My Love-Hate Relationship With The Oxygen Mask
The crew oxygen mask is like a parachute in the fighters I used to fly: you don’t give it a lot of thought, and you never need it until you really need it. Then your life depends on it.
Regulations require that if one pilot leaves the flight deck when flying above FL250, the other pilot must wear and use the oxygen mask. That makes a lot of sense, since the Time of Useful Consciousness (TUC) at altitude is less than 30 seconds. We don’t want the one remaining pilot at the controls flailing around trying to find the mask when it’s needed. It needs to be on and in use, so there is no potential for the only pilot in the flight deck becoming incapacitated.
That makes perfect sense, but, unfortunately, it’s not always followed. In fact, with some quick-donning (can be donned with one hand in less than 5 seconds) masks, crewmembers are not even required to check the fit and operation of the mask before flight. Your flight manual will provide guidance.
So there I was (picture me shooting down my watch with the other hand) at FL350 over the Yellow Sea at the controls of my airline’s B777, June 23, 2004. The date is seared into my mind. My copilot needed to use the lavatory. I called the flight attendant up to the cockpit (in accordance with my airline’s procedures) and donned the quick-donning oxygen mask. I kept it on until he returned to his seat.
After I removed the mask, my faced had a dirty, itchy feeling. Apparently, there had been a lot of dust in the mask, even though I had blown it out to clear it of dust before I donned it. When I got back to my hotel in Narita (near Tokyo), I went for my usual run, along my usual route. I had been in training for an upcoming race, and had been making great progress. In fact, I had been cutting more than 5 seconds from my run every time. But this time, I couldn’t even complete the run. I was totally out of breath.
When I got home, I had the same problem when I tried my usual runs. When I pushed myself on the treadmill, I started getting chest pains. Not good. So I went to see my family doctor, and he sent me to see a pulmonologist, who administered a wide range of tests.
“Sorry to tell you this,” the doctor said, “but you have asthma. You caught it from the dust in your mask.”
“You can’t catch asthma,” I protested.
“You better tell that to all the people who caught it from the smoke following the Hayden fire.”
“Well,” I asked, “how long will I have it?”
“Just the rest of your life.”
So, I now have asthma (not too bad, mostly triggered by exercise). And I didn’t enter the race. But I think back to how I used to have my own oxygen mask when I flew in the Air Force, a mask I kept scrupulously clean. And in the airline environment, I just got whatever mask that was in the cockpit. I was not a happy camper.
To answer your unasked question: yes, I continued to don and wear the oxygen mask when the other pilot left the flight deck, because it’s required by regulations. But I always went to extra efforts to make sure it was squeaky clean, though.