Hi Takata,
Well in fact this question was raised by me.......and I did read the full reports but maybe I did missed this one.
Ok, try to formulate it another way.......for what reason could Inertial Data be not available?
IR part of ADIRU can operate normal even if ADR is providing unreliable information.
Quote:
FCOM
1.31.40
INDICATIONS ON PFD
VERTICAL SPEED:
The displayed vertical speed information is normally based on both inertial and barometric data.
If inertial data is NOT available, it is automatically replaced by barometric information.
In this case, the window around the numerical value becomes amber.
