Fine tuning

So imagine you jumped with the Tritium altimeter on a great FS skydive. You use the colours to track, wave off, then pull. Then something goes wrong.

You have a malfunction. You’re jumping a highly loaded main and it opens with twists, and quickly throws you into a spin. How can Tritium help you keep altitude awareness?

Ideally, you pulled at the first red indication (4000 feet) so you have some altitude to try to fix the malfunction. However, every skydiver should have a ‘decision altitude’ and a ‘do not cut away’ altitude. There are no strict recommendations as this will depend on the type of canopy you are jumping and your personal preference.

However, AADs are designed to fire at terminal velocity at around 750 – 900 feet, and a sub-terminal cutaway below 1000 feet will likely result in serious injuries unless using a Skyhook or MARDS reserve.

Upper: canopy mode, 1300 feet. Lower: canopy mode, 900 feet

Therefore, we have changed the AMBER indication for the canopy mode to 1000 feet (instead of 800). This colour could then serve another purpose: serve as an indication, during a malfunction, to NOT cut away and instead just deploy the reserve (2 out) to try to mitigate risk as much as possible. Of course, malfunctions below this altitude are extremely undesirable and we recommend that you decide on a hard deck altitude and be under a stable and controllable canopy BEFORE the amber light comes on.

So, if Tritium is AMBER in canopy mode, you have crossed 1000 feet. This may even serve a third purpose: aircraft landing patterns are usually performed at a circuit altitude of 1000 feet AGL (recommended in FAA AC90-66A Para. 8c), and most drop zones specify that you do not cross the runway below 1000 feet. Therefore it is recommended that you should cross any runways on your landing pattern before the AMBER indication comes on.

So it is important to remember:

  • set a hard deck altitude, and be under a stable canopy BEFORE amber light goes on;
  • cross any runways BEFORE amber light goes on;

This should not affect your decision altitude or hard deck, which you should choose for yourself – personally, my decision altitude is 2000 feet. However, Tritium should hopefully increase your awareness by indicating when it has crossed 1000 feet.

We highly recommend reading these articles on Skydive Mag to help you keep informed about these important issues:

Stay safe jumping!

Blue skies!