Specifications

SECTION III
INSTRUMENTATION AND AVIONICS
MODEL 560
A built-in power up test system (PBIT) will automatically detect any failure of the display at power up or
during continuous (CBIT) operation. If the pilot desires to test the system after it is powered up, pressing
and holding the APR button while pressing the ATT button twice within two seconds will start an initiated
built-in test (IBIT). The IBIT mode cannot be accessed at airspeeds greater than 40 knots. The APR
button must be held in to cycle through all the IBIT displays.. If a failure is detected, the appropriate part of
the display is replaced with a message indicating the failure. Where it is not possible to display an
appropriate message (such as processor failure), the display backlight is switched off.
ANGLE-OF-ATTACK AND STALL WARNING SYSTEM
The angle-of-attack system is powered by 28 volts direct current (DC) from the left main DC bus
through a circuit breaker on the left circuit breaker panel and incorporates an angle-of-airflow sensor, a
signal summing unit, a vane heater monitor, an angle-of-attack indicator, an approach indexer and a stick
shaker on the left control column. The vane type angle-of-airflow sensor, which is located on the forward
right side of the fuselage, detects the angle of airflow and deflects accordingly. The wedge-shaped vane
streamlines with the relative airflow and causes a transducer, at which it is mounted, to send signals to the
signal summing unit (computer) located under the floor of the aft cabin baggage compartment. Signal
inputs concerning flap position are also received by the signal summing unit. It then compensates for that
variable and transmits the information to the angle-of-attack indicator and the optional indexer. Indications
are accurate throughout the weight and CG range of the airplane.
The full range type indicator is calibrated from 0.1 to 1.0., and marked with red, yellow and white arcs.
Lift information is displayed on the indicator with 0.1 representing near zero lift and 1.0 representing stall.
Lift being produced is displayed as a percentage and, with flap position information, is valid for all airplane
configurations and weights. At 1.0 where full stall occurs, 100 percent of the available lift coefficient is
being achieved. At the bottom of the scale (0.1) near zero lift is being produced.
Figure 3-6 Standby Flight Display
I 3-14 Configuration AA 56OMB-01