However, the argument that the plane had to be remote controlled to account for the turn doesn't stand up. The plane obviously didn't go into a stall, but if it hand it would have been because physical factors like velocity of the aircraft and mass of the aircraft, flying conditions, and so on. Regardless of whether Hanjour flew the plane (which I firmly believe he did) or if it was remote controlled, it is still subject the the same physical factors which could have knocked the plane into a stall.
Hi Josh, your intuition is correct. Furthermore, the flight path suggests that it was not under automatic or remote control, as I will explain.
First, some background. I feel well qualified to answer this question. I work autonomy projects for NASA in real life (references available upon request), and I've led autonomous UAV efforts, though nothing that's actually piloted a plane yet. If that's not good enough for you, a member of my group left this year to go work Global Hawk, and I can forward any questions to him if needed...
Second, let me state up front that the technology
does exist to remotely or automatically pilot a jetliner into the Pentagon, with a high degree of reliability. It is theoretically possible. It is also theoretically possible for someone to have planted 2,000,000 pounds of explosives in the WTC towers... While theoretically possible, it would be enormously difficult to have piloted Flight 77 remotely or automatically.
Third, as you say, remote guidance of the aircraft would not have improved its flying characteristics or performance. Quite the opposite, in fact. An autonomous aircraft control system will stay away from the limits of performance whenever possible, simply because the autonomous control system may not be stable there -- it may not react quickly enough, may accidentally overshoot, or it may have never encountered those conditions and behave unpredictably. Similarly, a remotely controlled aircraft will avoid challenging flight regimes because the pilot suffers additional delay, and cannot completely sense what his aircraft is doing.
Think of it this way: Suppose you're driving your car. Blindfolded. Suppose a friend is in the passenger seat, telling you what to do. Would you rather drive on a flat, open parking lot, or drive along the edge of a cliff? Pretty simple decision.
Fourth, the 330 or 270 or whatever degree diving turn itself is consistent with a pilot scanning for visible landmarks and suddenly spotting his target, and not consistent with remote or autonomous systems. A pilot running remotely would not have the same visual acuity, -- looking through a camera, say -- and would absolutely have to be using other sensors (GPS, terrain-following radar, etc.) in which case he'd have the Pentagon pretty clearly marked. There would be no need for a sudden correction like that. He'd have a better flight plan from the beginning.
An autonomous system likewise would not rely upon visual landmarks. You could build an autonomous system that simply went after the Pentagon based on GPS coordinates, but this would be risky -- GPS alone does not give terribly accurate height information and the odds of clipping much more than lightpoles would be significant, not to mention you could lose GPS signal for a variety of reasons. Global Hawk, to pick one, doesn't rely on GPS for height information to land; instead, it overflies the landing strip, images and ranges it with synthetic aperture radar, then comes back and lands according to its updated measurements. Flight 77 didn't have a radar of that caliber and mounting one would be prohibitively difficult. If I wanted to try an autonomous approach, I would supplement GPS with a directional marker, perhaps an infrared laser designator trained on the Pentagon, or a coded IR beacon on the roof. The aircraft would need an additional sensor to pick this up, but it would be relatively small and could be set upon the "dashboard."
Still, in this case, there is no reason for the aircraft to execute such a big turn. Again, the turn itself indicates a sudden change in direction based on suddenly acquiring new information. No autonomous or remote system would have suddenly woken up in this fashion.
From the FDR data we saw while discussing John Doe X / Robert / weedwacker's flawed analysis, the aircraft also recorded significant last-second corrections all the way up to impact. Again, this is consistent with a pilot on board navigating by sight. It is not consistent with any automatic or remote system. If done remotely, the remote operator would have run a real risk of entering PIO (Pilot Induced Oscillation), probably crashing the plane short of its mark, and thus would have made more gentle corrections to a smoother course set further out. If an on-board autonomous system provided these control inputs, its control laws are awful and it's a wonder if it could work at all -- we should see a fairly continuous curve.
Fifth, I suppose one might argue
"of course they made it turn funny, to make you believe it was an amateur pilot." This is, of course, impossible to disprove. However, those "deceptive" maneuvers would add a great deal of unnecessary risk if the plane was remotely or robotically operated. I can't envision some shadowy group going to all that trouble, making a trick aircraft to pull off the biggest deception since New Coke, and then taking a chance like that rather than just flying it properly. Makes no sense at all.
So in conclusion, not only are you correct that the flight performance issues would apply to a remotely guided plane as well, but in fact they are even more significant, and additionally the flight path is not consistent with any remote or robotic control paradigm I've ever heard of.
And I would know. I was meeting with other scientists at Boeing Commercial in Everett, Washington when Flight 77 hit. Later that evening, we considered pitching the idea of an automated on-board failsafe pilot, activated by code from Air Traffic Control, to take over in case a flight was ever highjacked again, to the government (probably DARPA). We never did, though. Real pilots would object, and besides, soon after air travel took a big hit, and Boeing's willingness to fund new technology understandably waned for some time. We could do it. But nobody has.
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