Hi Bearfoil,
Originally Posted by Bearfoil
Let me run past an elementary proposition, to see if, as a simple set, it establishes some foundation.
Three miles port side of the airway, at cruise, the pitots Ice, and airdata is lost. Due Unreliable Airspeed, the ADIRUS 'quit', auto flight/autothrottle are lost, Normal Law is degraded to Alternate, and the pilots need to quickly manage the a/c to retain control.
At least two automatically monitored reliable ADMs were needed to keep all flight enveloppe protections active, which was not the case anymore at this point (02:10). Then, most automatisms turned off, but were supposed in "safe mode" (A/P, A/THR, PFD, RTL,...), kicking ALT2 law, until the crew took some action by selecting which AS data was still to be considered reliable (by rejecting other). Note that this state (ALT2), once kicked on, can not be reversed until after landing. Then, the action required was for this crew to monitor all their informations about curent air speed after having selected a safe and defined pitch & thrust profile. This aircraft control
should not have been compromised by this event alone, meaning, an adequate crew reaction (or without reaction at all. In some other cases, they just did nothing until A/S anomalies ended by themselves).
Originally Posted by Bearfoil
The exact mechanism of LOC is not known, but the a/c contacts the water below, Belly down, Tail low, mostly intact, and is destroyed.
I'll add,
four or more minutes later, as the exact time for impact is still to be confirmed.
Originally Posted by Bearfoil
From the debris field, it appears that due to its very compact spread, there was little current to cause dispersion, but the direction of the current is suggested as East to West, and that if the debris field is searched further to the west, at some point debris would reach its ultimate distance from the heavier pieces.
No conclusion relative to the flightpath can be discerned from the orientation of the debris ?
No conclusion can be ascertained from the debris as to which direction the nose of the aircraft was pointed at impact ?
The impact point can be estimated to some degree with data known about the rate and distance of the sinking engines, by unwinding its path down ?
Well... the impact point was certainly very close to the vertical of those engines. Considering that below surface currents are negligibles for such a mass, they would sank straight down from where those impact forces will send them; mm43 observation is relevant: 35 m separation instead of the original 17 m or so under the wings.
I'm feeling that most of the wreckage at the bottom is somewhat related with the heading at impact (WSW), but it may be due to an illusion without having on hand the specific model showing all the mechanics involved.
Originally Posted by Bearfoil
The Captain's rest ended at 0200, and he was likely in the cockpit, perhaps even taking his Left Seat at the time of the Master Caution (Cavalry Charge), leaving only the F/O seated and restrained ?
Not so sure about that.
The contrary is more likely: taking one third watch for each pilot at cruise level (From departure FL200 to descent), The capitain being on the deck at both end, he will have watched the first cruise leg which might have ended around 0200.
Originally Posted by Bearfoil
The attitude excursions allowable by the a/p affect the ride of the a/c; did the a/p disconnect due its inability to manage the a/c ( Turbulence ), or due an already Unreliable A/S ?
Icy conditions (see my many posts about that) doesn't imply any level of associated serious turbulences. But ice issues are acertained by pitots fault, consequently A/P and A/THR certainly kicked off due to an unreliable airspeed event, freezing also the Rudder Travel Limiter at its cruise settings for Mach 0.82 cruise level flight.