Air Data Computer

[akafrank07]

An abstract from 'ACE THE TECHNICAL PILOT INTERVIEW'

The advantages of the ADC system is that the data calculated can be feed to the following:

1. Autopilot
2. Flight director system
3. Flight management system
4.Ground proximity system
5. Navigation aids
6. Instrument comparison systems

What is number '6' relating to?

Thanks

[CAT3C AUTOLAND]

On the Airbus the Air Data Reference (ADR) is fed into multiple systems, to assess a number of parameters. Each Elevator and Aileron Computer (ELAC) and Flight Augmentation Computer (FAC), receive data for the Air Data References, to which there are 3 and they compare these values.

If there is an erroneous reading from say 1 ADR the ELAC and FAC will reject these inputs, and provide a FAULT message to the crew. In a nutshell these comparisons provide protection for things like unreliable airspeed, and allows the crew to switch to an alternate source as a back up.

Hope that helps.

[akafrank07]

Hi CAT3C thanks for the reply

On the Airbus the Air Data Reference (ADR) is fed into multiple systems, to assess a number of parameters. Each Elevator and Aileron Computer (ELAC) and Flight Augmentation Computer (FAC), receive data for the Air Data References, to which there are 3 and they compare these values.

If there is an erroneous reading from say 1 ADR the ELAC and FAC will reject these inputs, and provide a FAULT message to the crew. In a nutshell these comparisons provide protection for things like unreliable airspeed, and allows the crew to switch to an alternate source as a back up.

Hope that helps.
What is the difference between and air data computer and air data referance, because as far as i can work out they both do the same thing, only that the air data reference measures the aircraft's position?
Is there two air data reference installed on a aircraft?

[de facto]

air data reference measures the aircraft's position
No.Air Data is AIR data from your pitotS and static portS.
Aircraft position is calculated via Inertial Reference UnitS among others such as GPS.
To answer your question,if for example the air data computer of Captain gets info different from the ADC of the FO,the crews will be alerted as for example speed disagree as mentionned above.
The 737 has two AIr data computers linked to two Inertial reference units called ADIRUs.