A320 ADIRS 3 minutes before shut-off

[Skipping Classes]

Hi,

All experienced A320 pilots know that you should wait for at least three minutes after the aircraft complete stop before switching off the ADIRS.

If you don't - you will most likely get an align problems due to incorrect position memorized by the ADIRS at shut-off and possibly will have to shutdown the aircraft completely to reset everything. (Sometimes pulling
the ADIRS circuit breakers for 3 minutes helps too)

All this confirmed by experience yesterday ;-)

Now the question is where can this 3 minutes delay before shutdown can be found in the FCOM's?

The only reference I can find is US Airways unofficial Airbus A320 Notes, saying:

"Note: DO NOT move aircraft during alignment. Wait 3 minutes after aircraft
stop to re-align or turn off (PH 3.4.1, 3.16)"

FCOM 3.4.1 and 3.16 does not contain anything relevant to this topic.

Any idea what is this PH 3.4.1 and 3.16 are?

Thanks in advance and remember not to shut-off the ADIRS within 3 minutes after a/c stop! ;-)

Cheers,

SC