On our mixed fleet of 744's, Body Gear Steering works just fine, every time during maintenance tows with all 3 IRU's switched off.
Seems to find a way to satisfy whatever arming logic there is.
I realise having them "off" is different than having them "on yet failed" I.E EICAS message present.
Would have to do some digging in the manuals to get to the bottom of it.
Last edited by Spanner Turner; 15th Feb 2018 at 03:05.