I'm looking at a picture of the electrical panel of a Phenom 100 and on it I see a + sign, does anyone have any ideas as to what it's supposed to mean?

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  • $\begingroup$ ymb1's answer is excellent, however I didn't fully understand what it meant until I saw this video. $\endgroup$ Commented Sep 19, 2017 at 17:32

1 Answer 1


enter image description here

Above I marked five similar plus signs on the 737 (there are more). Beneath the +'s are the contacts for the backlighting of each panel. If it acts up then pressing on the sign will ground/secure the connection and may solve the issue.

The electroluminescent light-panels are flexible and the ride can be too bumpy sometimes. Better push the right spot than wait for a specialized someone on the ground who knows where each contact is.

enter image description here
Composite based on images from b737.org.uk.

  • 44
    $\begingroup$ I'm not sure if that's amazing or terrifying $\endgroup$ Commented Sep 18, 2017 at 11:37
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    $\begingroup$ Can you explain that more? Why would the backlight “act up” and why would pressing on the + symbols resolve it? $\endgroup$
    – Michael
    Commented Sep 18, 2017 at 13:37
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    $\begingroup$ That's it, I'm taking the train next time! $\endgroup$
    – dotancohen
    Commented Sep 18, 2017 at 13:41
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    $\begingroup$ @ymb1 - not to drag this too far off topic, but I'm amazed that the panels are built in a way that would allow the contacts to "bump loose" due to some turbulence in the first place. Everything else is built with triple redundancy, but my dashboard lights can flicker out at any time? Especially a potentially high stress time like turbulence? $\endgroup$
    – FreeMan
    Commented Sep 19, 2017 at 12:00
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    $\begingroup$ Is there a little mark on the fuel gauge, too, to indicate where I should tap in case the indicated value is too low? $\endgroup$
    – Pavel
    Commented Sep 19, 2017 at 12:19

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