I was listening to air traffic control / pilot exchanges on YouTube when I came across this news story from 2013. (The story also includes some of the ATC exchange).
A pilot started slurring when speaking to the air traffic controller. She began encouraging him to descent and to put on an oxygen mask. Another pilot was on the channel too, pipping in.
It turns out the pilot was suffering from a lack of oxygen, or hypoxia. The problem with hypoxia is that you don’t usually realize it is happening to you. The higher in altitude you are, the faster you will pass out from the lack of oxygen. Fortunately for the pilot, he was low enough in the sky to buy himself some time–enough time to get the warning from ATC to use the oxygen.
After watching the video, I looked up the incident for more information.
“Five zero one papa mike,” came the call over the radio. It was the pilot. She could understand him. Checking the numbers on the screen, it showed he was at 26,800 feet. He had descended.
“Yes we are, thanks for the help,” he said. “For some reason the cabin altitude was showing okay but it uh we had some oxygen issues so, down to uh 18 or lowest we can get.”
He still wasn’t OK, confusing altitudes, and repeating instructions, but as he continued to descend he became more and more coherent.
Last week the National Air Traffic Controllers Association honored Hollingsworth with its Medal of Safety award. She was one of 12 controllers credited with a remarkable save. It was humbling she said, a big honor.
The plane was a Piaggio P180 Avanti, which seats 9 people. The whole transcript of the exchange is here.
Here’s the original news report I came across:
For a better look at what the experience is like, here is a video of someone who induced hypoxia.
Some pilots go through a similar training to help them identify the signs of hypoxia.
I could feel my mind going deeper and deeper into a fog. No matter how hard I tried to focus, I couldn’t seem to make sense of the basic problems that I had been tasked with. What is the sum of 15 plus 4? The question wasn’t hard, but it took all of my brainpower to muster up the answer. 19. Next question … I felt generally OK, but there was pressure behind my eyes, I could feel a slight headache coming on and my vision didn’t seem quite right. With the exception of the sheet of paper in front of me, the remainder of the room had faded away. It was time to don the oxygen mask.
This sort of training can help pilots learn when they should put on their oxygen mask–before it is too late.
According to that article:
A query in the National Transportation Safety Board’s aviation accident database found 24 accidents related to hypoxia in the past decade. Twenty-two of them included fatalities.