There are two
pairs of rudder pedals: one each for the commander and pilot. The
commander's and pilot's rudder pedals are mechanically linked so
that movement on one side moves the other side. When a pedal is
depressed, it moves a mechanical input arm in a rudder pedal transducer
assembly. Each RPTA contains three transducers-channels 1, 2 and
3-and generates an electrical signal proportional to the rudder
pedal deflection. An artificial feel is provided in the rudder pedal
pedals command orbiter rotation about the yaw axis by positioning
the rudder during atmospheric flight. In atmospheric flight, flight
control software performs automatic turn coordination; thus the
rudder pedals are not used until the wings are level before touchdown.
The RPTA SOP
converts the selected left and right commands from volts to degrees;
selects the largest of the left and right commands for output to
flight control software after applying a dead band; and if redundancy
management declares an RPTA bad, sets that RPTA to zero.
pedals can be adjusted 3.25 inches forward or aft from the neutral
position in 0.81-inch increments (nine positions). The breakout
force is 10 pounds. A pedal force of 70 pounds is required to depress
a pedal to its maximum forward or aft position.
pedals provide two additional functions unrelated to software after
touchdown. Rudder pedal deflections provide nose wheel steering,
and depressing the upper portion of the pedals by applying toe pressure
provides braking. Differential braking may be used for nose wheel
RPTA is powered when the flt cntlr on/off switch on panel F7 is
positioned to on . The pilot's RPTA is powered when the flt cntlr
on/off switch on panel F8 is positioned to on .
The RPTA contractor
is Honeywell Inc., Clearwater, Fla.