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Avidyne | DFC90, 100 FAQs (Last updated: 26 June 2012)

DFC90 and DFC100 FAQs

Updated 26 June 2012

General Questions

(DFC90, 100) What are the main differences between the DFC90 and DFC100?

There are two functional differences between and the autopilots and two architectural

differences. Functionally, the DFC100 supports the R9 Vectors mode and it adds a

VNAV capability. Architecturally, the DFC90 autopilot takes its input from the Avidyne

or Aspen PFD and the Garmin 430s (or GPS/Nav/Coms connected to the Aspen PFD)

while the DFC100 is driven by the IFD and the Avidyne FMS 400/900w system, and the

DFC100 system communicates to the rest of the R9 system via the Byteflight digital

databus while the DFC90 does not. (updated 17 April 2012)

(DFC90, 100) What are the main features of these autopilots? First and foremost,

since it is taking advantage of the on-board PFD digital ADAHRS, they are able to

provide a much more precise operation (e.g. no overshoots, no wandering, no divergent

behavior inside the FAF, etc). Secondly, they add some very specific safety features such

as Straight and Level and Envelope Protection. Thirdly, they add new modes such as

IAS (Indicated Air Speed) mode. Finally, the Flight Director becomes much easier to use

and follow.

(DFC90, 100) How does IAS mode work? Just like VS mode, IAS mode can be used to

follow a commanded indicated airspeed as set by a new IAS bug or it can be used to

perform an altitude capture at a specified airspeed. Once set via the IAS bug and

engaged, the autopilot will adjust the aircraft flight path angle as required to track the

commanded IAS. The system will not “descend to climb” or “climb to descend”. In

other words, if you were currently flying at 120 KIAS and commanded a 1000’ climb at

140 KIAS, the aircraft will not first descend to pick up airspeed before climbing to the

new altitude target. Likewise, if you were currently flying at 120 KIAS and commanded

a 1000’ descent at 90 KIAS, the aircraft will not first climb to bleed off airspeed before

descending to the new altitude target at 90 KIAS. In both cases, since the autopilot

determines that it cannot comply with the contradictory input requests, it was hold current

state until the pilot takes an action such as a power change or a target speed change.

(DFC90, 100) Why did you retain some of the same user interface as the S-TEC? This

was purposely done to minimize the amount of re-training required for the S-TEC user

community since that represented the vast majority of our early customers. Habit

patterns are a powerful force and we wanted to leave that as intact as feasible. (updated

24 July 2011)

(DFC90, 100) Where can I learn more about the “button-ology” of the DFC

autopilots? These are fully addressed in the autopilot user’s manuals. The link for the

DFC90 Pilot Guide is here and the link for the DFC100 Pilot Guide is here.

Summary of content (17 pages)

PAGE 1
DFC90 and DFC100 FAQs Updated 26 June 2012 General Questions (DFC90, 100) What are the main differences between the DFC90 and DFC100? There are two functional differences between and the autopilots and two architectural differences. Functionally, the DFC100 supports the R9 Vectors mode and it adds a VNAV capability.
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(DFC90, 100) Do I still need to use the AP and FD buttons on the instrument panel? No, those buttons become non-functional in DFC90 and DFC100 integrations. In fact, as part of the installation for those aircraft that had them, those buttons are removed and replaced by a cover plate. Your installer has the option of either ordering a cover plate from Avidyne as part of the initial order (for black or beige Cirrus instrument panels) or building their own cover plate.
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• • • • • • Added an alert to notify the pilot if the POH bank angle limit has been exceeded. This comes in the form of an aural alert (“Caution, Excessive Bank”) and a text alert (“BANK LIMIT”); Provides suppression of Underspeed alerting while on short final, in the flare, and during landing rollout.
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• • • • • • • • • Adds support for the Entegra PFD equipped PA46 Matrix and Mirage aircraft; Changed system behavior such that in single AHRS equipped aircraft, if an AHRS-Turn Coordinator Miscompare is observed in-flight, the autopilot will no longer disconnect.
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(DFC90, 100) Are there any other sources of information where I can learn more about the autopilot products or programs? Avidyne is hosting frequent webinars now on the DFC series of autopilots. Our products page of our website also contains some more information at http://avidyne.com/products/dfc90/index.asp and http://avidyne.com/products/dfc100/index.asp . We also maintain an online forum where more information gets periodically added. This can be accessed at http://avidynelive.com/forum_topics.
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• • • • • • • Remove all the legacy gear, if not already done so by the Aspen mod (e.g. ADI, HSI, Remote Annunciators, Mode controllers, DGs, Alt/VS Preselectors, etc); Replace the autopilot tray (except for S-TEC 55/55X installations where the tray is reusable); Install the new equipment (e.g.
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the same form factor in an effort to minimize costs and installation difficulties. (updated 26 June 2012) (DFC100) What do you expect the DFC100 install time to be in Cirrus aircraft? Avidyne is estimating 8-12 labor hours for installers to perform the complete install and checkout for Cirrus aircraft.
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(DFC90, 100) Are there any autopilot calibrations required? No, there are no autopilot calibrations required after installation. This is part of the “digital dividend”. (DFC90, 100) Should I still put in a roll servo in my Cirrus? We understand that a sizeable number of potential Cirrus DFC90 customers have performed the roll servo mod and as of DFC90 Release 2, we have added support for that configuration. For the DFC100, the roll servo has always been supported.
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Also, some installers are finding that the rubber gasket in some existing S-Tec 55X trays prevents, or makes challenging, a solid connection at the pins. The Avidyne STC was modified to allow installer removal of the rubber gasket should it be present and causing a connection problem. There have also been a few examples of installers performing an autopilot calibration (AP Cal) following installation of the DFC90.
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Failure Mode Questions (DFC90) Will the DFC90 work after a loss of air data? Yes, modes such as Straight and Level and Pitch Roll still work without air data. The system can still track an ILS without air data as well. (DFC90) Will the DFC90 work after a loss of AHRS (attitude) data? No, the DFC90 will not work without AHRS input.
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This is accessible through the Avidyne Live forum at http://avidynelive.com/forum_posts.asp . (DFC90, 100) How can I be sure my aircraft will see better performance with a DFC autopilot? You will. A digital autopilot is really just a bunch of equations but not all equations are created equal and ours are better. We have an altitude estimator, gain scheduling, cross feeds, feed forward, lift calculations and range-to-go estimations. The results are better flight.
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(DFC100) Can you explain more about the Underspeed protection that comes with Envelope Protection (EP) in the DFC100? Like the DFC90, Underspeed protection is designed to prevent autopilot-induced stall conditions. If, between a combination of power settings or commanded climb conditions result in a decaying airspeed to be approximately 1.
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airplane, you are overpowering the spring cartridges and flexing them a lot more than their typically undeflected state when under autopilot control. (DFC90, 100) Will the DFC autopilot work well in a Cirrus aircraft that does not have a pitch servo (only has pitch trim servo)? Yes. One of the test aircraft used in development is a pitch trim only SR20 and we have found the performance to be on-par with full-servo’d aircraft.
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on the flight controls during coupled (AP) operations be avoided. For DFC90 (Release 2 or later) or DFC100 configurations (all versions), a “SERVO LIMIT” text message will be displayed on the PFD page if the mechanical limit switch has been tripped in the roll trim motor. If you see this message, know that lateral tracking accuracy will likely be impaired until the input condition generating this message has been removed (e.g. pilot stops making a “helping” control input).
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(DFC90) What does a typical DFC90 installation in an Aspen-equipped Cirrus involve? The upgrade to the DFC90 is a two-part upgrade – the Aspen PFD must be updated in order to communicate with the DFC90 . The second part of the DFC90 upgrade is to replace the STec flight control computer with the Avidyne DFC90 flight control computer. This is just a matter of having the autopilot flight control computers swapped and some flap wiring added.
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(DFC90) Will the DFC90 be certified for other aircraft? If so, what and when? Yes, the table below summarizes the configurations currently announced: Aircraft Type Cirrus SR22, 20, SRV Piper PA46-350 Piper PA32 Cirrus SR22, 20 Bonanza 33, 35, 36 Baron 55, 58 Skylane 182 PFD Supported Avidyne Avidyne Avidyne Aspen Aspen Aspen Aspen Availability Date Now Now Q3 2012 (est) Q3 2012 (est) Q3 2012 (est) Q3 2012 (est) Q3 2012 (est) If you are interested in a specific make/model of aircraft not on the list above
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(DFC90) Will the DFC90 work with Cirrus SRV aircraft (those with S-TEC 55SR)? Yes it will. The upgrade of a 55SR to a DFC90 results in the full-featured DFC90 system, no missing or degraded elements. (DFC90, 100) How do I get upgrades to the DFC autopilot if they come out? The DFC series of autopilots will have what is called a Field Loadable Software capability.