Installation manual

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

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. There may however be some slight noticeable reduction in

precision and crispness in the vertical axis modes when compared to aircraft equipped

with DFC90/100s and a full pitch servo. Depending on the environmental and aircraft

dynamics conditions, this may be observable as a slower reaction time in vertical

turbulence, flap deployment/retraction, IAS mode tracking and unusual attitude

recoveries using the Straight and Level button. It is very important however, that the

bendable pitch trim tab is set in accordance with Cirrus factory specifications as noted in

the DFC Installation Manual. (Note that installations in Bonanzas, Barons and

Skylanes are required to have a functional pitch trim servo due to different aircraft

and servo dynamics than found in Cirrus.) (updated 24 July 2011)

(DFC90, 100) Is it normal for my DFC90/100 control head to be very hot in-flight?

Yes, in some installations this may be normal. For DFC90 installation configurations,

this heat is coming from the Garmin GNS-430 that is directly on top of the DFC90 and is

not generated by the DFC90 itself. The hot temperature is confined to the control head

and is not working its way back to the autopilot processor board and its components. If

you find your DFC90 control head to be unusually hot, try turning off the 430 #2 to

validate it as the source of the heat. Avidyne understands that some Cirrus aircraft were

shipped from the factory with a cooling fan behind the radio stack and that there is also

an aftermarket installation available to do the same. Installation of that fan is left up to

the individual owner – Avidyne believes the heat is not going to cause any problems or

shortened lifespan of the autopilot. For DFC100 systems, this should not be an issue

since the Garmin 430s are replaced by the FMS keyboard which produces only negligible

heat and does not heat up the DFC100 control head.

(DFC90, 100) What other kind of operational “gotchas” have you heard about from

the field? The most common tip to keep in mind is that following a night flight, ensure

the instrument lighting rheostat is not in the night position. If left in the night position,

the lights on the DFC90/100 control head will appear to be “inop”. They are not inop,

they’ve just been dimmed to a point that they appear off in daylight conditions. A simple

twist of the bolster rheostat will solve that issue.

For DFC100 systems with Release 1 software, it is common for the Underspeed aural

alerts to be issued during roll out after landing and taxi back. This issue should be largely

resolved with the fielding of DFC100 Release 2 and IFD 9.2.4. (updated 10 Oct 2011).

(DFC90, 100) I used to “help” my old autopilot during some flight maneuvers (e.g.

intercepts to final, stabilize ILS, etc) where it had difficulty. Will that be necessary with

the DFC90 or DFC100 too? No! In fact, any pilot input on the yoke or rudder (other

than minor rudder input to maintain coordinated flight), will likely adversely affect the

performance of the DFC series of autopilots. It is highly recommended, that pilot input