Weekend closures of the I-90 floating bridges during Blue Angels aerobatic flights are required, as state Department of Transportation and Seafair officials make clear, to prevent accidents on the bridges and in the air: They are “complying with Federal Aviation Administration rules to create a safer environment for drivers and Blue Angels pilots by reducing distractions to both.” Car crashes are the greater risk should drivers try to catch a glimpse of the Navy jet pilots performing wing-to-wing swoops, rolls and planned near-hits at thundering speeds. But plane crashes are both a lure and a reality of the usually death-defying Angels performance. The Navy in fact keeps tabs of the accident history of the Angels – 54 mishaps since 1946. They include fatal stalls, aerial collisions and bailout crashes – a handful of pilots ejected safely before their planes hit earth. According to the Angels’ memorial page, altogether 26 pilots have died, most in air shows (several who were killed in combat are included in the tally).The roster dates back to the death of Lt. Robby Robinson after a wingtip broke off his Bearcat during an aerial dive in 1946. The Navy history doesn’t list the total of those, including civilians, injured or dead on the ground. But in the last crash in 2007, killing Lt. Cmdr. Kevin Davis when his F/A 18 Hornet went down in a residential area in Beaufort, S.C., eight on the ground were injured and several homes damaged.That crash was blamed on an unusual pilot error – Davis, who flew here in the 2006 Seafair air show – became disoriented after failing to properly tense his abdominal muscles. During a high-speed maneuver, that tensing is required to counter the gravitational forces and keep a clear head.The 2007 crash prompted the FAA to take a long look before finally approving the Angels reappearance that year over Lake Washington – where the Angels fly in an imaginary aerobatic “box,” a safety zone approximately two miles long, 3,000 feet wide. Most maneuvers are done over water rather than residential areas. Some worried about a repeat of the 1993 incident here when the pilot of of an Angels Hornet went into an unplanned near-stall, but recovered. The next year the FAA ordered the Angels to remove some of their more risky maneuvers from the show. In response, the Navy boycotted Seafair for two years, returning in 1996 but flying over Elliott Bay instead. Next year they returned to the lake. The Angels’ spokespersons – and informational material – stress that “Safety is paramount for every demonstration,” in the air and on the ground. They take risks but not unnecessary ones. Seattle doesn’t seem to doubt that, as it gathers below to watch devoutly on Thunderboat Sunday. The blue jets are loud, low, fast and dangerous. That’s what makes it a show.