« Previous Next »

Autothrottle Computer Amplifier

Technical Information

Catalogue No: C0202
Category: Engine Control
Object Type: Signal/Data Processor
Object Name: Autothrottle Computer Amplifier
Part No: 5048-A-1
Serial No: 001/66
Manufacturer: Elliott Bros
Division: Unknown
Platform(s): BAC 1-11 
Year of Manufacture: 1966
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Main Object Store

Autothrottle Computer Amplifier
Type No. 5048-A-1
Ref No.
Ser No. 001/66
[Mod Status] A
Flight Test Only


The Autothrottle Computer Amplifier is a 3/8 ATR Short box containing the electronics necessary for computing autothrottle demands. The Autothrottle system operates the pilot’s throttle levers to control thrust according to Indicated Airspeed or Mach Number. An alternative control to Angle of Attack command was possible. At the time the Autothrottle Computer Amplifier was made in the Transport Aircraft Controls Division of Elliott Bros.

The BAC 1-11 AFCS, like that in the VC10, was based on the well proven Bendix PB-20 Autopilot and was designated the Series 2000AFCS. New features over the PB-20 system include separate pitch and azimuth control computers, a modular Air Data Sensor and a range of units specifically designed for autoflare and autolanding.

Each unit in the BAC 1-11 AFCS is built to a common configuration with circuit modules arranged in stacks either side of the chassis. The stacks are connected by plugs to a mother board and are physically separated into ‘command’ and ‘monitor’ functions to preclude common failures. The computers are entirely solid state and there is a high degree of built-in-test. Self-monitoring techniques and multiple channel redundancy are used to give automatic failure survival in approach and cruise flight.

Click to enlarge Click to enlarge