Pilots Told To NOT Wear A Mask: Finally, A Change To The O2 Rules?

Aviation rules and regulation are being bent and flexed rapidly during the Covid-19 crisis. The irony for this rule change is that while everyone else is being asked to use a mask, pilots are being relieved of their requirement to wear one, but this is a little different.

The most recent change is to the cockpit oxygen-mask regulation and this might be a turning point to permanently change the regulation. Right now, the industry is trying to reduce the potential for pilots to be exposed to any pathogens that may be on the masks. With this emergency amendment, pilots are no longer required to don an oxygen mask between FL250-FL410 when they are the sole pilot at the controls - but for many pilots, that won’t be something new.

Brush Cobwebs Off The Rules

The Code of Federal Regulation Part 91.211 says in general that one pilot needs to be wearing an oxygen mask always above FL410 and at FL350 and above if the other pilot leaves the cockpit. Part 135.89 (let's just focus on high performance, pressurized aircraft with cabin pressure below 10,000 ft MSL and pressure-demand oxygen systems) reminds us that at least one pilot at the controls will wear an oxygen mask at FL 250 and above if the other pilot leaves the cockpit and at all times above FL 350 (your Op Specs might be even more restrictive).

Since most business jets are consistently operating much higher than that, there should be a lot more nasal sounding conversation (the Darth Vader voice via the mask) on the frequency, but there isn't.

The Rebellion

For the righteous pilots who always have their masks on as required, you can stop reading. We bow down to your professionalism and honor your self-discipline. For those of you smirking, let's talk.

Technology has improved immensely since this rule was put in place and airplanes are flying even higher. We know about the Payne Stewart accident and everything there is to know about hypoxia. I've been in an altitude chamber and listened to my normally non-humorous co-captain give the answer to 1+1 as "one thousand, one hundred onety-one" as he laughed his way through hypoxia. It is deadly, and we know it. But the steel horses we fly are now so self-aware and self-sufficient, they tell pilots when the cabin pressure is too high. They indicate trends, sound alarms, bells, warnings and automatic pax mask release. Automatic Emergency Descent Systems in some aircraft will automatically descend to MSA if pilots fail to respond to a cautionary alert. This system will even sidestep off-track to avoid traffic conflict.

For the explosive decompressions at FL510 (or even rapid, depending on the situation), we know we're pretty much doomed and the mask won't be much help as our internal pressure exceeds what is humanly possible to stay alive. The instant pain will be overwhelming, and hypoxia will be instant, even with a pressure demand mask. If we have an explosive decompression up there, something is seriously, structurally wrong and an O2 mask won't fix that. A gradual decompression is just as deadly (and more probable) because you don't sense it before hypoxia settles in…but the airplane will.

Pressurization incidents still happen all the time. Sometimes pilot-induced (forgot to turn on bleed air, system set to manual, etc.), but the reliability of modern business aircraft pressurization systems is extraordinary. But, like I said, incidents happen all the time so should we wear our masks like the rule states?

Here's the first dilemma; these masks were not meant to be worn all the time. They're designed for an emergency, which is temporary. The requirement to use these masks constantly during normal operations goes against how the system and aircraft were designed and how an emergency oxygen system was meant to be used.

The Reality

When pilots put on the mask, their environment changes. They are instantly trapped and confined, communication takes effort, and CRM is disconnected. It's hard to move, the pressure on your head and face is fatiguing, and consistently sucking on higher levels of oxygen is harmful, if not toxic.

We normally breathe air that is 21% oxygen at sea level. That ratio is the same at FL510, but because of the reduced pressure (molecules farther apart), we can't get that ratio into our lungs. But, that's outside; the cabin inside might be around 6,800 feet. I live at 8,500 feet in Colorado. Our bodies are getting what we need, so now we add on supplemental oxygen and start breathing it, for hours at a time…over a lifetime.

Toss in some germs next. When I was flying at the airlines (we have different rules which I won't get into, but same concept as Part 135), we would always check our oxygen masks before departure. We'd put them on, test the microphone ("Luke, I am your father…") and put them back. At night, we'd often take a "sip" from our masks as we started our descent which acted like a shot of caffeine. We all did…which meant we all were exposed to each other's germs too. We had the provided wipes, but breathing warm, moist air into these masks aren't going to get clean by a pilot doing a quick swipe. And, we use alcohol wipes, which probably isn't good to be mixed with O2 and degrades the materials of the mask.

For the employees of the FAA and NTSB reading this, they have already smacked their foreheads and have mumbled something about pilots always complaining. It's just an oxygen mask, just put it on! The point to all this is that the reality is: pilots don't put on the masks, but they also don't like breaking the rules. Pilots don't want to be deviants and those righteous pilots from the previous paragraph will look down at us.

There should be strict oxygen and cabin pressure rules, the same for all ops (Part 91, 135, 121 etc. should all be the same), but they should be based on equipment capabilities, cabin altitude and service ceilings - and more focused training (and practice) for using quick donning masks. Maybe simply adding a requirement to check cabin pressure after a frequency change or every 15 minutes above FL250 would suffice.

This is not pilots asking for any rules to be relaxed. It would be a genuine increase in safety to use the oxygen systems as they were meant to be used, to train on how they were meant to be used, and to train on the vigilance of monitoring the pressurization system. What the FAA has been asking of pilots all these years is to go against the manufacturer's intended use of an aircraft system. So, who is actually breaking the rules?

It's quite possible that this temporary amendment activation leads to a permanent rule change, but it's up to pilots to continue being diligent and respecting Murphy's Law.

Link to Federal Register

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