PRIM 1 and SEC 1 Faults
Quote from Svarin (Apr12/1754z, currently #3387 on Page 170):
"02:13:45 F/CTL PRIM1 FAULT
02:13:51 F/CTL SEC1 FAULT
First, this describes a simultaneous failure of PRIM1 and SEC1, which greatly reduces the likelyhood of a manual shutdown or reset."
Your analyses in the area of possible wiring fault and possible pitch-up have been most thought-provoking. Thanks.
However, I'm not entirely convinced the two faults were necessarily (a) simultaneous and (b) "permanent" (for want of a better word).
Re my (a), I agree that SEC1 is probably below PRIM 1 in CMC transmission priority, so they might have been simultaneous. But could there not equally be a gap of up to (say) 11 seconds?
Re my (b), these are cockpit (ECAM) warnings that have sufficient maintenance implication to justify an ACARS message. The BEA comments, in both cases: "this shutdown could be the result of a command or of a failure."
Am wondering if the crew might have gone for a quick trip-and-reset (re-boot) on PRIM 1, followed almost immediately (not simultaneously) by the same action on SEC 1. (We used sometimes to resort to similar expedients in the early days on the A320. Don't know what current thinking on the A330 is, let alone SOPs – but they would have been out of the window by 0213z.)
If a computer had not displayed a FAULT W/L (warning light) prior to a crew-selected re-boot, the fault W/L and associated ECAM message might last for just a few seconds. The question is, would it subsequently be transmitted by ACARS? The other, remote possibility is that the crew might have left one or both PBs (push-buttons) in the OFF position, deliberately or otherwise.
CONF iture,
I agree with your above point that speed reduction to turbulence speed might have been in progress at 0210z, implying low N1. Just a reminder that the CF6 engine does not use EPR, N1 being the primary indication of thrust.
Chris