Total Coverage: The FAA Oxygen Mask Study

By Scott Spangler on January 14th, 2019

Total Coverage: The FAA Oxygen Mask Study

o2The FAA Reauthorization Act of 2018 sometimes asks more questions than it answers. For example, what was behind Section 536. Oxygen Mask Design Study?

It requires the FAA to review and evaluate the design and effectiveness of commercial oxygen masks. “In conducting the study, the Administrator shall determine whether the current design of oxygen masks is adequate, and whether changes to the design could increase correct passenger usage of the masks.’

Diving into the Internet, this week’s research suggests that Section 536 was inspired by Southwest Flight 1380, where an uncontained engine failure led to the decompression of the 737’s primary people tube. Given the section’s focus on “correct passenger usage,” it seems safe to assume that this photo was an inspiration.

dixie cupGiven the Dixie-cup design of the ubiquitous commercial airline oxygen mask, which most of us have only seen in the hands of a flight attendant during the takeoff safety briefing that we’ve heard so often that we no longer pay attention to, it is easy to imagine how a real emergency could lead us to make it up in a panic. Sure, there’s a how-to pictograph on the rebreather bag, but who remembers that when panic is front of mind?

Here’s my question: what took so long? Too few actual decompression incidents, not enough Twitter photos during these events, or both?

I’m no human factors expert, but it seems logical to me that if you present a passenger, panicked or not, with a more anatomically shaped mask that makes clear where your nose and chin go, people would have at least a 50-percent chance of getting it right. And if they didn’t, feeling the breeze on their necks might give them a clue.

The FAA offers some interesting insight in Oxygen Equipment: Use in General Aviation Operations.

ga maskThe general aviation oral-nasal (mouth and nose) rebreather is a simple, inexpensive mask with an external plastic bag that inflates on exhalation. The bag mixes your exhaled air with the incoming 100-percent oxygen. According to the brochure, such masks will “supply adequate oxygen to keep the user physiologically safe up to 25,000 feet.”

The GA mask looks like the airlines’ drop-down Dixie cup, but it works differently. The Dixie cup “uses a series of one-way ports that allow a mixture of 100 percent oxygen and cabin air into the mask,” the FAA booklet says. “Exhalation is vented to the atmosphere; as a result, the bag does not inflate,“ (and I couldn’t find a reason why it’s there, either).

Finally, “this mask can be safely used at emergency altitudes up to 40,000 feet.” It didn’t say anything about keeping passengers “physiologically safe” at that altitude. But when still breathing is what really matters…

Still, the question remains, one-way valves aside, if the GA mask and Dixie cup are essentially the same, why not used the anatomically suggesting GA mask on airliners? It will be interesting to see what the FAA study has to say. Stay tuned. – Scott Spangler, Editor

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One Response to “Total Coverage: The FAA Oxygen Mask Study”

  1. Chris Fera Says:

    Airliners typically use oxygen generators that work by chemical reaction (essentially a combination of chemicals that heats and produces oxygen). The bags attached to those masks are theoretically used to store excess oxygen that is produced by the reaction because there is no way to slow down the production of the gas. That said, not sure how effective they are at that in real life as I’ve never seen one in action.. knock on wood.

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