When playing The Legend of Zelda: Skyward Sword HD, you will eventually be tasked with finding the windmill propeller that fell under the clouds. For the people of Skyloft, such a thing happening basically means the dropped item is gone forever, but that's not much of a problem for you thanks to the tablets' pillars of light. But before you run off trying to find that fallen item, you'll need to do a bit of prep work first. As you have no way to bring it back to heaven, even if you find it.
How to find the windmill propeller
After being tasked with finding the windmill propeller, the first thing you need to do is find a way to bring it back to the sky after you find it. Fortunately, Gonzo can help you, because his family owns a robot that traveled under the clouds. Go talk to him and you'll find out that the robot needs repairs and he'll need an ancient flower to get him back up and running. If you don't already have them, they're fairly easy to find in the Lanayru region around the Timeshift Stones. So give it one and the robot will be ready to go in no time.
Now is the time to search for the helix itself, which you can do by dowsing, but it may take some time. Luckily, the propeller is actually in a place you've been to before, in fact, you might even remember seeing it before. You'll need to fly over the pillar of red light and drop down into the Eldin area, specifically at the entrance to the dungeon. Go to the left of the dungeon entrance and head towards the tower you had to blow up to dig up a key piece below. Right next to the ruins of this tower is the helix. Simply summon Fi to your side and have the robot pick it up for you, then all you have to do is fly back up into the sky to finish delivering it.
The Legend of Zelda: Skyward Sword HD is available now on Nintendo Switch