Originally Posted by
nnc0
The final sequence of ACMS messages transmitted via ACARS was
ANTI ICE R WINDOW
R SLIDING WINDOW SENSOR
SMOKE LAVATORY SMOKE
AVIONICS SMOKE
R FIXED WINDOW SENSOR
AUTO FLT FCU 2 FAULT
F/CTL SEC 3 FAULT
I was considering the sequence of the faults/messages and the absence of some others and ignoring the AVIONICS SMOKE ECAM, it would lead one to suspect an avionics bay event that led to some kind of fire.
Following LAND ASAP in the QRH's SMOKE/FUMES/AVNCS SMOKE procedure, the next action states 'IF PERCEPTIBLE SMOKE APPLY IMMEDIATELY: '. The use of the word perceptible there is because in the case of AVIONICS smoke crew will likely smell the smoke before any ECAM warning is displayed. . The AVIONICS SMOKE detector is very slow to actually trigger an ECAM. I'm even suspecting the Lav smoke detector picked up smoke before the avionics detectors did.
(I had some initial speculations this might be an EFB issue (window mounted (iPad plugged into an 400 HZ f/d supply or some such other jerry rigged setup), which flared up and caused the WHC faults. Back in the day, prior to AIRBUS introducing the new LITHIUM PED FIRE procedure, some recommended moving the smoking device to the FWD LAV))
So while I'm inclined to think this is the result of some issue with, or upstream of, WHC 1 (or 2) and that the subsequent faults are probably related to the spreading fire, what I don't understand with that scenario is why there were so few ECAMS included in the ACMS ACARS msg. Surely there would have at least been a record of a ANTI ICE WNDSHIELD ECAM if that were the case?
ACARS, particularly their sequence in time, may be hard to understand from their very few lines displayed on screen, without their full headers, and sequential relations between them, including how they are supposed to be triggered (e.g. with or without delay, priority order, class, etc.).
Since we had AF447 ACARS discussed to death, we should be aware of that ACARS are designed to report "system fault" (and related message). Taken independently a "system fault" can cover quite a lot of events. First, it's hard to figure out the sequence of those events simply at looking at ACARS order, and next, it's hard to figure out what caused the fault to be reported without other data from the maintenance computer.
Nonetheless, ACARS are telling us that between take off and the end of the report :
1. this flight was uneventfull (system wise) until 00.26
2. events took place at cruise (6)
3. ACARS stopped at 00.29, hence 3-4 minutes of reporting.
Next, out of the ACARS report between 00.26 & 00.29, only "SMOKE" looks serious enough for causing the end of ACARS transmission 3-4 minutes later ; excepted from it, those ACARS are telling us that none of the aircraft vital system (and airframe) was actually compromised up to the end of transmission... because nothing else was reported than three minor "faults" up to 00.29. Whatever caused the loss happened after.
Also, whatever caused the smoke to be detected at the first place won't be read from ACARS only ; nothing can tell us if a system "faulting" is the cause or the consequence of a SMOKE event without any further data. So far, all we can do is to think about what action would take the crew while displayed "SMOKE" in lavatory then avionics :
