I am really curious as to what the “green/red” strip of led indicate and the numbers below it. Having read around the web, i speculated that it could be an audio quality rating scale. Would help alot of someone could please help explain the “numbers” and why there is so many led blocks on the strip...enter image description here

  • $\begingroup$ There are a number of different CVR models out there, which one is this specifically? $\endgroup$
    – Ron Beyer
    Commented Jun 25, 2019 at 15:09
  • $\begingroup$ Looks like a newer Airbus CVR panel. The test button generates an internal low frequency test tone signal and the LED will tell you the quality of the audio picked up by the CVR when the tone is generated. The tone is internal and can only be heard if you plug in a headset into the headset jack. A good test will indicate in the green, the more green, the better the test result. On the A320 the tone is heard over the cockpit speakers. $\endgroup$ Commented Jun 25, 2019 at 15:44
  • 1
    $\begingroup$ @RonBeyer i am not too sure about the model, but its from A330-300 $\endgroup$ Commented Jun 25, 2019 at 16:19
  • $\begingroup$ @JuanJimenez By any chance do you know the meaning of the “numbers” below the strip? 0.3-1.15? So could you say, a new plane (if tested on the CVR) would get a full green led on the strip? $\endgroup$ Commented Jun 25, 2019 at 16:24
  • $\begingroup$ I have not been able to find any other example of a panel with the numbers, let alone an explanation. Sorry. I am also not 100% sure of the details, which is why I posted as a comment and not an answer. But if I had to guess, the numbers may be referring to the measurement of the frequency of the tone and how it compares to what the ideal measurement should be. But that is only an educated guess. $\endgroup$ Commented Jun 25, 2019 at 18:04

1 Answer 1


I could not find the exact model you showed, but the A330 and A340 FCOM on SmartCockpit shows a similar one. Unfortunately the description of the test is rather short:


The Overhead Pushbutton explanation on SmartCockpit is equally short:

A330 Overhead Pushbutton Explanation

My best guess would be that it shows the recorded volume from low on the left to high on the right and it is considered OK (test passed) if it reaches into the green LEDs, therefore making sure the CVR can pick up voices clearly enough. I hope someone working with these CVRs can provide a more accurate answer!


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .