Digital Autopilot for Twin Otter Aircraft

Digital autopilot for Twin Otter aircraft is here. After several months working with Genesys (S-TEC) to gain approval for a new digital three axis autopilot, final flight testing was completed last month in Calgary, using one of Rocky Mountain Aircraft‘s Twin Otters.

The new system was put through its paces in all modes and aircraft configurations and performed flawlessly throughout the flight testing.

STEC 3100
STEC 3100 Installation

The FAA issued the STC SA09761DS on October 06, 2020.

With a list price of just under $25,000 for a full three axis autopilot, the 3100 is cheaper that the two axis limited functionality System 65 autopilot it replaces.

All the components are on condition only, eliminating the costly and time-consuming overhaul of servos that blighted the OEM Collins autopilots installation.

Digital-Flight-Control-System-DFCS
Genesys S-TEC 3100 Digital Flight Control System

The Details

The System is a digital three-axis attitude-based Digital Flight Control System (DFCS), and is designed for installation in aircraft equipped with a dual or single Air Data and Attitude Heading Reference System (ADAHRS), and/or DFCS computer internal sensors.

The System provides roll, pitch and (Optional) yaw modes along with an integral autotrim feature. The autopilot  includes a straight and level recovery feature, as well as envelope protection/alerting features.

The Programmer/Computer provides a means to engage the autopilot, select modes of system operation and to annunciate system modes and status. The Programmer/Computer consists of two sections: roll and pitch. The roll section accepts steering inputs from the navigation radios and the ADAHRS or internal sensors and uses this information to drive the Roll Servo. The pitch section receives signal inputs from the Primary Flight Displays and ADAHRS or internal sensors, and uses this information to drive the Pitch Servo. Yaw axis stabilization is provided by drive commands to a remote mounted Yaw Servo.

The Elevator Trim is automatically controlled by the Trim Servo, which also provides trim annunciation.