Definition
Wearable devices that deliver supplemental oxygen from an aircraft's oxygen system to the pilot or passengers, used to prevent hypoxia when flying at altitudes where the air contains insufficient oxygen for normal body function.
Plain English
Masks worn over the nose and mouth that feed extra oxygen to the wearer when the air at altitude is too thin to breathe properly.
Context Anchor
Seen in high-altitude operations, emergency equipment discussions, and flight training that covers lack of oxygen at altitude.
Why Pilots Care
Prevents hypoxia and loss of consciousness during flights above 10,000 feet or after sudden cabin depressurization.
Grounding Statement
If the airplane is high enough that normal breathing is not enough, an oxygen mask is the part you put on your face so oxygen can reach your lungs.
Intuition Check
Do not think of oxygen masks only as emergency passenger equipment. In aviation, oxygen masks may also be planned equipment used by pilots and crew during high-altitude flight.
Example Sentence 1
Above 12,500 feet for more than 30 minutes, the required flight crew must use oxygen masks to stay alert and safe.
Example Sentence 2
After the cabin pressure warning, the pilot immediately reached for the oxygen mask on the panel.