CASA media release - Thursday, 18 August 2005
New warning about hypoxia
Australian pilots are being given a timely reminder about the dangers of hypoxia.
People on board an aircraft which suffers a loss of pressure when flying above 10,000ft will suffer hypoxia.
This is a condition where the body is starved of enough oxygen to function normally and will lead to death.
At a typical cruising altitude for a large passenger aircraft of 30,000ft, a loss of cabin pressure leaves pilots, cabin crew and passengers with only 1 to 3 minutes of useful consciousness.
During this time reasoning and judgement is impaired, speaking becomes difficult, coordination is lost and visual information is not processed normally.
The Civil Aviation Safety Authority’s flagship safety publication, Flight Safety Australia magazine, features a story on hypoxia in the latest edition.
Aviation medical consultant Dr David Newman says pilots must be alert to the risk of hypoxia at all times.
“When in doubt, suspect hypoxia,” Dr Newman writes.
“Any symptoms at altitude should have you thinking of hypoxia, and dealing with that issue quickly, since it’s the most dangerous time-limited problem.
“Even if you think there is another cause of your symptoms, such as hyperventilation, you should still apply oxygen straight away. This is the fail-safe course of action.”
The symptoms of hypoxia include loss of short term memory, an increase in reaction time, mental ‘tunnel vision’, loss of muscle coordination, deterioration of hearing and impairment of vision.
Hypoxia will occur quickly when there is a rapid loss of cabin pressure, while time of useful consciousness drops rapidly the higher the altitude of the aircraft.
If passengers are instructed to put on their oxygen masks at any time, it is essential this is done as quickly as possible to avoid the start of hypoxia. Parents must fit their mask first, as any delay can impair their ability to help their children with masks.
CASA has a produced an educational video for pilots called ‘Oxygen first’ which explains the symptoms of hypoxia and how to take the appropriate action. As the title suggests, the first action for a pilot must be putting on their oxygen mask.
Media contact:
Peter Gibson
mobile 0419 296 446
Ref: MR0525