Autopilot

Concorde has two autopilot systems. But only one can be engaged at a time to operate the aircraft during its flight the second one is used for back-up purposes and therefore is available as a hot spare. Both systems will be engaged if the aircraft is carrying out an Auto Land, with the second system automatically available should the primary one fail. The autopilot has 5 horizontal and 12 vertical switches for modes of operations. Also on this panel is the altitude to fly to setting, which is used for the majority of the flight time. The autopilot cannot be used for take-off.

How it works

Concorde’s Auto land system is very sophisticated and can land the aircraft better than the pilot on many occasions. It does this by using the Airport Instrument landing System’s (ILS) Glideslope and Localiser to guide Concorde into the touchdown point. Just before landing, data from the radio altimeters are feed into the AFCS to flare and land the aircraft. The pilot, does however, have to stop the aircraft.

There are 2 ‘piano switches’ that are used to engage the Autopilot. These are solenoid latched and will only latch if all the supporting systems are functioning correctly; such as the Air Data Computers, Autostabilisation systems, navigation and compasses. The system will always engage in the heading and pitch hold modes, and can be easily disconnected from a thumb switch on the Yoke by the pilot

The autopilot controls on the AFCS panel

Top row;  Different autothrottle, horizontal and vertical modes

Bottom row;  This is where you would select headings, height and speed “ to fly to”. It also has six “piano switches that can select in or out in the autothrottles, autopilot and flight director systems when required. The flight director provides a visual indication on the pilot’s Attitude Direction Indicator (ADI – Artificial Horizon) what the autopilot would want to do if it were flying the aircraft under the current settings. The Flight Director (FD) is used when the pilot wants to hand fly the aircraft, but be guided by the autopilot. It displays 2 yellow command bars and an attitude display on the ADI, which the pilot would match with the aircraft’s movements.

HORIZONTAL AUTOPILOT MODES

HORIZONTAL AUTOPILOT MODES

INS;

This mode causes the aircraft to track between two waypoints that are being fed to it from the external Inertial Navigation System (INS)

TRK HDG; 

Track or Heading. The selector dial on the bottom row is either pulled for heading mode or pushed for Track mode, and the aircraft will follows the Track or Heading selected by the pilot on the dial. A heading will follow a compass direction, where as a Track will follow a direct route to the selected position taking into account wind speeds and so on.

VOR LOC;

If this is pressed it will causes the aircraft to turn and track the selected VOR beacon or localiser that has been selected. It’s a Prime mode and a small triangle under the button will light up when the capturing is in progress, when the beacon or localiser has been acquired the button will at that point light up.

BACK BEAM;

Technically this is not an Autopilot mode, it is in fact a Flight Director mode and will only operate when the Autopilot is disengaged. It permits tracking of a Back Beam localiser

AUTOPILOT VERTICAL MODES

AUTOPILOT VERTICAL MODES

 

 

 

 

 

 

 

 

 

PITCH HOLD;                                                                                                                     

This is the basic mode of the autopilot and will hold the existing aircraft pitch when engaged. It comes on as default when the Autopilot is engaged.

MACH HOLD;                                                                                                                     

This function will hold the current Mach number by pitch changes and not throttles changes. If the autothrottles are engaged they will take precedence and the autopilot will default to PITCH HOLD

MAX CLIMB;                                                                                                                       

This is selected at or near Vmo (Maximum operating speed) and will hold the airspeed to a figure around Vmo. As the speeds approached Vmo at the top of the climb it will disengage and hold the speed with pitch changes.

MAX CRUISE;                                                                                                                     

This engages shortly after Mach2 and is an extension of MAX CLIMB. It is normally used in conjunction with the autothrottles primed in MACH HOLD to keep he aircraft flying at Mach2.0.
If the aircraft begins to overspeed, due to temperature changes, the auto throttles will slow the aircraft down. Once back at the correct speed MACH HOLD will disengage and MAX CRUSE will re-engage. It also prevents the aircraft exceeding the maximum operating temperature (Tmo) of 127 degrees Celsius on the tip of the nose.

IAS HOLD;                                                                                                                         

Holds the current indicated airspeeds by means of pitch changes

ALT HOLD;                                                                                                                             

Holds the aircraft existing altitude.

VERT SPEED;                                                                                                                       

Sets up the aircraft to hold a vertical speed as set up on the vertical rate of climb indicator

ALT ACQ;                                                                                                                             

This is Similar to IAS ACQ on the autothrottles. A preset altitude to fly to can be programmed in on the selector, and when the ALT ACQ Button pressed the aircraft will fly to that altitude. The prime light will light during the operation and the button will itself light when the speed has been acquired

TURB;                                                                                                                            

Turbulence mode, only used in moderate or severe turbulence. It holds the existing pitch attitude and heading, it reduces the trim rate of the electric trim system to smoothen the ride.

LAND;                                                                                                                            

Automatic landing mode. When this is pressed the prime triangle will light. It causes the aircraft to capture the glide slope and track to localiser that has been selected. When the glide slope has been captured the button will light and the small triangle prime light under the button will go out. The VOR/LOC button will light when the localiser has been captured. During the capture process the prime light on VOR LOC will light. After LAND mode is selected the2nd autopilot can be engaged for redundancy

GO AROUND;                                                                                                                

Indicates an automatic go around has been initiated. This is carried out when more than 2 of the throttle leavers are moved fully forward in LAND or GLIDE Modes. It will pitch the aircraft up at 15

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