Originally Posted by Above The Clouds
As for your statement regarding hypoxia, read about the subject first it might give you an understanding why they couldn't turn on a phone let alone use it
Couldn't agree more.
Hypoxia as a possible cause has been bandied about often enough and deserves some light being thrown on it.
It’s basically an incomplete interruption of O2 to the brain which uses 20% of body O2 intake. Consciousness is usually lost in about 15 seconds and irreversible brain damage starts after 4 minutes or so.
(Anoxia is complete interruption of brain supply of O2 eg hanging/strangulation)
The possible causes of hypoxia in an a/c in flight could possibly be high altitudes (unpressurised), smoke inhalation and CO inhalation.
The response of the body to hypoxia is to speed up the blood flow to the brain (max of 2x normal).
If this compensation is insufficient, symptoms start to appear - problems with concentration, attention, co-ordination and short-term memory, which may be relatively subtle to begin with. There may be headache, light-headedness, dizziness, an increase in breathing rate and sweating. There can be a restriction in the field of vision, a sensation of numbness or tingling and feelings of euphoria.
As the degree of anoxia becomes more pronounced, confusion, agitation or drowsiness appear, along with cyanosis. There may be brief jerks of the limbs (myoclonus) and seizures, both resulting from the damaging effects of lack of oxygen on the brain. If the anoxia is severe, it will result in loss of consciousness and coma.
In a rapidly developing situation (from fire for example), the window of about 15 seconds leaves very little time for pilots to take proper action. O2 masks would require presence of mind and only if something else has not arrested the pilot’s attention or even prevented that action.
Rapid fire progression in the cockpit with a locked doors and fire-knocked out or pilot-actioned comms, leaves the cabin pax and crew isolated, wondering and not taking action until they too late as they become incapacitated.
Hope this sheds some light. However this scenario is only possibly true IF fire is the cause. And one would expect the a/c to crash and be found not too far away. Tanks loaded with fuel on the first leg of the flight would also not help the a/c get too far.