EMPLOYER: Dom
PREREQUISITES: MM #47 (Predator), Must be Franklin
REWARDS/UNLOCKS: Parachuting Unlocked
COMPLETION REQS:
1. Free Faller: Fall for 7 seconds before opening the parachute.
2. Big Air: Get 2 seconds of air during the bicycle race.
3. Downhill King: Win the bicycle race against Dom.
After the "Predator" mission, head to northwest Vinewood Hills to find this ? icon on your map. There you will meet... a dog? The dialog here is some of the best in the game (seriously... so good), so enjoy while you follow the dog to a man tangled up in a tree.
After having your mind blown (was it there or not!?), you will meet Dom, an adrenaline junkie. After freeing him he will talk Franklin into joining him in his helicopter. Get in and you'll notice you can skip the ride if you wish. The dialog here is good, but it does stop after awhile so skip the ride once all the talking is done. At the end you get to jump from the chopper.
Be sure to stay in free fall for more than 7 seconds for one of the mission's medals, then aim for the landing zone on top of the mountain (Using L1 and R1 together makes aiming for a landing much easier. Be sure to circle around a bit if you didn't drop long enough).
Once you hit the ground you'll have to run to some nearby bikes and a race against Dom down the mountain starts. Like any race you want to go from checkpoint to checkpoint. Many of these checkpoints have jumps on them and a few even have gaps in the jumps so keep your speed up and try to aim the camera downhill so you can see the terrain coming up. It's a good idea (at least on an initial play-through) to let Dom get ahead of you so you can use his example in navigating the jumps, although one of the mission medals is to beat him in the race. You can pass him near the end if you wish.
Once you are done Dom will be added as a contact for future extreme sports and parachuting as a hobby will now be unlocked. Extreme!