A helicopter was flying in the Seattle area when an electrical malfunction disabled all of the aircraft's electronic navigation and communications equipment.  Due to the clouds and haze, the pilot could not determine the helicopter's position and course to get to the airport.

The pilot saw a tall building, flew toward it, circled, drew a handwritten sign, and held it in the helicopter's window.  The pilot's sign said, "WHERE AM I?" in large letters.

People in the tall building quickly responded to the aircraft, drew a large sign, and held it in a building window.   Their sign read, "IN A HELICOPTER."  The pilot smiled, waved, looked at his map, determined the course to the airport, and landed safely.

When the co-pilot asked how the sign helped determine their position, the pilot responded, "I knew that had to be the Microsoft building because they gave me a technically correct -- but completely useless -- answer."