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Avidyne DFC-90 Auto Pilot

Garmin GTN 750 Nav/Com/GPS

Avidyne's DFC-90 Auto Pilot




  • Overview
  • Envelope Protection and Alerting
  • Image
  • DFC-90 Video

DFC90 Attitude-Based Digital Autopilot for Avidyne PFD or Aspen EFD-equipped aircraft

DFC90 for Cirrus, Cessna 182, Beech Bonanza & Baron

Cirrus owners with Aspen
Cirrus owners with Avidyne
Piper owners with Avidyne
Cessna owners with Aspen and 6 pack

 Avidyne’s DFC90 Attitude-Based Digital Autopilot enhances precision of flight and improves safety for your aircraft.

DFC90 and Aspen EFD

DFC90 will utilize either an Entegra EXP5000 or Aspen EFD1000 Pro PFD as the attitude source.

The DFC90 adds the precision of an attitude-based flight control system and Avidyne’s innovative, safety-enhancing EP™ capability.

The DFC90 has all the standard vertical and lateral modes of operation of a turbine-class autopilot system, including Flight Director (FD), Altitude Hold (ALT), Airspeed Hold (IAS), Vertical Speed Hold (VS), Heading (HDG), and Navigation (NAV, APPR, LOC/GS, GPSS).

Customers upgrading from the STEC 55X will notice several major performance and feature improvements including: 

  1. Attitude-Based - Greatly improved stability due to the use of attitude data to control the autopilot inner control loops. This is particularly evident and important when tracking an ILS to minimums in windy conditions.

  2. EP™ - Avidyne’s Envelope Protection. Prevents autopilot-induced stalls and overspeeds—which have previously been a major contributing factor in GA accidents—when the autopilot is engaged. EP also provides visual and aural warnings to the pilot.  

  3. EA™ - Avidyne’s Envelope Alerting. Available lift and speed margins are calculated constantly in the background, providing visual and aural warnings to the pilot when the aircraft is nearing its normal flight parameters, even when the autopilot is off.  

  4. “Straight & Level” Button – Recovers the aircraft from unusual attitudes. Overrides all autopilot modes and levels the aircraft in both pitch and roll from a wide range of capture attitudes for an added measure of safety.  S&L button provides added peace of mind—especially for non-pilot in right seat (i.e. Cirrus Parachute).

  5. Indicated Airspeed Hold (IAS)  - New vertical mode includes a dedicated Airspeed knob and a new airspeed bug on the PFD. Provides constant speed flight level changes.

  6. Enhanced Fight Director capability of the DFC90 is vastly improved and greatly improves the ability to hand-fly approaches. 

  7. Synchronized Heading Bug – With the DFC90, turns are commanded in correlation with the spin of the heading knob. In other words, you can make the autopilot do a right-hand 270 degree turn if you spin the heading knob right 270 deg. 
Entegra with DFC90 Autopilot

There are many other improvements, such as a dedicated Vertical Speed knob, pitch hold mode, wide autopilot engagement, additional annunciations in PFD 8.0, a dedicated GPSS button, automatic Back Course Approach selection, multiple color annunciations to indicate armed and active states, intercept mode annunciations, and Avidyne’s hallmark ease of use.


DFC90 Expansion

Plug & Play for Beech Baron, Bonanza and Cessna 182 Owners.

Cessna C182 featuring Avidyne DFC90
C182 with DFC90 and Aspen Pro PFD.

 Extending certification basis to include the Beech Baron & Bonanza and Cessna 182 aircraft.

  • For compatible autopilots, DFC90 will utilize existing servos, brackets, wiring and trays (for the STEC 55x) to minimize installation cost & time.
  • The ‘Straight & Level’ and Flight EP safety features will now be available to a large group of aircraft owners.
  • List price of DFC90 is $9,995 for piston single aircraft, and $14,995 for twins and turbine aircraft. Available starting in 2012. (Contact Premier Avionics for current pricing.)


• Width: 6.25" (159mm)
• Height: 1.5" (38mm) 
• Depth: 10.6" (279mm)


• 2.02 lbs (0.92 kg)

Go to for more info on the DFC90 Autopilot

More info on DFC90/100 EP™ EA™

The Avidyne DFC90 & DFC100 exceed the functionality of the current and competitive systems in the following ways:

  • The Avidyne DFC90/100 control panel uses backlighting of the function keys to provide feedback regarding the status of the autopilot. Green denotes an active mode and Blue denotes an armed mode. This helps eliminate any confusion regarding the current and armed modes of the autopilot.

  • The ALT mode contains a “baro-inertial” altitude and vertical speed estimator, enabling captures without overshoot, no porpoising, and accurate control even in turns.

  • WAAS and ILS approaches can be executed without “hunting” from even extreme capture angles even under conditions of high crosswind and shear.

  • Straight & Level: When activated, the S&L mode immediately attempts a recovery from arbitrary initial conditions; it’s both an emergency recourse and pilot fallback mode for everyday use. For the greatest possible envelope of success, the mode utilizes maximum control power, with relaxed (expanded) g and rate limits.

  • EP™ (Avidyne's Envelope Protection) is Avidyne's proprietary autopilot software which dynamically controls the flight of the aircraft in order to prevents stalls or overspeed situations that might otherwise be induced by the autopilot or flight director commands. This feature continuously accounts for all sources of lift demand (pitch, bank, altitude, speed, weight), computes safe limits on the flight condition, and constrains the autopilot to fly within these safe limits.

  • EA™ (Avidyne's Envelope Alerting) is Avidyne's proprietary software which dynamically provides the pilot with full time audible and visual alerting in the event that aircraft is flown outside of its safe limits and even when the autopilot and flight director are not actively engaged.


EP (Avidyne's Envelope Protection) is a unique and proprietary Avidyne autopilot feature which prevents the pilot from commanding the autopilot to stall or overspeed the aircraft.

The term “Flight Envelope” normally implies airspeed and altitude but the system is significantly more capable than that. While indicated airspeed limits are met by our EP, neither the aircraft’s safe operating range, nor Avidyne’s autopilot protections, are that simple.

EP monitors and limits the instantaneous lift demand on the aircraft. It is active in both Autopilot Engaged and Flight Director modes. Lift is constrained by saturating pitch rate command to the maximum value that will not exceed the wing g loading such that the sum of kinematic and (projected) gravitational g load remain within 90% of the maximum available. The available lift calculation is sensitive to flaps, speed brakes, weight, temperature, speed, and incorporate margins purposely designed to mitigate ice.

The term “kinematic g” takes into account the turning of the aircraft’s velocity vector. Any attitude whatsoever is automatically mathematically incorporated by this method. Next, gravity is vectorially added to the lift demand to the extent it projects on the wing normal.

Thus, the autopilot knows how much g is needed to maintain level turn or constant climb rate at any attitude, and that g request is “fed forward” into the control loop request before it even can generate a loop error. This means that the lift demand is pre-biased to account for the extra wing loading needed in turns. As an example, at 75 deg bank, the starting point for g request from the pitch inner loop is 3.9g. This is then augmented by any control loop tracking error (the closed loop part of the autopilot) and then limited (if necessary) by EP.

Last, pitch rate is the “lever” by which the EP is implemented. By imagining flight through a zero-g pushover, it is possible to see that EP can arbitrarily constrain lift demand by modulating pitch rate: a steady “push” holds lift to zero. This is exactly how the autopilot works. Besides being “all attitude” capable, this method additionally has the collateral consequence of controlling steady level flight to 1.1Vstall. In turning flight, a higher speed will result, but it’s all implemented naturally through pitch rate. The significant principal benefit is that EP acts with all the bandwidth (speed of response) of the pitch rate control loop, which is the most reactive and capable loop in any autopilot, and limited only by servo performance. Speed or attitude controls (such as used by others) are in comparison relatively ineffectual. This implementation allows EP to respond successfully to all but the most severe initial conditions avoiding stall in almost any circumstance. While override is always at the pilot’s discretion, all modes, including Straight and Level and Flight Director, are envelope protected.

 Full Time EA (Avidyne's Envelope Alerting):

Full Time Envelope Alerting is active even when the DFC90/100 autopilot or flight director modes are not engaged and alerts the pilot to conditions that can lead to stalling or overspeeding the aircraft.

With the AP disengaged, the system is still much more than a flight director. The DFC90/100 Flight Control system encourages safe and effective operations in all modes of flight. The flight director is fully envelope protected, just as is AP-engaged flight, and can be triggered to take into account the aircraft’s reduced capability under icing conditions.

When disconnected, the DFC90/100 autopilot system continues to calculate lift, monitoring speed, pitch, bank and commands for potential envelope exceedances. The Flight Director Command following performance is also tracked, and persistent errors, whether caused by automation or piloting, can trigger helpful alerts. Any hazardous conditions are announced by built-in audio alerting and by external telemetry data (available for display). These are significant benefits to the single pilot whose attention is demanded over long hours, and potentially distracted by many information sources.

The DFC-90 Auto Pilot

Avidyne AMX-240 Audio Panel

Watch the DFC-90 Video to see its benefits and features!