Auto Thrust System
AUTOTHRUST FUNCTION
The A/THR function sends a computed thrust command (thrust target) to the Full Authority Digital Engine Control (FADEC) for automatic engine control.
The A/THR functions are:
– acquisition and holding of a speed or a Mach number,
– acquisition and holding of a thrust,
– reduction of the thrust to idle during descent and during flare in final approach,
– protection against excessive Angle-Of-Attack (AOA) called alpha-floor protection, by ordering a maximum thrust when an alpha-floor detection signal is received from the Flight Augmentation Computers (FACs).
AUTOTHRUST LOOP PRINCIPLE
To get the A/THR function, the thrust target computed by the Flight Management and Guidance Computers (FMGCs) is chosen by the Flight Control Unit (FCU). Then each FCU processor sends, along its own bus, the thrust target to the FADEC via the Engine Interface Units (EIUs).
AUTOTHRUST ENGAGEMENT
The engagement of the A/THR function can be manual or automatic. The A/THR is engaged manually by pressing the A/THR P/BSW on the FCU. This is inhibited below 100 feet RA, with engines running.
The A/THR is engaged automatically:
– when the AP/Flight Director (FD) is engaged in Take-Off (TO) or Go Around (GA) modes,
– or in flight, when the alpha-floor is detected; this is inhibited below 100 feet RA except during the 15 seconds following the lift-off.
NOTE: To effectively have A/THR on the engines, the engagement of the A/THR is confirmed by a logic of activation in the FADEC.
When A/THR is engaged:
– the FCU A/THR P/BSW is lit,
– the engagement status is displayed on the Flight Mode Annunciator (FMA).
When engaged, the A/THR can be active or not depending on the position of the thrust levers. When engaged and not active, the thrust control is manual. The thrust is commanded according to the position of the thrust levers. When engaged and active, the thrust control is automatic. The thrust is commanded according to the A/THR computed thrust target.
AUTOTHRUST DISCONNECTION
A/THR disengagement can be manual or automatic.
A/THR is manually disconnected:
– either by pressing the A/THR instinctive disconnect switch on any thrust lever,
– or by setting all thrust levers to idle position,
– or through the dedicated FCU P/BSW,
A/THR is automatically disconnected in case of failure detection.
Credit : Riya Kumari
Sharing is Caring
The A/THR function sends a computed thrust command (thrust target) to the Full Authority Digital Engine Control (FADEC) for automatic engine control.
The A/THR functions are:
– acquisition and holding of a speed or a Mach number,
– acquisition and holding of a thrust,
– reduction of the thrust to idle during descent and during flare in final approach,
– protection against excessive Angle-Of-Attack (AOA) called alpha-floor protection, by ordering a maximum thrust when an alpha-floor detection signal is received from the Flight Augmentation Computers (FACs).
AUTOTHRUST LOOP PRINCIPLE
To get the A/THR function, the thrust target computed by the Flight Management and Guidance Computers (FMGCs) is chosen by the Flight Control Unit (FCU). Then each FCU processor sends, along its own bus, the thrust target to the FADEC via the Engine Interface Units (EIUs).
AUTOTHRUST ENGAGEMENT
The engagement of the A/THR function can be manual or automatic. The A/THR is engaged manually by pressing the A/THR P/BSW on the FCU. This is inhibited below 100 feet RA, with engines running.
The A/THR is engaged automatically:
– when the AP/Flight Director (FD) is engaged in Take-Off (TO) or Go Around (GA) modes,
– or in flight, when the alpha-floor is detected; this is inhibited below 100 feet RA except during the 15 seconds following the lift-off.
NOTE: To effectively have A/THR on the engines, the engagement of the A/THR is confirmed by a logic of activation in the FADEC.
When A/THR is engaged:
– the FCU A/THR P/BSW is lit,
– the engagement status is displayed on the Flight Mode Annunciator (FMA).
When engaged, the A/THR can be active or not depending on the position of the thrust levers. When engaged and not active, the thrust control is manual. The thrust is commanded according to the position of the thrust levers. When engaged and active, the thrust control is automatic. The thrust is commanded according to the A/THR computed thrust target.
AUTOTHRUST DISCONNECTION
A/THR disengagement can be manual or automatic.
A/THR is manually disconnected:
– either by pressing the A/THR instinctive disconnect switch on any thrust lever,
– or by setting all thrust levers to idle position,
– or through the dedicated FCU P/BSW,
A/THR is automatically disconnected in case of failure detection.
Credit : Riya Kumari
Sharing is Caring
