Egyptair always contested the NTSB conclusions. The Egyptian pilots association asked help from the ALPA investigation department too late. But what was revealed was that one of the right hand elevator servo actuators went hard over. As there are 3 actuators per elevator side, one of the retaining pins on the servo going hardover would shear as it is fighting against the other 2 servo actuators, and in this case, noting would be noticed until scheduled maintenance. Egyptair claims that one servo actuator had already gone hardover and sheared on a previous flight, leaving 2 servo actuators remaining. During the event with Batouti at the controls, it would have been the second one failing. In this case, it is not 1 against 2 but 1 against 1 shear pin, and it would be a 50/50 chance of the failed one to shear. In this case, they claim that the GOOD remaining one sheard, leaving the one that had gone hardover to push the elevator full down. Boeing issued later a service bulletin requiring inspection of the 767 elevator servo actuators and their shear pins within 400 hours of flight time; but that was not publicized by NTSB.
Batouti was eating his meal during that time, alone in the cockpit, and it didn't make sense for him to suddenly just quit eating, place his tray over his flight bag and commit suicide. The autopilot disconnected itself because of the force generated by the hardover actuator itself, and not because of a control input from Batouti. He knew he was in trouble, and the pucker factor made him only say one thing: 'I put my faith in God'. The NTSB translator was Lebanese, who interpreted this as being a fanatic expression. However, it's a commonly used expression in Egypt, even by non muslims such as Christians and even Jews.
As they pitched down, Batouti would have been fighting against the downward pitch, pulling back with all his might. But he would not be able to override the servo actuator, powered by 3000 PSI of hydraulic pressure. What would appear as him pushing forward would have been really him trying to pull back. The captain pulled hard enough to split the elevator. But it split suddenly and he over G'ed the aircraft as it was going supersonic, causing its breakup on the pullup.
As the aircraft went past its Mmo (maximum Mach number, and if I remember correctly on the 767, it's .86) and nearing transonic flight, the engines would have flamed out due to compressor stall. They are not designed to keep operating in that range. In any case, when you're in a screaming dive, you pull back on the throttles. Batouti at that point would have let go of the controls in order to restart the engines after a double flameout. That procedure is to close the throttles and turn the engine/ignition switches to off and back on again to Ignition and hope for an airstart.
In a number of instances, the NTSB have been quick to blame the pilots based on circumstatial evidence, in order to end expensive further investigations. They have been successfully challenged in the past.
Yes, EgyptAir has contested them. And the ECAA findings are pretty sketchy. They detail a lot of "possible" explanations with no facts. Let's take the scenario you propose which does nothing to explain why Batouti didn't say a WORD to the captain about what was going on or what he was doing... but let's look at it anyway.
An elevator hardover's and that caused the crash. Fine. How would that scenario play out? First, the elevator would move, abruptly and hard. The aircraft would pitch down VIOLENTLY. The autopilot deals with this all the time in turbulence. It would attempt to correct by pitching the elevator up. A failed response would then cause the autopilot to disconnect and alarm. That's absolutely correct. Here's why that theory fails.
1) The autopilot was diconnected before any nose-over maneuver began. Is this a magic autopilot that can predict the future, that a servo is going to fail, and disconnects before the elevator hardovers?
2) The throttle was reduced to idle before the dive began. So now we have not just a magic auto-pilot, but a magic Batouti that can predict a hard-over is coming. Already the ECAA hardover theory is shot to hell.
3) Why didn't Batouti say anything? Sitting there in silence is the worst thing you can do in an emergency and this would be the first recorded case of flight crew refusing to answer his captain's questions during an emergency.
4) Why did this magical hardover only affect Batouti's control column? The FDR shows a split condition with the co-pilot pushing forward and pilot pulling back. In your scenario, both would be fighting the same forces. But the FDR doesn't show that.
5) You acknowledge Batouti was the likely the one that turned selected engine cut-off. Let's look at that separately.
5a) You're in a screaming dive, you want to retard engine power completely, you select idle. Makes sense I agree. 1 point here. Oh wait, except engines were idled before the dive. Take that point away.
5b) If you're in a screaming dive, with a ton of excessive velocity that you can trade for altitude when you recover, why would you stop trying to arrest the uncontrollable dive to restart the engines?
5c) If you're resetting the engines because you're a moron and decide that an engine restart when you don't need or want engine power is more important than overcoming the dive, why don't you say "Restart" when the captain asks why you turned them off?
5d) The procedure for engine restart isn't "Cut-off then do nothing". It's ENG START switches - FLT, THRUST LEVERS both - IDLE, FUEL CONTROL - CUT-OFF then RUN. Why didn't Batouti set the start switches to FLT? Why didn't he turn the fuel control back to run after cut-off? His actions are inconsistent with an air restart.
5e) Why did Batouti, assuming you're correct, attempt to restart engines that, according to all indications, was functioning normally in the midst of an uncontrolled dive? Regaining elevator control, if it had indeed been lost, would've been the priority, not restarting engines that he had no intention or need to use while still plummeting towards the ocean.
6) Let's talk about compressor stall shall we.
6a) Compressor surges are almost universally accompanied by a very loud bang, loud enough that it would have been recorded on a CVR. The lack of a bang isn't enough to say there was no stall, but without it, I wonder what caused Batouti to decide to stop focusing on recovering from the dive and start worrying about engines.
6b) If you're near or beyond Mmo or Vmo and you have a compressor surge, first instinct is that the cause was excessive speed. In other words, there's no point in attempting a restart while pressure will continue to exceed tolerance. All you'll be doing is restart after restart as the compressors continue to stall out. In fact, you risk doing more damage by attempting a restart than by just leaving the engine out. The more critical of the two conditions - compressor stall and exceeding Vmo/Mmo - is the speed. You MUST reduce your speed. That is the priority. Fuck the engines. A plane can fly without engines. It can't fly if it gets ripped apart from excessive speed and it certainly can't fly underwater so fix the dive first, then worry about the engines.
The ECAA report never explained any of these. At all. Not even a little. That's a lot of unanswered questions about Batouti's behaviour that are not only "odd", they're downright damning, and only 1 thing that makes sense until you realize it was done at a time that doesn't make sense. There is literally no rational explanation for why he did those things. So the answer, by logical deduction, is that the explanation must be irrational. Why would a pilot do things irrationally and intentionally that lead to their own death? Suicide is up there. And one could argue that any other possibility, terrorism, to get even with someone on the flight, to punish the company, etc etc, even duress, is still suicide in addition to those other things.
You also have to remember that the ECAA didn't say "Here's the cause!" They said "Here are a few possible causes. None of which explain Batouti's behaviour which was irrational, but they are all possible causes. Oh and by the way, please don't look to closely and realize that every single one of these possible causes is directly refuted by evidence recovered from the CVR, FDR and wreckage."