Non-conforming Failure
When the ACARS report shows ADR Fail, it does not have to be all the outputs failed, just any single output. Failed airspeed calculation does not cause a fail of the altitude output.
I'm still perplexed by the TCAS Fail report in the list. ATC/TCAS use altitude, not airspeed. The other incidents did not mention loss of altitude display. In one instance, it was noted the altitude indicated a drop of 300 feet, meaning the ADR was still outputting valid altitude calculation, but perhaps without airspeed trim.
Last edited by Jetdriver; 26th Jun 2011 at 10:18.