Installation manual

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

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. This will come down to a personal tradeoff – would

you rather have much higher performance and a safer system all the time, or a poorer

performing autopilot that has some form of “limp home” capability? This is much less a

factor in DFC100 systems since it uses a dual IFD input in the Platinum configuration.

(DFC90) Will the DFC90 work after a loss of the PFD display? Yes, in the event the

display is non-functional, the autopilot is still functional. Remember that the PFD

display is the location to set and see target values such as IAS, and VS targets, however,

by pressing on the ACP knobs, the bugs are sync’d to the current aircraft state and then

by counting knob clicks, new targets can be accurately set. The user’s manual has more

extensive guidance in these kinds of scenarios.

Training Questions

(DFC90, 100) What kind of training materials exist now or will exist for the DFC

series of autopilots? The User's manual for the DFC90 Autopilot is available now and

can be downloaded via this site: http://www.avidyne.com/publications/dfc90/600-00252-

000.pdf Another location for the download is

http://www.avidyne.com/landing/dfc90/index.asp

The User’s manual for the DFC100 Autpilot is available now and can be downloaded via

this site: http://www.avidyne.com/publications/dfc100/600-00270-000.pdf

Our goal is that the end-user training is complete in the same few hours that the airplane

is down for the installation.

Finally, there are some 3

party individuals and groups who are generating various

training material and when that is available, we will notify the customer community.

Performance Questions

(DFC90, 100) How does the DFC autopilot achieve a “ride on rails” performance level

using the existing S-TEC servo and trim cartridges? In the pitch axis, we are

commanding both the pitch servo AND the pitch trim servo all the time. We call it a

trimmervator. Because of slop and spring detent, the two servos sometimes compete for

control of the aircraft, so giving them synchronized inputs ensures the elevator will do the

right thing either way. Meanwhile, differential commands create trim. In roll, the spring

cartridge is not dynamically involved, and the principal difficulty is the high servo

starting voltage, which is compensated for in software. Also you may wish to refer to our

engineer's blog post on servo system details if you're interested in more information.