Hi Lyman;
...just plain old PJ2 is fine, ;-)
Re the wager, being a pilot I don't bet on things but thank you for reminding me of the information (on page 10!).
The loss of the VS parameter & displayed information is a possibility that I discussed in a previous post in re the "baro-inertial calculation and if supplied by a malfunctioning ADR, could return "NCD" and not be displayed. From the IR3, Appendix 1, p94:
@ 02:11:45
The vertical speed is no longer
calculated by the IR (Inertial
reference) but by the ADR. It is
about -10,000 ft/min.
This is coincidental with four ACARS messages indicating events occurring at 02:11:45, (and recorded/time-stamped between 5 & 29 seconds later) which also coincides with the disruption, as discussed above, of a number of parameters including the VS traces:
02:11:45 FLR/FR0906010210 34111506EFCS2 1,EFCS1,AFS,,,,,PROBE-PITOT 1X2 / 2X3 /1X3 (9DA),HARD
02:11:45 FLR/FR0906010210 27933406EFCS1 X2,EFCS2X,,,,,,FCPC2 (2CE2) /WRG:ADIRU1 BUS ADR1-2 TO FCPC2,HARD
02:11:45 FLR/FR0906010211 34220006ISIS 1,,,,,,,ISIS(22FN-10FC) SPEED OR MACH FUNCTION,HARD
02:11:45 FLR/FR0906010211 34123406IR2 1,EFCS1X,IR1,IR3,,,,ADIRU2 (1FP2),HARD
02:11:55 WRN/WN0906010211 341200106FLAG ON CAPT PFD FPV
02:11:58 WRN/WN0906010211 341201106FLAG ON F/O PFD FPV
02:12:02 PF states “I don’t have any more indications”; PNF, “We have no valid indications” Thrust levers to IDLE; N1s @ 55%
02:12:17 PF makes ND inputs; AoA decreases, speeds become valid again, stall warning sounds again
02:12:47 WRN/WN0906010212 341040006NAV ADR DISAGREE
02:13:32 PF: “we’re going to arrive at level one hundred”
When the PF says (likely to the captain), "I have a problem it's that I don't have vertical speed indication" and "I have no more displays" I do not think he means that his entire PFD is blank. From his comments, he still has attitude & altitude information and the altitude information is unwinding at a thousand feet every three seconds or so at that point in the stalled descent.
The overarching point, to which I am addressing my comments, that the displays were blank prior to the apogee and during the entry into the stall, and are somehow causally linked to the ensuing loss-of-control, stall and descent, is incorrect. Post full-stall and at high-pitch/high-descent rate, any number of indication & system anomalies are likely going to occur, which may lead a crew who may be continuing to believe that the aircraft (the wing) is still flying, to significant cognitive dissonance and an inability to construct a model of aircraft behaviour such that the way to a recovery could be seen. These are CRM as much as SOP matters, a subject which I expect to be dealt with in depth when the final report is issued.
Last edited by PJ2; 28th Mar 2012 at 00:53.