THROTTLE CONTROL - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General

Throttle Control Mechanical Parts ** ON A/C NOT FOR ALL

The throttle control system consist of:

the throttle control lever,
the throttle control artificial-feel-unit,
the throttle control unit,
the electrical harness.

In addition each throttle control lever is fitted with an instinctive pushbutton switch.
This pushbutton switch serves for the de-activation and disengagement of the autothrust function.
The design of the throttle control is based upon a fixed throttle concept: this means that the throttle control levers are not servo motorized.

** ON A/C NOT FOR ALL

2. Throttle Control Mechanical Parts

A. Throttle Control Lever

Acquisition of the Throttle Control Discrete-Signal by the FADEC ** ON A/C NOT FOR ALL

Throttle Control System ** ON A/C NOT FOR ALL

The throttle control handle comprises:

a throttle control lever which incorporates stop devices and the autothrust instinctive-disconnect pushbutton-switch,
a graduated fixed sector,
a reverse latching lever.

The throttle control lever moves over a range from:

minus 20 degrees TLA (Reverser Full Throttle stop) to 45 degrees TLA (Forward Full Throttle stop).

An intermediate mechanical stop is fitted at 0 degree TLA.
This stop is overriden when the reverse latching lever is pulled up for selection of the reverse power.
This idle stop is reset as soon as the lever is selected back to forward thrust area.
In the forward thrust area, there are two detent points:

MAX CLIMB detent point set at 25 degrees TLA,
MAX CONTINUOUS/FLEX TAKE OFF detent point set at 35 degrees TLA.

In the reverse thrust throttle range, there is one detent point:

minus 6 degrees TLA, this position corresponds to the selection of the thrust reverser command and the Reverse Idle setting.

From minus 20 degrees TLA to 0 degree TLA, the autothrust function cannot be activated.
In the middle throttle range (0 degree to 35 degrees TLA), the autothrust function can be active if engaged.
This range corresponds to the selection of MAX CLIMB or MAX CONTINUOUS thrust limit mode (except the FLEX TAKE OFF mode).
If the autothrust is not engaged, the engine control is manual.
In the forward range (35 degrees to 45 degrees TLA), the autothrust function cannot be activated (except in alpha floor condition).
This range corresponds to the selection of FLEX TAKE OFF/MAX TAKE OFF (GO AROUND) mode.
The throttle control lever is linked to a mechanical rod. This rod drives the input lever of the throttle control artificial-feel-unit.

B. Throttle Control Artificial-Feel-Unit

Throttle Control Artificial-Feel-Unit ** ON A/C NOT FOR ALL

The Throttle control artificial-feel-unit is located below the cockpit center pedestal. This artificial feel unit is connected to engine 1(2) throttle control lever and to the engine 1(2) throttle control unit by means of rods. The artificial feel unit is a friction system which provides a load feedback to the throttle control lever.
This artificial feel unit comprises two symmetrical casings, one left and one right. Each casing contains an identical and independent mechanism.
Each mechanism is composed of:

a friction brake assembly,
a gear assembly,
a lever assembly,
a bellcrank assembly,
The throttle control lever travel is transmitted to the artificial feel unit and to the throttle control unit.
The linear movement of the throttle control levers is transformed into a rotary movement at the bellcrank which turns about the friction brake assembly shaft. This movement rotates a toothed quadrant integral with the shaft.
This toothed quadrant causes inverse rotation of a gear equipped with a disk which has four detent notches. Each notch corresponds to a throttle control lever setting and is felt as a friction point at the throttle control levers.

C. Throttle Control Unit

Throttle-Lever-Angle Harness ** ON A/C NOT FOR ALL

Control Unit - Mechanical Part ** ON A/C NOT FOR ALL

Thrust Control Power-Supplies ** ON A/C NOT FOR ALL

A mechanical rod transmits the movement of the throttle control lever.
It connects the throttle control artificial-feel-unit to the input lever of the throttle control unit.
The throttle control unit comprises:

an input lever,
mechanical stops which limit the angular range,
2 resolvers, the signals of which are dedicated to the Electronic Control Unit (ECU) (one resolver per channel of the ECU),
6 potentiometers fitted three by three. Their signals are used by the flight control system,
a device which drives the resolver and the potentiometer,
a pin device for rigging the resolvers and potentiometers,
a safety device which leads the resolvers outside the normal operating range in case of failure of the driving device,
two output electrical connectors.

The input lever drives two gear sectors assembled face to face. Each sector drives itself a set of one resolver and three potentiometers.
The relationship between the throttle lever angle and Throttle Resolver Angle (TRA) is linear and 1 degree TLA = 1.9 TRA.
The accuracy of the throttle control unit (error between the input lever position and the resolver angle) is plus or minus 50 minutes TRA (includes all aircraft mechanical and electrical errors up to the resolvers outputs). This does not include any possible aircraft wiring effect on the ECU or ECU internal processing.
The maximum discrepancy between the signals generated by the two resolvers is 0.25 degree TRA. The TLA resolver operates over two quadrants: the first quadrant serves for positive angles and the fourth quadrant for negative angles.
Each resolver is dedicated to one channel of the ECU and receives its electrical excitation from the ECU.
The ECU considers a throttle resolver angle value:

less than minus 47.5 degrees TRA or,
greater than 98.8 degrees TRA,
as resolver position signal failure.

The ECU incorporates a resolver fault accomodation logic. This logic allows engine operation after a failure or a complete loss of the throttle resolver position signal.

[Rev.10 from 2021] 2026.04.01 13:06:19 UTC