Gentlemen,
if I may, I intend to shed some more light on this touchy matter of Flight Control Laws on the accident type.
Each Flight Control Primary Computer will perform its own computations, and decide its own Flight Law, based on available data. FCPCs (or PRIMs) manage Normal and Alternate laws, while FCSCs (or SECs) manage Direct law. The Master PRIM (normally PRIM1) then decides which Law gets used for the whole system.
Lemurian wrote :
the whole system reverted back to the pilots with an ALT2 FC law
This is unfortunately not accurate enough in our case. I urge you to reconsider the very particular case of FCPC n°2, after it lost connectivity with ADR1 following this failure :
02:11:55 EFCS1 X2,EFCS2X,,,,,,,FCPC2 (2CE2) / WRG:ADIRU1 BUS ADR1-2 TO FCPC2, HARD
This is definitely a wiring fault, where FCPC2 and ADR1 lose their connection.
Lemurian, could you be so kind as to demonstrate with certainty that FCPC2 reached indeed a state where it operated in Alternate 2 law ? I am not so sure. Normal law would be the preferred mode even with only two ADRs, as long as they produce similar values.
FCPC1 certainly did operate in ALTN2, as correctly demonstrated by BEA in its intermediate reports. It was Master PRIM until it failed along with its SEC1 partner :
02:13:45 F/CTL PRIM1 FAULT
02:13:51 F/CTL SEC1 FAULT
Then FCPC2 became Master of both elevator halves and THS.