View Full Version : A320 Beta Target

2nd Jul 2011, 12:39

Question regarding ELACs and Beta Target on A320/321.
Scenario - ELAC 1 U/S at dispatch (permitted acc. MEL)
Engine failure on T/O.
When Beta Target becomes active, indication turns blue but sticks and does not react to rudder input.

Is this behaviour correct?
What does ELAC 1 provide to help in the calcuation of the beta target?
Why does ELAC 2 not take over this functionality when ELAC 1 is U/S?

All info gratefully received.


2nd Jul 2011, 20:12
Is that an experience or it is supposed to happen that b target freezes in an engine failure when ELAC 1 is u/s?

ELAC 1 and 2 gives turn coordination and yaw damper commands to the FACs. FAC 1 executes.

something else went wrong

2nd Jul 2011, 21:54
I observed this in a sim but question whether the behaviour is correct or not. No other malfunctions were active. Could be a sim logic problem or it could be like that on the aircraft. Need to find out one way or the other.

3rd Jul 2011, 08:07
Hi there!

As far as I am concerned, ELAC 2 would send enough information to FAC 1 to execute the Beta Target correctly. it could be a Sim glitch... especially because it doesn't mention anything in the ELAC 1 MEL about possible effects on the Beta Target.


3rd Jul 2011, 10:46
I can't see how things happen exactly:

ELAC 1 lost, then ELAC 2 sends yaw orders to FAC 1, and FAC 1 controls rudder?

or ELAC 2 sends orders to FAC 2 and FAC 2 controls the rudder?

anyway, it looks like a glitch.

by the way, which computer actually calculates beta target? FAC?

Last Ditch
9th Jul 2011, 13:38
FAC does the beta target. My guess is that ELAC has no role in it, unlike in turn co-ordination.
Even small lateral sidestick inputs can make beta target very sticky.