Last Updated on 4 years by teboo
022 09 01 00 Autothrust system
022 09 01 01 Purpose, operation, overcompensation, speed control
Syllabus reference BK Syllabus details and associated Learning Objectives
(01) Describe the purpose of the autothrust system and explain how the FMAs will be the only indication on active autothrust modes.
(02) “Explain the operation of an autothrust system with regard to the following modes:
— take-off/go-around (TOGA);
— climb or maximum continuous thrust (MCT), N1 or EPR targeted (THR CLB, THR MCT, N1, THR HOLD, EPR);
— speed (SPEED, MCP SPD);
— idle thrust (THR IDLE, RETARD/ARM);
— landing (RETARD, THR IDLE).”
(03) “Describe the two main variants of autothrust systems:
— mode selections available on the FCU/MCP and thrust levers move with autothrust commands;
— mode selections made using the thrust levers which remain static during autothrust operation.”
(04) Explain how flight in turbulence/wind shear giving fluctuating airspeed indications may lead to the autothrust overcompensating in an oscillating manner and that manual thrust may be required to settle the airspeed. Airspeed indications/trend vectors may give an indication of appropriate thrust adjustments but any reaction should not be too aggressive.
(05) Explain the threats associated with the use of autothrust resulting in the pilot losing the sense of energy awareness (e.g. speed, thrust).
Syllabus reference BK Syllabus details and associated Learning Objectives
(06) Explain the relationship between autopilot pitch modes and autothrust modes, and how the autopilot and autothrust will interact upon selecting modes for one of the systems.
(07) “Explain the principles of speed control and how speed can be controlled:
— by varying the engine thrust;
— by varying the aircraft pitch.”
(08) “Explain the potential implications on speed control when the autothrust controls speed and the autopilot pitch channel has a fixed pitch target for the following mode combinations:
— MCP SPD/SPEED and ALT HOLD/ALT;
— MCP SPD/SPEED and VSP (climb);
— MCP SPD/SPEED and VSP (descent).”
(09) “Explain the potential implications on speed control when the autothrust has a fixed thrust target and the autopilot pitch channel controls speed for the following mode combinations:
— N1/THR CLB and LVL CHG/OP CLB;
— ARM/THR IDLE and LVL CHG/OP DES.”