Hi Blujet,
Welcome back, sir.
Originally Posted by Blujet
@takata: I have been trying to get info about VS indication on PFD(not data) and could not find any tests (AMM) were this system is checked. Maybe you have another source?
Did you check 34-14-00?
In fact, the Vertical Speed displayed is either "baro-inertial" (not only inertial) or "barometric". My first guess, from graph, was that no inertial V/S data was displayed passed -10,000 ft/mn. But it is not correct. The word range is +/- 32,768 ft for baro-inertial v/s, and only +/-20,000 ft for barometric V/S.
So, in fact, the reason should be simply because all ADRs were rejected by they respective IRs (this 0211 FLR ACARS discussed previously). It will become NCD and replaced by ADR source V/S on PFDs.
- Inertial vertical speed (365) and inertial altitude (361) computation:
The IR software contains a baro-inertial loop to compute the Inertial Vertical Speed and Inertial Altitude. This loop permits to take advantage of the different qualities of the inertial and air data systems. The IR brings its better behaviour in dynamic maneuvers while the ADR brings its stability in time (no drift of the outputs like in IR).
The ADR source to be used is selected according to the configuration of the discretes described previously. When no ADR source is available, Inertial Altitude and Inertial Vertical Speed are sent with their status matrix coded NCD (No Computed Data).
The principle of the baro-inertial loop is given here:
