Skate 3

Done easily at the Super Ultra Mega Park using this method. If you want to keep track of your float time, pause and go over to game settings, controls, and turn on Hall of Meat mode.

This achievement requires you to to find a place to get enough hangtime to Spread Eagle for 10 seconds. The obvious place to go is the Super-Ultra Mega-Park, but the route isn't so obvious. Let me spell it out for you:

When you spawn at the park, turn around. Go up the road until you get to a bridge. Head left, jump the barrier and get on the rock formation. I highly advise you make a session marker here because this will take a few tries to get down. Look to your left and you will see various levels to jump off. I advise you go to the highest point to give yourself the best chance.

Now sprint, trigger a bail and hold down on the right stick. As soon as the clock in the bottom left goes over 10.00, ding!

If need be, I can make a video tutorial for this as well to tell you how to get there and go about it.
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Did I miss anything? If so, tell me in the comments.

Adding to iAmCyberwaste's great description and all videos above.

For me just reading 'Super-Ultra Mega-Park' did not make it clear where this park was. This was after hours of playing a few days ago when I got 23 Achievements for Skate 3 in one day.

So I think for people who are just checking out these tips, it is important to have it completely clear how to get there.

1. While in-game, go to the Pause menu
2. Select Free Play
3. Select Challenge Map
4. Select University Districy
5. Select Super-Ultra Mega-Park

Then follow iAmCyberwaste's great description and you can unlock the Achievement.

Just go to the Super Mega Ultra Park and follow the video. TIP: you can also score 10,000 points and 75,000 bail points here if you land it.