PJ2,
Thanks for the great scans.
Almost certainly. As we examine the ACARS messages for the traces of failure and/or system degradation, we must accept also, that either parts of the same systems remained operational without serious fault or the ACARS did not report any such faults in time.
Yes, I should have said operational HF
antenna, since that is what Mtc monitors in the tail. In my readings I came accross a comment that when the ACARS transmission fails (which Greenspinner says is attempted in microseconds after "Mother Computer" tells it what's wrong with the ship), then:
"The ACARS also contains protocols to support retry of failed messages or retransmission of messages when changing service providers."
Interfug asked if it's a complete list, So: How often does it retry? We know it got off what? 27 total faults and warns (including 3 mtc status wrns) for four minutes straight, so the acars system had normal DC and was functioning. I don't see how there could be any missing messages between 0210 and 0214z since ACARS breaks the info up into blocks (where's AVspook?, he probably knows the answer to this) This is the world of data bits and verification and secondary resends: only a real "TRON" can verify that when it's got a lock it's streaming fast. Wiki only says:
It should be noted that the majority of ACARS messages are typically only 100 to 200 characters in length. Such messages are made up of a one-block transmission from (or to) the aircraft. One ACARS block is constrained to be no more that 220 characters within the body of the message. For downlink messages which are longer than 220 characters, the ACARS unit will split the message into multiple blocks, transmitting each block to the RGS (there is a constraint that no message may be made up of more than 16 blocks). For these multi-block messages, the RGS collects each block until the complete message is received before processing and routing the message. The ACARS also contains protocols to support retry of failed messages or retransmission of messages when changing service providers.
System redundancies may or may not mitigate controllability issues.
What is the likelihood for example, that both TAT's would ice over at the same time? I realize that the theory on emergent warm air could make this question immaterial but we dont' know that and must ask the technical question.
Very high, if you know how to "sinc the props" and trim it straight,
, unless the fuselage is in a sideslip. It's an airmass issue. You've just hit humid icy warm (less than -40SAT) air. When it happened to me on the A310, all hell broke loose at once. Red Zippers, Stall Warnings, A/P disconnect, A/T to Thrust Latch. And no believable a/s anywhere. This was in the day. Ice was visable on both wipers. If the cause is warm air bubbles from King Neptune, then why aren't B747 guys loosing control? I'm suspicious it's more than just luke-warm/poorly designed pitot probes and static ports. It's gotta have something to do with the Airbus logic (born in the A300) when "Mother" the computer, encounters an event that engineers taught her was impossible.
Side note: we had alternate static port valves near your knee that could be opened on the A310. We didn't since I was hanging on for dear life and the F/O turned into Frosty. 3degrees and 90% worked and several minutes later in the clear probes melted it off and we wrote up a Aviation report and nobody believed us.
Has it been established beyond doubt that all three pitot heads failed within the four minute period and may be considered causal vice an outcome, in any theory? Even then, we do not know the failure mode...a complete loss of data or residual but degraded data?
Greenspinner seems to think so consulting his TSM. To me this means no loss of power to the ADIRU's but loss of just the
Air Data half that makes "Mother"
think it's failed. But Greenspinner said it looked like to him complete loss of the unit's power..... gulmp. (if I am quoting him right.)
Do the PFD faults indicate a serious failure or do the four (I think), ACARS messages indicate only one or two of the 24 possible fault messages concerning the PFD's?
Good Question. No PFD "Faults" that I can see. PFD
Warnings on the Cpts and F/O's PFD's. (Flag: something quit), (Flag: Something else quit) But if the IRU's went off line???????? Uh Oh.
I happen to think you're correct on the messages preceding the fatal loss of control but that is slightly redundant in the sense that a broken airplane can't send any more messages, (as per GB's comment on the fin), so what it DID send becomes extraordinarily important.
Yeah I know. You're probably right. But what's really stumping me, is: Can't a spiraling bus transmit a cabin decent ADVISORY out on ACARS through HF? I mean ACARs doesn't know it's in deep doodo. Power should have been good. HF should have been good down to break up (VS fin loss) or dual flame out. Right? Really high G's don't come till the attempted pull out?
Now we just need an Air France guy to confirm they have the HF ACARs augmentation option, and as you and Interfug said we need confirmation of any more messages from French TV2.
We need more leaks....
.