A pilot with poor eyesight had managed to pass his periodic vision exams by memorizing the eye charts beforehand.
One year though, his doctor used a new chart that the pilot had never seen before. The pilot proceeded to recite the old chart and the doctor realized she had been tricked.
The pilot proved to be nearly as blind as a bat. The doctor couldn't contain her curiosity.
"How is it that someone with your eyesight can manage to pilot a plane at all? I mean, how for example do you taxi the plane out to the runway?" she asked.
"Well," the pilot said. "It's really not very hard. All you have to do is follow the instructions of the ground controller over the radio. And besides, the landmarks have all become quite familiar to me over the years."
"I can understand that," the doctor replied. "But what about the take-off?"
"Again, a simple procedure. I just aim the plane down the runway, go to full throttle, pull back on the stick, and off we go!" the man explained.
"But once you're aloft?" the doctor queried.
"Oh, everything's fully automated these days," the pilot said. "The flight computer knows our destination, and all I have to do is hit the autopilot and the plane pretty much flies itself."
"But I still don't see how you land!" the doctor continued.
"Oh, that's the easiest part of all. All I do is use the airport's radio beacon to get us on the proper glide path," he explained. "Then I just throttle down and wait for the co-pilot to yell, 'AIEEEEEEEEEEEEEEEE!' pull the nose up, and the plane lands just fine!"