For Thermalsniffer: thank you for addressing the "what were they doing just before things went all wrong" vis a vis comms. I had forgotten than from the earlier threads. That series of transmissions puts the "nodded off crew" as unlikely, though it doesn't address a course change in progress when an upset occurs ...
For Thermaller:
I have never piloted a powered aircraft but my issue here concerns commonsense rather than piloting skills.
Before we go further I will point out that if you are not familiar with what actually goes into flying, your attempt to apply "common sense" is an argument from ignorance.
When there is an accident there is more often than not some sort of human error involved. As a regular paying passenger I have to say that I have faith in the technology but grave suspicions about the people up front. Many correspondents to this forum will be flight crew and may like to comment on my concerns, which are as follows: to me it is almost inconceivable that a captain would take a nap during the time at which the plane is traversing the tropical convergence zone, where it is known by all that there is elevated risk. Surely commonsense would dictate that the captain take the precaution of being in control at the time?
Why would he do that, since the technology in which you have such great faith is in operation, and you have grave suspicions about said Captain?
You appear to have contradicted yourself, yes?
Of all the things I have faith in in the airline industry, and don't, the aircrew are the sole remaining element of the industry I haven't tossed up my hands and given up on. (Aside: Just in case you are unaware, it is my opinion that the airline industry has gone a very long way down the highway to hell (both on the commercial side and on the governmental side) and the air travel experience is being destroyed, one little bit at a time, by people who know no more of flying than they do of fornication ... to badly paraphrase General Patton. I am not of the industry, my flying and instructing (and mishap investigation) was undertaken as a military pilot. My experience as passenger had steadily degraded over time, to the point that I have in place a personal boycott of the industry unless I absolutely have no choice but to travel by air).
But back on topic of why the crew duties on long haul missions are broken up into pieces, the most dangerous elements of flying are the TAKEOFF / Departure phase, and Approach/LANDING phase, both of which you can call the
terminal phases of flight. (Being at each end of a route). The enroute phases are statistically less dangerous. Check the history of fatal accidents if you doubt me. More of them happen during takeoff and landing.
EDIT for a correction: That would include "departure" and "approach" phase, which accounts for such things as bird strikes and midairs ...
Pilots know this, and so, dear sir, common sense dictates that the Captain must be alert for the most dangerous phases of flight, and on a very long haul route, like Rio to Paris, having him in crew rest during some of the cruise portion of the flight is a common, and effective, habit pattern used by numerous airline companies with generally good results. (A similar habit pattern is/was used by US Navy P-3 crews on long (8-14 hour) patrol missions).
For PJ2:
I am unsettled by your exposition on how weather radar training is sparse at best. For the modern all weather passenger liner, that radar is an important piece of kit that allows the aircrew to make critical safety of flight decisions en route, particularly when conditions change from "what we got in the weather brief" to "look at the size of that cell!
"
However, I think this particular detail was raised in the earlier threads, and I'll leave elaboration on that discussion there. Your concise summarization and recapitulation is appreciated.
