Assertion: supplemental oxygen | /r/HasProperty | needed
Facets:
value: for flying more than 30 minutes
type: TEMPORAL
Source sentences:
text: Supplemental oxygen is needed for flying more than 30 minutes at cabin pressure altitudes of 12,500 feet or higher, pilots must use oxygen at all times above 14,000 feet and each occupant must be provided supplemental oxygen above 15,000 ft.