Will Fraser:
Again, I think it likely some failure of the tail and/or aft pressure bulkhead occurred at high speed, post ACARS. Even if the tail failed during ACARS tx, is it not possible evidence was 'backed up'? Also, ACARS is mx, it doesn't troubleshoot? Rudder Travel Limiter loss could be its 'understanding' of a catastrophic empennage failure? Though the VS was gone, the ACARS may sense it as 'there goes the RTL'. With a loss of hydraulic pressure consistent with separation, its tx might be what ? If the VS loss happened when the ACARS was 'busy' or after 0214?
- 2723 Flight Control Ruder Travel Limiter Fault Cockpit Warning is documented beyond any doubt. RTL is a function of airspeed which fault once speed data became unreliable, then it is displayed in cockpit. This is totally unrelated with Hydraulic Systems and failures.
But one may decide that both CMS (Central Maintenance System) is unreliable and is displaying by ACARS some erratic faults unrelated to the right system in order to bend the facts to theory. Then, instead of displaying 29. Hydraulics faults on the three hydraulic circuits linked to the rudder (Blue (B), Yellow (Y), Green (G)), the faulty CMSs will use Flight Controls warnings instead.
With the possibility of statics problems and/or pressure loss in cabin, the warning may be doing its task as designed, 'faster than 1800'/min.' is consistent with a complete loss of pressure in the cabin, is it not?
What would be consistant with a complete loss of cabin pressure would be a 21. EXCESS CAB ALT, CRC aural Warning, Master Warning displayed, indicating that the Cabin altitude is exceeding 9,550 ft at cruise altitude.
The cabin vertical speed advisory (cockpit signal) is related to the controller ability to monitor the DeltaP (external and cabin differential pressure) changing in excess of 1,800 ft/mn. A change of aircraft indicated altitude (real or instrumental) would trigger such an advisory if the differential pressure is in excess of the function.
But one may follow the same logic as for the RTL and consider that as a major failure of the whole pressurization system, because the tail (fin) separated in flight... consequently,
"you will know it was deliberate and political".
S~
Olivier