Installation manual

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

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. This AP Cal is not supposed to be

conducted for the DFC90 and is only applicable for STec 55X installs. Performing this

STec 55X Flight Director/Autopilot calibration on a DFC90 installation will result in

improper DFC90 behavior.

There have been a small handful of reports of lateral oscillation after a DFC90

installation in Cirrus aircraft and to date, each report has been traced to “stiction” in the

flight control surfaces or a bad roll-axis servo or a bad aileron interconnect bungee (the

most likely cause) or a mis-bent trim tab. The DFC90 Installation Manual does contain

some tests to determine if this is case in an individual aircraft.

There have also been a handful of reports of pitch porpoising after a DFC90 installation

in Cirrus aircraft. So far, every one of these reports has been traced to an out-of-spec

pitch servo.

Release 2 added the “SERVO LIMIT” message capability to the system which indicates

the roll trim cartridge has been fully compressed and is at it’s limit for some reason.

There are some reports from customers now seeing this message – if you do see, Avidyne

recommends you contact a service center to determine why. Common reasons are

unnecessary pilot input on the flight controls, a bad roll trim cartridge itself, bad aileron-

rudder interconnect bungee, a mis-rigged aircraft trim tab(s).

For non-primary engine (“SIU-equipped) Cirrus aircraft who upgraded/installed PFD Rel

8.0.5 and DFC90 Rel 2, SIL 606-00006-002, dated 26 June 2012 describes a condition

where Underspeed Alerts are not suppressed in the landing phase, potentially resulting in

nuisance alerts. Details, options and intended resolution are provided in the SIL which

can be found at http://www.avidyne.com/support/downloads/index.asp (updated 26 June

2012)

(DFC100) What other kind of installation “gotchas” have you heard about from the

field?

None so far but some customers and installers are initially surprised to learn of the wiring

steps described above on page 3 of these FAQs.