Chuck Yeager: I never lost a pilot while flying chase, but there were many close calls. After I had flown the X-4 research airplane, the Air Force turned it over to NACA, and I flew chase for their pilot. Joe Walker. We were climbing together through 20,000 feet, and was listening to Joe talking with the control center when it hit me that there was something very wrong. Joe wasn’t making sense, and he was slurring his words. Hey, I thought, that guy has hypoxia. And it was going to getworse, because we were climbing straight up. Without enough oxygen pilots act drunk and irrational, then black out. I flew close to his canopy and saw that his head wasn’t rolling from side to side, which probably meant he was getting partial oxygen from his mask. I radioed: “Hey, Joe, be alert. Go to one hundred percent on your oxygen.” He replied, “Oh, shut up, will you. I’m trying to fly a program here.”
I needed to find a way to slap him back to reality. I said, “Hey, man, I just flamed out. Got me a real emergency. Follow me down.” That got through to him, and he went down with me, his head clearing at the lower altitude, although he was dazed. Being typical NACA-arrogant, he was ready to readjust his oxygen mask and go back up. “No way,” I said. “Get down on the ground.” He finally did.