Zero Fail: The Rise and Fall of the Secret Service by Carol Leonnig:
On September 12, 1994, a very different kind of threat came at the president—in the form of a stolen red-and-white propeller plane. At about 1:45 A.M., the small two-seater Cessna flew low over the office buildings along Seventeenth Street in downtown Washington, made a U-turn when it reached the Washington Monument, and then headed straight for the South Lawn of the White House. The pilot shut off the Cessna’s power as he set a glide path, but then tried to pull the nose up slightly when he spotted a sea of metal bleachers set up on the grass for an event planned for later that afternoon.
The plane clipped a massive magnolia tree, planted when Andrew Jackson was president, and then skidded fifty feet to a stop within inches of the White House’s sandstone wall, just outside the State Dining Room. The crumpled wreckage smoldered with the dead pilot inside, just two floors below the Clintons’ bedroom. Fortunately, that night, the Clintons happened to be sleeping in the nearby Blair House while their residence’s ventilation system was being repaired.
Neither the Secret Service nor anyone else did anything to protect Crown—largely because they had no idea the plane was coming. Some officers stationed on the South Portico noticed a low-flying place over the Mall, but they had only second to scramble out of the way when it turned back toward the White House. After the fact, fire trucks swarmed the South Lawn to douse the area. Bomb detection teams carefully picked through the wreckage to see if any explosives were aboard the plan. Secret Service Deputy Guy Caputo work up senior agency leaders at home to alert them to the close call. A detail agent work Clinton to inform him of the crash, and the president went back to bed.