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Autothrottle Controller

Technical Information

Catalogue No: C1087
Category: Engine Control
Object Type: Control/Data Entry
Object Name: Autothrottle Controller
Part No: 10910-A-1
Serial No: 022/71
Manufacturer: Elliott Bros (London) Ltd
Division: Unknown
Platform(s): A-6 Intruder
Year of Manufacture: circa 1971
Dimensions: Width (mm): 105
Height (mm): 145
Depth (mm): 200
Weight (g): 2,120
Location: Triple Shelf Unit, LH (control panels) [Main Store]
Inscription(s):

Elliott
Type No 10910-A-1
Ref. No
Ser. No 022/71
[Mods] 0, 1, 2, 3 & 6

Notes:

The unit bears the maintenance marks (in ink): "EBL.R.3.85"
and inspection stamp: "GAv(R) A.S.& R.D. 25"

An autothrottle (automatic throttle, also known as autothrust, A/T) is a system that allows a pilot to control the power setting of an aircraft's engines by specifying a desired flight characteristic, rather than manually controlling the fuel flow. The autothrottle can greatly reduce the pilots' workload and help conserve fuel and extend engine life by metering the precise amount of fuel required to attain a specific target indicated air speed, or the assigned power for different phases of flight. Autothrottle and AFDS (Auto Flight Director Systems) can work together to fulfill the whole flight plan.

There are two parameters that an Autothrottle can maintain or try to attain: speed and thrust.

In speed mode the throttle is positioned to attain a set target speed. This mode controls aircraft speed within safe operating margins. For example, if the pilot selects a target speed which is slower than stall speed, or a speed faster than maximum speed, the autothrottle system will maintain a speed closest to the target speed that is within the range of safe speeds.

In the thrust mode the engine is maintained at a fixed power setting according to the different flight phases. For example, during takeoff, the Autothrottle maintains constant takeoff power until takeoff mode is finished. During climb, the Autothrottle maintains constant climb power; in descent, the A/T reduces the setting to the idle position, and so on. When the Autothrottle is working in thrust mode, speed is controlled by pitch (or the control column), and not by the Autothrottle. A radar altimeter feeds data to the Autothrottle mostly in this mode.

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