How frequently are avionics on large commercial aircraft updated? And how are the systems updated?
Infrequently. Large fleets, lots of down time, lot of equipment to buy.
The fleets are cycled thru at a refittng center where the panels are disassembled and re-assembled. Here is one example
$\begingroup$ Though the post doesn't specify it is tagged with
software, which wouldn't necessarily require lots of new equipment. $\endgroup$– foootMay 17, 2018 at 19:41
$\begingroup$ Well, being a hardware engineer, I was looking at from the hardware perspective. I just had new hardware put in my airplane (solid state gyros, GPS/Nav/Com, Transponder, Engine Monitor). And today the software was updated in the gyros and GPS/Nav/Com, which I never had hardware before that could be updated like that. $\endgroup$ May 18, 2018 at 21:30
$\begingroup$ Even software doesn't get updated that often (Databases like maps are a different animal) For example, avionics company A might only put out a software update from 6 months to 2 years, depending on the product. $\endgroup$ May 19, 2018 at 19:50