1 choose IAS DISAGREE alert is not shown, and then:

2 Verify all altimeters are set to correct barometric setting.

3 choose DISAGREE alert stays illuminated:

and here is the thing, WHY 4 Standby altimeter is available?

How to know standby altimeter is available?

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1 Answer 1


That statement is a reminder that you have the standby altimeter available as a resource. It's not accurate enough to allow you to stay in RVSM airspace, but it may be a tie-breaker between the disagreeing instruments. And for a crew that is so focused on the displays and wanting to sort our what should be believed and what should be ignored, that sort of a reminder may be what's needed in the stress of the moment.

  • $\begingroup$ This is a great human factors answer! $\endgroup$
    – wbeard52
    Commented Apr 15 at 16:33

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