Gents just to shed some light:
Post#1910
The problem, as said earlier, is that ISIS containts are classified. I know it sounds weird but again, no one opens up this box !!
It is true ,that an ISIS falls under the US expert control request due to this fancy "inertial Measurement unit" but it can and will be opened for repair. Actual there is a reapir manual for this.
While it is true that it gets inputs from ADIRU 1 and 3, it is also true that it contains gyros !!
Not so true. It does not contain gyros. It's containing a IMU (Inertial Measurement Unit) described as "
Inertial Measurement Unit (IMU). It contains three single-axis rate sensors and their temperature
probes, two acceleration sensors and their temperature probes, one IMU board and one mechanical
structure. This assembly is connected to the Programmed Motherboard "
It is not an IRU (Inertial Reference Unit) it ONLY detect it's position in space, not movement in it. And in regards to ADIRU inputs.
ADIRU (IR1 or IR3)
Two ARINC 429 high-speed buses provide the ISIS indicator with the ADIRU ground speed information. This information is used as a backup source for the ISIS ground/flight condition.
In normal configuration, the parameters used by ISIS indicator come from the ADIRU 1.
When a failure is detected, switching to the ADIRU 3 must be done manually through the ATT/HDG selector switch on the SWITCHING panel.
But U can ask me every time 