autopilots.

The main concern we have for installing the DFC autopilot is that the rigging and the servos are within the published specifications.  If they are, the DFC autopilot will be a significant improvement over the current rate-based autopilot.  If the rigging and the servos are out of spec then the performance could be degraded and additional troubleshooting will be required to get the advertised performance from the DFC autopilot.  We are working to create simple tests to see if the airplanes are within the published tolerances before we start the upgrade process.  Our plan is to gather data from a few high volume service centers so we can get a sense of the distribution of aircraft that are in and out of spec.  We are also planning to do a small production run after the certification of the autopilot to manage any entry to service problems that may arise and then go forward with full rate production.  It is very important to us that we have a smooth installation with our new line of digital autopilots.

Since we had a 1.5 hour flight each way I used the opportunity to get in some flying time.  It was a beautiful day for flying and we were VFR all the way.  Steve was the PIC and handled the aircraft in the terminal areas.  Once we were in cruise I turned off the autopilot and worked on flying the course, maintaining altitude and handling the radios since we had flight following.  It was good practice for me since I am about a month into my IFR training and the focus to date has been basic instrument flying while handling multiple tasks.  I don’t have a lot of hours in a Cirrus so it was fun to get a feel for the airplane and work on dividing my attention between the various distractions.  I did gain a new appreciation for the left handed Cirrus pilots out there as I was in the right seat and found it challenging to copy down instructions from ATC while hand flying the airplane.

One new advantage I personally discovered with the DFC autopilot is the quality of the flight director.  Since we have the ability to easily swap the autopilots we flew one leg with the 55x and one leg with the DFC autopilot.  I only have limited experience with using a flight director and Steve challenged me to fly it with both autopilots.  On the leg with the 55x the flight director was very challenging and I felt that it increased my workload.  This is due to the inherent technology of a rate based system which causes the command bars to jitter and move constantly even when we were flying straight and level.  I felt that it was much easier to fly using a traditional scan technique.  When we flew the leg with the DFC digital autopilot and engaged the flight director I flew the airplane much better compared to the traditional scan technique.  The command bars were steady and easy to “capture” the correct attitude to fly the GPS course and maintain the correct altitude.  We used it to fly our descent and I was a much smoother pilot because of the flight director.

We have spent a lot of time explaining the new features and functionality of our new DFC digital autopilots.  This is warranted given the breakthrough nature of Envelope Protection and the Straight & Level button, coupled with the straightforward upgrade process.  While the flight director is a feature that currently exists in most of the Cirrus configurations, I personally think this may become a favorite feature of our DFC customers.