On April 15, 1999, a South Korean cargo plane crashed due to a confusion over units. The plane was to fly from Shanghai, China, to Seoul, Korea. After takeoff plane climbed to 900 m. Then the first officer was instructed by the Shanghai tower to climb to 1500 m and maintain that altitude. The captain. after reaching 1450 m. twice asked the first officer at what altitude they should fly. He was twice told incorrectly they were to be at 1500 ft. The captain pushed the control column quickly forward and started a steep descent. The plane could not recover from the dive and crashed. How much above the correct altitude did the captain think they were when he started his rapid descent and lost control? (It turns out that aircraft altitudes are given in feet throughout the world except in Chine, Mongolia, and the former Soviet states where meters are used.)