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On Airbus aircraft what is the 3 click tone that sounds once autopilot is disconnected? I have tried researching on the internet but could not find anything

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  • $\begingroup$ To inform the crew the A/P is now inactive? Disconnection may result from a fault, or an unintentional action. $\endgroup$ – mins Jul 6 '17 at 7:00
  • $\begingroup$ Hi. Welcome to Aviation.SE. I'm sorry, but we seem to have been suddenly invaded by downvotopaths. What's wrong with this question?. +1 from me since I see this as a perfectly legitimate question and just to restore the natural balance of the stack-o-verse. $\endgroup$ – Simon Jul 6 '17 at 7:39
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    $\begingroup$ Are you looking for a recording of the sound? $\endgroup$ – Koyovis Jul 6 '17 at 9:45
  • $\begingroup$ I believe that sound was invented by Airbus specifically for signaling autopilot disconnect. $\endgroup$ – kevin Jul 6 '17 at 10:21
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    $\begingroup$ If you can include a link to a YouTube video and a marker of the sound you're describing, that would make the question much more clear. $\endgroup$ – kevin Jul 6 '17 at 11:40
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There are two separate aural warnings that you might be referring to: one is indeed called 'Triple Click' and consists of three brief clicks, but is emitted when the landing capability becomes degraded or the autopilot otherwise changes mode.

The warning generated upon autopilot disconnection, instead, is the so-called 'Cavalry Charge' and consists of three longer beeping sounds; it's either played once or repeated continuously (cases 1 and 2 below).

From a table in the Airbus A320 FCOM, DSC-31-10 P 4/6:

TRIPLE CLICK

Meaning: Landing capability downgrade or some cases of mode reversion.

Duration: 0.5 s (3 pulses)

CAVALRY CHARGE

Meaning:

  1. A/P disconnection by takeover push-button.
  2. A/P disconnection due to failure.

Duration:

  1. 1.5 s
  2. Permanent

Cancellation:

  1. Second push on takeover push-button.
  2. Press Master Warning light or takeover push-button.

See this YouTube video (at 2:52) for a cavalry charge immediately followed by a triple click (thank you Jack).

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  • $\begingroup$ youtu.be/XU3B8Qq1niY This video at 2.55 $\endgroup$ – Jack Jul 6 '17 at 14:56
  • $\begingroup$ Any idea why they call that a "cavalry charge?" It doesn't really make me think of the standard bugle charge. $\endgroup$ – TomMcW Jul 6 '17 at 19:57
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More generally, the Flight Crew Techniques Manual describes the TRIPLE CLICK as:

...an attention-getter, designed to draw the flight crew's attention to the FMA.

The FMA will show a mode change or reversion by putting a white box around the new mode and pulsing the associated FD bar.

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