You are in a Helicopter

A helicopter was flying around above Seattle yesterday when an
electrical malfunction disabled all of aircraft's electronic
navigation and communication equipment. Due to the clouds and haze the
pilot could not determine hisposition or course to steer to the
airport. The pilot saw a tall building, flew toward it, circled, drew
a handwrittedsign and held it in the helicopter's window. The sign
said "WHERE AM I "? in large letters. People in the tall building
quickly responded to the aircraft, drew a largesign an held it in a
building window. The sign said, "YOU ARE IN AHELICOPTER ". The pilot
smiled, waved, looked at his map and determined the course to steerto
SEATAC ( Seattle/Tacoma) airport and landed safely. After they were on
the ground, the co-pilot asked the pilot how the "YOU AREIN A
HELICOPTER " sign helped determine their position. The pilot
responded, "I knew that had to be the Microsoft building because they
gave me atechnically correct but completely useless answer ".