Figure 3-2.--Throttle and pitch control block diagram.
ECSS throttle and pitch control is available at the
flashing ITC indicator. This will cause the indicator
PLCC, PACC, and SCC. Manual throttle and pitch
to illuminate steadily.
control is available at the PLCC and PACC.
Automatic or integrated throttle and pitch control
2. Moving the ITC lever to the new indicated
(ITC) is available at the PACC and SCC. The PACC
command. This will silence the bell and cause the
ITC levers, one for each shaft, allow single-lever
indicator to illuminate steadily.
automatic scheduled control of throttle and pitch.
Figure 3-2 shows an overall control block diagram of
DIGITIZED ORDERS.-- The digitized EOT
the throttle and pitch control system.
provides for communication of nonstandard orders for
pitch and rpm. A nonstandard order is a command for
We have briefly mentioned the plant mode control
a specified pitch or rpm that is outside the
system earlier in this chapter. We will now tell you
predetermined settings. If the PACC has throttle
how it works.
control, the operator can set the thumbwheel
switches to make the SET and ORDERED digital
Plant Mode Control System
indicators agree. The operator then moves the ITC to
the ordered position.
The plant mode control electronics is located in the
PACC. This control works with the start/stop logic at
PLANT MODE ORDERS.-- The plant mode
the PACC. As we mentioned earlier, the auto initiate
EOT consists of three possible orders: secure, split
mode is a part of the plant mode control logics. In
plant, and full power. When the plant mode is
plant mode control, the operator can start up or shut
activated, the signal is sent to the PACC. The signal
down the main engines in both engine rooms without
causes the indicator for the given order to flash and
using the individual GTE start/stop controls. The
the bell to sound. The operator acknowledges the
plant mode control is normally used only when all of
order by depressing the flashing indicator. When the
the following systems are in AUTO:
new plant condition is achieved, the indicator will
illuminate steadily. Now, let's move from the EOTs to
1. GTE start/stop control
the throttle and pitch control system.
2. Throttle
Throttle and Pitch Control System
3. Brake
The throttle and pitch control system provides
control of shaft speed and propeller pitch. This is an
4. Air
analog control system that uses continuously variable
signals to control shaft speed and propeller pitch.
