4
$\begingroup$

On the EFIS of Airbus you can see 1FD2 on the autopilot section of the FMA. what does it mean?

$\endgroup$
10
$\begingroup$

It means that both Flight Directors are engaged:

Flight Director (FD) Engagement

The FDs are engaged automatically whenever the FMGC powers up.

Ground Engagement

  • The symbol "1FD2" appears on both PFDs.
  • No FD bars appear on the PFDs. The PFD displays FD orders when a mode is active on the corresponding axis.
  • The FCU windows display dashes.

(A320 FCOM Autoflight - Flight Guidance)

It will look something like this:

1FD2

The pilots can disengage one or both FDs. In this case -FD2, 1FD- or nothing will be displayed.

Manual Flight Director Disengagement

One FD off:

  • The FD bars no longer appear on the associated PFD.
  • The corresponding FD is disengaged.

-FD2

Both FDs off:

  • The FD bars disappear on both PFDs.
  • If no AP was engaged, lateral and vertical modes disengage. The A/THR, if active, automatically reverts to (or remains in) SPEED/MACH mode.
  • If one AP was engaged when the FDs are switched OFF, this AP remains engaged in the active modes but the FDs are no longer displayed.

FDs off

If one FD fails, the other one will be used to provide guidance on both PFDs. In this case 1FD1 or 2FD2 will be displayed.

Automatic Flight Director Disengagement

If one FD fails or one FMGC is not valid, both PFDs display the remaining FD.

2FD2

$\endgroup$
  • 2
    $\begingroup$ To add: 1FD1 means both the captain and first officer PFD receive information from the flight director 1. 2FD2 means both use flight director 2. This is the case e.g. if one FD has a malfunction $\endgroup$ – Jan Jan 2 at 16:16
  • $\begingroup$ @Jan Thanks, I added it to the answer. $\endgroup$ – Bianfable Jan 2 at 16:56
  • 1
    $\begingroup$ @Jan Yes, this site lists them all but I'm not sure how authoritative the site is. It seems to be a preview/demo of their smartphone app about A320's displays and panels. But it looks good, though. $\endgroup$ – PerlDuck Jan 2 at 17:07
  • 1
    $\begingroup$ @PerlDuck My quotes and images are all from the FCOM. Interestingely, the FCOM as far as I could find does not mention modes like 2FD-, but that does not mean they don't exist. It would make sense after all... $\endgroup$ – Bianfable Jan 2 at 17:12
  • 1
    $\begingroup$ From a technical standpoint this makes sense: Dash = this side FD is not selected on by the pilot. 1 = FD1 powers this side. 2 = FD2 powers this side. Default is 1FD2, so left is FD1, right is FD2. If one FD has a fault both see the remaining FD. So 1FD1 and 2FD2 should exist as well as 1FD-, -FD1, 2FD- and -FD2 (when one pilot selects his/her FD to off. -FD- is not displayed afaik. $\endgroup$ – Jan Jan 3 at 17:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.