__A search for the word hypoxia in NTSB accident reports for the past decade turns up just 15 occurrences. Of these, five do not involve our usual understanding of hypoxia as incapacitation due to protracted exposure to high altitude without supplemental oxygen; the references are, instead, to carbon monoxide poisoning from a leaky muffler, elderly or ill pilots who were chronically hypoxic even on the ground, and one case of GLOC or G-induced loss of consciousness in a pilot practicing aerobatics. A sixth case involved loss of control in a Learjet 24D in which no clear cause could be determined; pressurization failure was mentioned as a possibility, but only hypothetically.
During that 10-year period, then, there was on average fewer than one fatal accident per year in the United States in which hypoxia could plausibly have played a role. This is remarkable, first, because dire warnings about the dangers of hypoxia abound, and second, because it is practically certain that a great many pilots fly while technically hypoxic.
