Dutch Bru;
Combined in a series 7 to 10, the SIGMETs show highly dynamic, intense and widespread EMBD TS activity in the ATLANTICO FIR on the foreseen route. Had the AF447 f/c availed about the full series through ACARS, they could probably have been on higher alert as to penetrate the zone concerned and perhaps used the wx radar more optimally.
Flight crews avail themselves of ACARS met reports all the time. In my experience, company dispatch provided timely and up-to-date information on SIGMETS as a matter of flight following, a legal and operational requirement in many states. Most crews would plot the SIGMET'd area on their planning charts then keep a wary eye using all available techniques including radar. That is not where the problem lies. The problem is in teaching how to use the radar "optimally". Likely, most pilots pick up the use of their radar through "osmosis", which does not filter misunderstandings and shortcomings in knowing one's equipment.
Rananim;
What if rollback or stall preceded flameout?GCB still closed but bleed flow to packs disrupted to trigger the last ACARS.
Sorry, do you mean "stall" of the engine or of the aircraft? I'll assume engine for now,
. A stall of the aircraft at that point, (powered), would generate ACARS messages, and we see none.
Logically, this scenario, (engine rollback/stall, then cabin pressure message) can't work because there would (likely, but not necessarily) have been messages indicating engine "failure". It depends - the word "rollback" means the inability to accelerate the engine but it's still turning, burning and hydraulic-ing - so the possibility, (but not the probability) is there.
As to the "what then"...well,I dont think the lack of any distress call is too big an issue considering where they were.
It is not an issue at all. Those who are either confused by the absence of such a call or are mildly chiding/merely "observing" the absence of a call don't understand the swiftness of what happened in the cockpit and what ensued. The crew would have been struggling to maintain situational awareness and discipline in a very serious, rapidly degrading circumstances. The judging of this absence is therefore wholly inappropriate; even the notion that an "automatic" distress call could be sent is naive.
The lack of LJ's?Failure to re-light?Bodies were found with no clothing.If bodies had been found clothed but with no LJ,yes.Re-light requires flt envelope check which requires reliable instrumentation.Dark night,bad weather etc.
Absence of any life-jackets in use is evidence for swiftly overwhelming events in which there was no time to prepare for the emergency.
Relights folllowing crystalline icing are 100% from what Ive read so yes its still a tenuous theory.
I fully agree. Just to be clear, it is not my theory, nor do I support the view that the engines flamed out due to ice crystals. The 330 has flown thousands of hours through "ice crystals" in high altitude layers without result. I've flown in "ice crystals" throughout the career without result in terms of engine roll-back or upset.
To recall the point, if the aircraft lost sufficient speed to enter a stall and the BEA has concluded that impact was of a flat aircraft attitude, high-velocity, vertical trajectory nature, then I submit that due to the very high angle of incidence in such a trajectory, the engines would have flamed out. I submit that the ACARS cabin advisory message was due to the effects of degrading upstream monitoring processes rather than a compromise of the cabin structure at that point or the loss of bleed-air input into the cabin to maintain pressurization. The BEA report does not comment on this message and so it is entirely conjecture.