Airship Guide

[Nyalia]

Does just visiting the sector by itself do anything or do you need to visit it first then another sector or something?

It's pure RNG. As far as we can tell, nothing affects it, at least not enough to be clear. Just visit that sector every trip, and eventually you'll get it. The only way I know of to speed up discovery is to put your best rigging and worst aftcastle on the ship (maximizing speed) and hit just that sector over and over. That'll give you the most chances for discovery. But, you'll be giving up loot by doing that, as your retrieval will be terrible and you will only be hitting one sector. It's an extremely inefficient use of fuel and time though.

So, you have two options:

1. You can either hit that sector while hitting other sectors that you actually want to visit. I recommend this option. This gets you normal amounts of loot and doesn't slow down your gathering efforts, especially since sector 17 has good materia in it (grade III/IV crafter materia). You'll hit 17 once every ~60 hour trip. If you like Gatherer Materia, I recommend SC16 -> SC17 (68 Range), SC10 -> SC16 -> SC17 (80 Range), SC16 -> SC17 -> SC22 (93 Range), or SC10 -> SC16 -> SC17 -> SC22 (105 Range). If you like Crafter Materia far more, I recommend SC13 -> SC17 (82 Range) or SC07 -> SC17 -> SC13 (98 Range). The shortest of those would take about 50 hours, the longest would take about 80 hours. Speaking personally, SC17 is the sector I hit the most because it drops the best materia. All three of my rank 50 ships hit that sector every trip.
2. You can hit just that sector in the fastest ship you can make (bronco aftcastle, best rigging you can make). With Odyssey rigging, that's one chance at discovery every 30.5 hours. With Tatanora rigging, that's one chance every 28.5 hours. You'll probably get almost no loot from it though.

So, up to you - normal loot from three sectors, or no loot but double the chances of discovery over time? You can also meet somewhere in the middle - hit just SC17 (or SC16->SC17) with good rigging and a moderate aftcastle, having a trip time of about 36 hours (closer to 48 if you hit SC16 too for gathering materia and far eastern coins) and a much better chance at getting some loot.