A330 Standby Instruments

[extricate]

Hi there,

One ques, the standby instruments on the A330 gets its information directly from the sensors instead of the ADIRU? Is that right?

[macdo]

As I understand it, traditional SBY ASI and ALT are supplied by the respective SBY Pitot and Static sources.
The SBY Horizon is a simple electrical one supplied by the DC Essential bus.

If you have ISIS (LCD panel) sby system, it come from all the above plus ADIRU 1 and 3 plus Hot Bat Bus.

[emergency000]

I believe the ISIS also has its own dedicated battery.

[KingAir1978]

The Air Data comes from dedicated ports and pitots. The only reason the ISIS is also connected to ADIRU 1/3, is for the temperature, so it can calculate a Mach number.

[A33Zab]

@KingAir1978:


The only reason the ISIS is also connected to ADIRU 1/3, is for the temperature, so it can calculate a Mach number.


Mach calculation is derived from Pitot and Static pressure, no need to supply a separate Temp. signal.
https://upload.wikimedia.org/math/1/3/6/136b9276ef7cc3bc2103eb72ab609ebf.png

ISIS initializing can take 90 sec. during this period airspeed is supplied by ADIRU 1/3 depending on position of ATT/HDG selector switch.

@Emergency000:

I believe the ISIS also has its own dedicated battery.

Back-up power supply is BAT HOT BUS, no separate dedicated battery involved.

[vilas]

All pressure data goes to ADM and then to respective ADRs and then goes to PFDs. In case of ISIS stand by Pitot and standby static goes straight to ISIS without going through ADMs.