oilygreasemonkey, various AFS components will have been disturbed and new wiring installed for the MRTT modification. Even just the modified FCU amounts to AFS modification - and was discussed with the AAR community well over 10 years ago now.
The KC-30A AFS modifications probably include the tailstrike prevention, AAR CG protection and RCVR FCTL modifications. Whether these software modifications are resident, but inactive in the Voyager AFS, I do not know. But the AFS cannot be considered to be identical to the 'green' aircraft.
Barring aircrew or maintenance error, an AFS software bug or some form of installation error (wiring....perhaps) seem the likely culprits.
The QF72 incident led to significant modification and additional procedures long before Voyager appeared on the scene, so it is unlikely that any parallels can be drawn with that incident.
Last edited by BEagle; 15th Feb 2014 at 08:17.