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There are two main types of supplemental oxygen devices in light aircraft:

  • Cannula:

    Precise Flight standard cannula

  • Oxygen mask:

    Precise Flight microphone mask

What are the major differences between these two devices? Is one more suitable for specific siutations than another, or is it just a matter of personal preference?

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up vote 8 down vote accepted

Cannulas are not effective above medium altitudes, and the FAA prohibits their use above 18,000 feet (FAA brochure on Oxygen Equipment, PDF). Because they only place oxygen at your nose, you don't receive oxygen when talking or breathing through your mouth, while a mask covers both nose & mouth. This is, obviously, not great.

Cannulas are also less comfortable than a nice-quality mic/mask, but that's my personal opinion. A lot of pilots do prefer cannulas for comfort at lower altitudes, as they're easier to don and allow you to continue using your normal headset mic boom. For most pilots, especially those flying normally aspirated aircraft types, it's a matter of preference.

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Cannulas also cannot deliver as high a quantity of oxygen as masks – SSumner Apr 14 '14 at 10:19
@SSumner yeah, that's why they're less effective at higher altitudes. The bigger problem, though, is that if you talk a lot, you're breathing through your mouth and not your nose, which means you're gonna get less oxygen overall. – egid Apr 14 '14 at 17:34
One other big disadvantage of cannulas is that they dry out your nose. – rbp Mar 22 '15 at 15:00

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