Time of useful consciousness (TUC)

The comfort of a pressurised cabin includes on the other side also a danger: what if the pressure decreases? Slow decompression, for example as the result of a leak in the cabin, brings on the symptoms of hypoxia slowly and maybe unnoticed.

Rapid decompression, for example as result of technical failure of the cabin, brings up oxygen starvation very quickly.

The remaining Effective Performance Time shortens the higher the altitude at which the decompression happens. This fact can be expressed in other words by the  Time of Useful Consciousness - TUC. This CBT illustrates the correlation of altitude and useful oxygen and how fast you would have to react when pressure is lost at higher altitudes.

The two columns show the pressure decrease when you move the aircraft. The left column indicates the outside air pressure and its oxygen percentage (21%) - and the right column indicates the oxygen partial pressure outside our body compared to the oxygen partial pressure inside our body, including possible oxygen saturation of the blood.

Note: Sufficient oxygen saturation of the blood ends at 88 % !

If you let go the mouse button which moved the aircraft, the remaining time of useful consciousness appears as "time remaining" to react. The oxygen symbol right of the time indication appears when you need additional oxygen.

• Now its your turn to act quickly !
  
  • Click on oxygen below your seat. You find the oxygen mask and the oxygen bottle. Drag the mask to your face (be precise to avoid a leaky mask).
  • Now you have to open the  oxygen flow. Click on the oxygen bottle and you find the wheel to release the oxygen (turn towards the "correct" direction).

Did you get additional oxygen before the time elapsed?