Originally Posted by
Speedwinner
And if it has no buss system? I would switch off a reliable alt indication…
You needed to provide following information in the original question:Whether aircraft had GPS?Whether aircraft had no BUSS, old BUSS or the new BUSS?since you have GPS but no BUSS you may keep the ADR2 but considering the complexity of the failure possibility of altitude becoming erroneous cannot be ruled out and CM1 doesn't have altitude on PFD anyway. So it's better to use GPS altitude from MCDU GPS page to fly the approach.