Unbroken (25 player)

Just soloed this (without hard mode). It's very tedious. I don't recommend trying this achievement on hard mode (Orbit-uary (10 player)) if you are alone, because you need to succeed on your first attempt, and soloing hard mode is likely to require quite a few attempts before getting it right. The following strategy took me about an hour and a half to complete. I failed yesterday (tried using only one demolisher) and practiced a little. Got it on my first try today (obviously...). I am a discipline priest with Item Level 484.

You need to defeat [npc=33113] on your first attempt without using RX-214 Repair-o-matic Stations, those big iron rings with the blue light on the sides before entering the boss encounter area (Formation Grounds). Walking over them activates them, instantly repairing your vehicle, so make sure you stay away from them. The small iron rings are harmless (they are inactive teleporters). You or your vehicles may die and you can still get the achievement as long as you kill [npc=33113] on the very first try.

1. 
   
2. Clear gauntlet event (Iron Concourse).
   
   1. 
      
   2. Equip your best Item Level gear. Vehicles scale with Item Level.
   3. 
      
   4. Talk to [npc=33579] to initiate the event. The purple shield around Expedition Base Camp will go down. DO NOT TALK TO [npc=33686] (this activates hard mode).
   5. 
      
   6. Get into a [npc=33060], driver's seat.
   7. 
      
   8. Get into shooting range of the first set of Storm Beacons. Switch to passenger's seat ([npc=33067]). Use [spell=62358] (1) on the Storm Beacons until they are destroyed. Kill enemies before they reach you with the same attack. The better your aim, the more damage you will deal.
   9. 
      
   10. Switch back to driver's seat, get into shooting range of the next set of Storm Beacons. Destroy them in the same manner as 1.3. Repeat until all Storm Beacons are down.
   11. 
       
   12. Kill any [npc=34161] (helicopters) on sight with [spell=62359] (2). They come in packs of five.
   13. 
       
   14. Make sure you have killed the closest two [npc=34164] (spider machines) before proceeding. These are likely to destroy your [npc=33060].
   15. 
       
   16. Clear the Formation Grounds (boss encounter area) save for one [npc=34105]. Otherwise, you will trigger the beginning of the encounter and are sure to fail.
   17. 
       
   18. If your [npc=33060] is at any time destroyed, run back to Expedition Base Camp to get a new one.
   19. 
       
   
   
3. 
   
4. Get all five [npc=33109]s in position.
   
   1. 
      
   2. Get into a fresh [npc=33109], driver's seat. Drive it to the Iron Concourse at the end of Expedition Base Camp (down the ramp). Get out of your vehicle.
   3. 
      
   4. Go back and repeat 2.1. Position the new [npc=33109] in front of the frontmost [npc=33109]. Repeat until all five [npc=33109]s form a single file.
   5. 
      
   6. Get into the vehicle which is last in line and position it in front of the one which is first in line. Repeat until you get all five [npc=33109]s inside Formation Grounds without pulling the [npc=34105] you spared in 1.7.
   7. 
      
   8. Whenever you get close to a pack of [npc=34161]s (these tend to respawn pretty fast until you wear out their supply), hop into [npc=33167] (passenger's seat) of the vehicle you are driving and destroy the helicopters with [spell=64979] (1). Two packs of helicopters will come to you from either side near the middle and at the end of the Iron Concourse. Proceed.
   9. 
      
   10. Position all five [npc=33109]s along the southern edge of the Formation Grounds with a little space between each one. You want them close enough to be able to run quickly from one to the other but far enough so that the boss can't get in melee range of any two at the same time.
   11. 
       
   
   
5. 
   
6. Trigger the encounter.
   
   1. 
      
   2. Get into the rightmost [npc=33109], driver's seat.
   3. 
      
   4. Shoot [spell=62306] (3) at the remaining [npc=34105] until it dies.
   5. 
      
   6. Pull back a ways while [npc=33113] appears. The encounter starts as soon as he enters Formation Grounds. Soon, light barriers will enclose you in Formation Grounds.
   7. 
      
7. 
   
8. Defeat [npc=33113].
   
   1. 
      
   2. Shoot [spell=68605] (2) at [npc=33113] until your pyrite reserve is depleted. Each [npc=33109] starts with 50 units of pyrite; every shot uses up 5 units of pyrite. You must therefore shoot 10 times. By the time you shoot your 8th load, [npc=33113] should be on top of you and will soon make quick work of your vehicle. You can backpedal while shooting if you like, though this is not necessary.
   3. 
      
   4. Get out of your [npc=33109] if by now [npc=33113] hasn't broken it. Pop speed and movement cooldowns as well as defensive spells and move to the next [npc=33109] to your left. Get inside, driver's seat.
   5. 
      
   6. Repeat 4.1 and 4.2, moving away from the boss if he is too dangerously close before you get to shoot 10 times.
   7. 
      
   8. If you can help it, don't leave your vehicle while [npc=33113] is channeling his [spell=62396].
   9. 
      
   10. [spell=68605] is a stacking DoT. You can slowly stack it up with your last [npc=33109] so as not to waste any ticks if you think [npc=33113] might survive, running away from him in between shots. You might need to do so if the boss happens to destroy two or more [npc=33109]s full of unused pyrite.
   11. 
       
   12. [npc=33113] should die by the time you deplete your fourth pyrite batch.

You can now enjoy the fact that you've earned a very tedious achievement on your own and brag to all your friends about the time you've wasted doing something boring. You will sound like a very patient person. If you fail, practice the encounter solo so you get it right the week after (tweaking the spacing between vehicles, not dying in between vehicle switches...) but really it's quite easy. You won't have to do 1 through 2.4 because, if you wipe once, all the vehicles just respawn right before Formation Grounds.

There are tons of ways to do this, I just wanted to share my way. Sharing also justifies the hour and a half I spent thinking this up and doing it, plus the time lost wiping yesterday... You need to do the annoying single file positioning thing because vehicles despawn if left alone for some time. I don't know how much time that takes though. I also don't know if you can reset the encounter without spoiling the achievement (understandably I didn't play around with that hypothesis).

Have fun :)

Syriane

After passing the gauntlet, the raid has the opportunity to repair their siege vehicles to full health before engaging the Flame Leviathan himself. This achievement forces the entire raid to ignore that option and succeed on the first try.

Minimizing damage taken during the gauntlet and maximizing iLvl of equiped gear (which increases the vehicles' health) will allow the raid to begin the fight with as much health as possible. Decreasing damage during the encounter, by not activating any Defence Systems and interrupting all Flame Vents, will further increase the life expectancy of the vehicles.

Exploit (patch 3.1):
Allow your Vehicles to be destroyed after clearing the gauntlet and retrieve your ful health respawned vehicles at the start of the instance.

My guild got this yesterday. I want to clarify that you do NOT need everyone to survive the encounter, you merely need to not repair and kill him on the first try.

We had five alive at the end and the whole raid got the achievement.

I *strongly* recommend beginning the encounter by talking to Brann instead of Norgannon if you are going to attempt this, and make a straight shot for FL. Watch out for the helicopter mobs, they will cause a ton of damage on your way there, and for this achievement you cannot afford that.

Good luck!