T-34C AIRCRAFT SYSTEMS FAMILIARIZATION
AOA Test Switch
The AOA test switch is located on the TEST panel at the bottom of the instrument panel in both
cockpits. It is labeled AOA, APRCH, and STALL and is used to test the AOA and stall warning
systems. Selecting APRCH causes the indicator and indexer in both cockpits to display 20 units
and a yellow circle (yellow doughnut). The STALL position causes the rudder pedal shakers to
activate immediately and both cockpits to display 29 units and a green ( V ) chevron.
Rudder Pedal Shakers
Rudder pedal shakers, located on each aft rudder pedal, provide both pilots with a physical
warning that the aircraft is approaching a stall. An eccentric metal mass is driven by an electric
motor when activated by the AOA system to cause pedal vibrations in both cockpits when the
aircraft is 5-10 KIAS above stall.