Sometimes I think these guys just like to show off. When they launch they have the capability to go in just about any direction they choose. This particular one decided that a dive toward the ground was the way to go. It leisurely pushed off, but then tucked its wings back and down it went, spreading them at the last moment about 10 feet off the deck and then heading off at a fast clip.
Average flight speed for a Bald Eagle when just cruising around is about 30 mph. However, when diving they can reach speeds up to 100 mph!