Hello,
This is a joint effort at describing what the messages tell us.
It's about how these ACARS messages could have been translated into the flight-deck environment and the piloting issues that we could see. I tried to keep as factual as possible except in two cases where there is some uncertainty as to the meaning of a message.
I also refrained from speculating as to the check-lists they could have performed, except the "unreliable airspeed" QRH procedure.
THE COCKPIT ENVIRONMENT
AUTO FLIGHT AP OFF : Red Master Warning light / Cavalry Charge
REAC W/S DET FAULT : Red Flag on PFDs
F/CTL ALTN LAW : Amber Master Caution / Chime
Flags on PFDs : Red “FD” Flags on PFDs
AUTO FLIGHT ATHR OFF : Amber Master Caution / Chime *
NAV TCAS FAULT : Red Flags on PFDs / NDs
Flags on PFDs : Red “SPD LIM” Flags on PFDs
F/CTL RUD TRV LIM FAULT : Amber Master Caution / Chime
Flags on PFDs : Red “FPV” Flags on PFDs
NAV ADR DISAGREE : Amber Master Caution / Chime
ISIS SPD/MACH Flags : Red Flags on ISIS SPD /Mach
IR2 FAULT : Amber Master Caution / Chime
(With extreme caution: It was only a “Maintenance Status at 0211Z,
If an ECAM fault was announced later, it would mean the loss of HDG
And ATT for the F/Os PFD and ND.)
F/CTL PRIM1 FAULT : Amber Master Caution / Chime
F/CTL SEC1 FAULT : Amber Master Caution / Chime
As one can see from this list, there is only one red warning : The Auto-pilot disconnect.
All the rest of the ECAM or PFD/ND messages are at a lower level and present no real urgency.
On the other hand, the annunciations, both aural and visual coming at a very high rate couldn’t have helped the crew to keep or regain any SA they had.
(*) See the A/THR issue below
FLIGHT MANAGEMENT AND PILOTING SITUATION
Task attributions in an abnormal situation are generally well defined in a modern flight-deck: One flies and communicates, the other manages the systems and the check-lists..
There is some uncertainty, though, as to who the “Pilot Flying” was. With the Captain in the LH seat, either one could have been it. During the Captain’s rest, only the most experienced co-pilot could have been PF and only from the RH seat, the second co-pilot being in charge of the systems, radio-com and navigation.(AF SOPs)
It was then up to him to keep an update of the weather at alternates, keep a sharp eye on the PETs between the alternates in an ETOPS environment, help with the radar… It’s also his job to compute at every reporting waypoint engine and speed parameters for turbulence penetration, altitude capability and possible step climb, the fuel situation…etc.,..
-What piloting instruments were available ?
It looks from the messages that they, quite early in the chain of events, lost SPEED and Mach information, both on the PFDs and the ISIS, and the FPV, flight path vector.
They, of course were without Flight Directors and auto thrust. The A/THR disconnect, apart from the amber caution light would have triggered a “Thrust lock” indication on the ECAM, indicating the need to use manual throttle.
Nothing else was lost…….until the possibility after 0211Z of an IR #2 failure, causing the loss of attitude and heading indications on the RH side. A “switching” to the IR #3 would have been needed to recover these indications on the F/O’s side.
The ISIS, also minus speed indication could have been used...but from the RHS ? Not easy and vertigo-inducing.
So, we’re left with the necessity of an “UNRELIABLE AIRSPEED INDICATION” check-list, in itself a non-event in most conditions. In this case, they had the speed, they had the thrust..just match the T/Ls with the present N1 and they would have been very close to the needed parameters for level flying at the same speed.
-Alternate Law handling issues.
With the “ADR DISAGREE” situation the flight control laws would have reverted to “ALTERNATE LAW 2”, with most of the envelope protections unavailable except the load factor in pitch.
-Roll Direct : there is a direct stick-to-surface relationship. All ailerons are available and spoilers 2, 3 and 6 are used for roll augmentation (until 0213Z that is, as the loss (?) of SEC1 would render spoiler #6 on both sides unavailable).But there is enough surfaces to guarantee a minimum of 20°/s roll rate if needed.
By personal experience, alternate law flying is hardly noticeable : the ailerons feel a bit heavier and slower to respond but that’s about it.