What Happens When You Step On the Brakes in a 747? In short: the brakes heat up to 2,500 degrees, and the tires immediately deflate to keep from exploding. Then the brakes burn. By Whet Moser May 19, 2011, 2:33 pm Via Gizmodo, an amazing video of a Boeing 747-8, carrying 975,000 pounds of cargo, being brought up to 200 miles an hour before the pilot steps on the brakes. The plane just took its first flight in March.