Page 7-9
Pilot’s Operating Manual
Revision A2: Nov, 2004
Sub-section 7
STALL WARNING/IDENTIFICATION
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
FLAP ASYMMETRY
If asymmetry between the left and right flap positions exists for more than 2 seconds, then the FLAP
annunciator (Pilot’s group only) will illuminate.
WEIGHT-ON-WHEELS ASYMMETRY
If asymmetry between the positions of the left and right weight-on-wheels relays exists for more than 4
seconds, then a SQUAT annunciator (Copilot’s group only) will illuminate.
SSU SELF TEST
A built-in test within the SSU detects the following faults:
• Loss of 26 VDC supply
• Loss of internal power or short circuit
• Loss of airflow angle sensor excitation
• Loss of flap position input
• Airflow angle sensor transformer winding open or short circuit
If any of the above occur, an external relay causes a SSU annunciator to illuminate. If the weight-on-
wheels switch is in the flight condition, a magnetic indicator associated with the faulty SSU will display
white. The magnetic indicators are located on the stall identification diagnostic panel.
