From a New York Times obit by Clay Risen headlined “Viktor Belenko, Who Defected to the West in a Jet Fighter, Dies at 76”:

On a clear late summer day in 1976, a plane popped up on the radar just off the coast of the northern Japanese island of Hokkaido. It had been flying a mere 100 feet off the water, low enough to avoid detection. Now, suddenly, it climbed up to 20,000 feet. Clearly, the pilot wanted to be seen.