Originally Posted by
tcasblue
Thanks,
Appreciate the replies. Hoping for a little more technical input about the IRS.
Little bit more info on the ADIRS that I can share.
The ADIRS calculates Inertial Vertical Speed and Baro Inertial Altitude. This Inertial Vertical Speed is what is shown on your PFD. It is not compensated for placement offsets wrt the C of G, a sudden rotation of the aircraft around the y axis (pitch up maneuver) will show as non zero V/S on the PFD.
The Baro Inertial Altitude is basically barometric altitude from the static ports augmented with the Inertial Vertical Speed. The latter is important since the V/S needs to be reflected on the Altitude Tape and vice versa. Also, integrating Inertial Vertical Speed to augment Barometric Altitude allows for a very quick and responsive altitude tape. Barometric sensors have considerable lag due to heavy filtering and their mechanics.
The filter loop is designed such that the altitude tape will always converge to the barometric altitude. Integration errors (due to accelerometer imperfections) will not result in a diverging altitude over long flight (obviously).