The ATR-72 has these 3 holes at the right front of the fuselage. They are marked as Captain, F/O and StandBy. It says do not obstruct, and the area inside the red lines must be smooth and clean. What are these for?

Holes in the fuselage

  • $\begingroup$ The "static ports" are used to measure static pressure. Static pressure is the name for pressure of calm air (excluding any effect of displacement), and is used, for example, to determine altitude or vertical speed. This is not very well explained in the linked question. $\endgroup$ – mins Jun 29 '17 at 9:53
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    $\begingroup$ @mins Fair point. But they're clearly labelled and Wikipedia will already tell you what a static port is. $\endgroup$ – David Richerby Jun 29 '17 at 9:54
  • $\begingroup$ @DavidRicherby: I don't disagree, just mentioning before voting to close. $\endgroup$ – mins Jun 29 '17 at 9:58
  • $\begingroup$ Why the downvote?? The question itself isn't bad and being a duplicate isn't a negative unless it shows no effort at all. $\endgroup$ – Notts90 supports Monica Jun 29 '17 at 11:20
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    $\begingroup$ I guess the OP didn't understand "static ports" as a name of a thing? $\endgroup$ – StarWeaver Jun 29 '17 at 13:42