POWER PLANT
18-20
For Training Purposes Only
May 03
P I L O T T R A I N I N G G U I D E
Thrust Levers
Description
The thrust lever quadrant contains the thrust levers, thrust reverse levers, micro-
switches and internal locks and stops necessary to control the engines in forward and
reverse thrust.
Operation
Thrust Levers
Most functions of the thrust levers are conventional in operation. Thrust lever quadrant
settings are SHUTOFF, IDLE, and MAX POWER.
Mechanical Stop
A mechanical stop prevents the thrust levers from inadvertent movement. When the
thrust lever is at SHUTOFF, the thrust lever is mechanically locked in that position.
When the thrust lever is at idle, the mechanical stop prevents the thrust lever from
being accidentally moved to SHUTOFF. The mechanical stop is released by lifting the
idle/shutoff release latch on the thrust lever.
Friction Knobs
A friction knob allows the pilot to change the friction setting for the thrust levers.
Thrust Lever Position Measurement
Actual thrust lever positions are electrically measured by rotary variable differential
transformers (RVDTs) or sensed by microswitches that are housed within the thrust
lever quadrant. The information is provided to the N
1
control amplifier, the flight
control computers (FCCs), and the data concentrator units (DCUs). Other aircraft
systems receive thrust lever position information, including:
•
landing gear warning system
•
takeoff configuration warning system
•
cabin pressurization
•
ground spoilers
Takeoff/Go-Around (TOGA) Switches
A takeoff/go-around switch is mounted on each thrust lever. When pressed, the TOGA
switch signals the flight control computers to activate flight director modes
accordingly.
