In "The Empire Strikes Back", the Walker's heavy armor was unaffected by the blasts of any rebel weapons, canons, and snow speeders, yet the legs of these enormous all-terrain monsters could not brake through some tiny tow-cable and tripped and fell? Then after they did fall, the snow speeders would fly by with a few blasts and destroy the Walkers. So how did the impenetrable armor of these Walkers all of a sudden become penetrable just because the Walkers were down on the ground? How was Luke able to cut open the Walker's hatch underneath with just a light saber? So light sabers and thin cable can destroy a Walker, but heavy laser blasts cannot? Someone needs to redesign these AT-ATs. I know it is just a movie, but just a thought I had.
Luke hits something, causing the hatch to shoot open - rather than actually cutting straight through it. The shots hit the AT-AT's neck when it was on the ground, rather than the hull.
This was disucssed recently in another thread....which of course I can't locate. So I'll go with what iron lord said
I think I got the "hatch opened rather than was cut open" from another thread, and "weak neck armour" from this thread: http://boards.theforce.net/threads/how-did-the-snowspeeder-blow-up-the-at-at.50026103/
As a matter of fact the original scene design had snowtroopers disembarking from the fallen snow walker with the Rebel troops rushing forward to meet them while they had the advantage of the moment (and originally the other walker's head exploded because Hobbie had decided to take the lead walker out with his last breath...) I don't buy into the neck theory, because Luke would then have probably suggested to concentrate the snowspeeder fire, there. "That armor is too strong for blasters" seems to suggest merely a physical protection, but frankly I'd find it odd if all kinds of old starfighters like the X- and Y-Wing feature deflector shields but vehicles shouldn't? IMHO, "armor" can include both mechanical and energy shield protection. When that particular walker fell, the fall also knocked out its deflector shield, but the Rebels didn't know that, until two snowspeeders "tested" it (had the deflector shield not been taken out, the advanvcing Rebel troopers would have taken care of the disembarking snowtrooper survivors)
Just after 1:48 the two shots occur. Neither hits the neck. One hits very slightly below, the other just slightly above. The thing fell, was damaged enough that the armor was not as effective, and like any vehicle probably blew up from the inside thanks to the blasters hitting something important.
In my headcanon, when the walker fell it's armor buckled and cracked slightly, just enough to weaken it right before the snowspeeder opened fire.
The Rebels may have modified their weaponry in order to penetrate the armoury of the AT-AT Walkers. Up to that point they were getting know where but certain points of the casing of the steel may have been detected as particularly vulnerable to laser fire.
getting close and hitting the neck at the right angle can destroy them, but its impossible to get that close to a fully functioning one, you see a speeder try and get shot down, but once they are downed the speeders can hit the sweet spot.
Which sweet spot? To me it looks once the walker had fallen its vulnerable parts were better protected than before...
Given the slow speed the walkers were advancing, I really wonder whether that truly constitutes a crucial difference.
I think this makes the most sense. The head hit the ground with considerable force, and obviously the neck wouldn't be designed to withstand pressure like that, so the armour around that area (as opposed to the neck being the Achilles' heel) would have been compromised.
If anything, the neck itself is actually harder to hit in that crumpled position. This explanation makes the most sense to me. If it were possible for a single well-placed laser blast to fully explode a functioning walker like that, Rogue Squadron wouldn't have been messing around with the harpoons and tow-cables.
That explanation works too...maybe combine the two theories. The shields were down and the sweet spot could be accessed.
If you look the neck of the walker is what is shot. It is a vulnerability. Also the leg joints are lightly if not armored at all. This is presented in the new book Lost Stars where one of the pilots at Echo Base knew the vulnerability because he had learned the schematics at the Imperial Academy.
This is a good example of EU, i.e. the author has watched the Battle of Hoth and noticed that a lot of Rebel shots aim at the leg joints, so there must be a good reason for that.
When the walker is upright on its legs, it dampens enemy fire throughout the body via a sophisticated dampening system running from the body to the legs and onto the feet making it nearly impossible for that type of fire to penetrate it. When the walker is on the ground, that system is rendered inert. And that's a buncha malarkey that I just made up, but made you think about it for a second.
Something I just remembered yesterday: In ANH General Dodonna told the pilots that the Death Star's thermal exhaust port was "ray shielded", so they'd have to use proton torpedoes. So there was a technology somewhat different from deflector shields (which also protect against torpedoes). Apparently the snow walkers (Joe Johnston hates "AT-AT") were "ray shielded", too.
