Flight over this area was strictly prohibited, but this was not enforced in any significant way at the time; surface-to-air missiles were not installed around Washington until after the September 11 attacks. Preston spent 5–6 minutes hovering a couple of feet above the Washington Monument's grounds, then flew over the Capitol, and went on to follow Pennsylvania Avenue to the White House.[1][2] The Secret Service policy, at the time, was to fire at aerial intruders, but when to do so was left vague—especially if it could harm bystanders. While Preston was hovering above and briefly touched down on the South Lawn, the White House Executive Office control center watch officer, Henry S. Kulbaski, attempted to contact his superiors by phone but received no answer.