Dual Digital AoA / Stall Warning Systems
The Dual Stall Warning Computer contains two independent stall warning computer modules in a common enclosure. Each module receives inputs from its respective on-side sources and combines these signals to provide stall warning signals. The stall warning signals are used to drive control shaker motors and stall warning annunciators, as well as analog and digital indicators. Each of the modules consists of a microcontroller-based unit with appropriate interface circuitry.
The basic stall warning signal is derived from the Angle of Attack (AoA) signal supplied by the aircraft Angle of Attack transmitter and modified by flap configuration, air speed, and altitude.
Before use, the Angle of Attack input signal is checked for integrity and for vane movement, and the flaps input is checked for proper coding. When the aircraft is on the ground, a pilot activated test that includes shaker operation may be performed.
Each computer module provides a buffered analog output for a display of Normalized Angle of Attack. The Normalized Angle of Attack function is the ratio of actual Angle of Attack to the stall Angle of Attack.
Each module also provides a buffered ARINC 429 low speed digital output containing local Angle of Attack, Normalized Angle of Attack, vane Angle of Attack, discrete settings, Angle of Attack rate, and other data.
To permit access to pertinent maintenance data, each module is provided with a test connector for interface with a PC-based test set.
The Dual Stall Warning Computer has been qualified to the environmental requirements of RTCA/DO-160C typical for turbojet composite aircraft. The software has been qualified to the RTCA/DO-178A Essential Level. The system in which this computer is used has obtained FAA TSO C54 approval.
For more information regarding Safe Flight’s various Angle of Attack applications, click on a link below.