deep air diving skill practice
TDI Entry Level Trimix Course


This TDI HELITROX course is available in Phuket Thailand. This is the next course up after the TDI Advanced Nitrox Course or can be taken if you are an adventure/advanced open water diver with a deep specialty or intro to tec certified. This Course examines the theory, methods and procedures of planned stage decompression diving using helium in your breathing gas.

The TDI Helitrox Diver Course trains divers how to plan and conduct staged decompression dives to a maximum depth of 45 metres/150 feet. The most common equipment requirements, gear set-up, and decompression techniques are also presented during this course. Students are permitted to utilize enriched air nitrox and helium mixes with no greater than 35% helium content, and up to 100% oxygen for decompression diving.

This program is designed as a stand-alone course, or it may be taught in conjunction with TDI Advanced Nitrox and decompression procedures at the discretion of the instructor.

For this course you will need 2 manuals. This is one of the reasons why the course is more expensive than the Deco Procedures for example.

    1. TDI Decompression Procedures Student Manual or eLearning
    2. TDI Extended Range/Trimix Student Manual or eLearning

Your TDI Instructor will give you valuable information and skills, among the topics covered are:

    • Helium as a breathing gasEffects on narcosis
    • Effects on respiration
    • Effects as an insulator
    • Counter diffusion
    • HPNS

The TDI Helitrox course combined with the TDI Advanced Nitrox course form the foundation of all other technical courses.  After these two courses and some extra experience, the stage has been set for you to move on to other technical levels.

Some of the materials you will be using include the TDI Divers Guide to Decompression Procedures, US Navy or Buhlmann Air Decompression Tables (made of vinyl for easy in-water use and storage) The aim of this course is to train divers how to plan and conduct a standard staged decompression dive.   The most common equipment requirements, gear set-ups, decompression techniques and decompression mixtures (including Oxygen and Nitrox) are presented.


Student Prerequisites TDI Helitrox Course:

Minimum age:18 years
Min certification/diver level:Minimum certification of SDI Advanced Diver (with Deep specialty) or TDI Intro to Tech Diver, or equivalent + Advanced Nitrox Diver or taught at the same time
Min amount of dives:50 logged open water dives
Course Duration:3 days including 4 dives to maximum depth of 45msw
System:Open Circuit twin set, Sidemount
Prerogatives:After completing the Helitrox course, the successful candidate can engage in decompression diving to a maximum depth of 45msw with the use of Helium mixes with no greater than 35% helium content, and up to 100% oxygen for decompression diving.
Certification available through:TDI

Primary and secondary regulators (for back gas or Sidemount set-up)Two stage/decompression regulators
Mask + Back-up maskBCD (wing) and harness or Sidemount Wing (with a min lift of 40 pounds)
Depth gauge/computer Timing device and backup timing device
Appropriate exposure suit 3mm or 5mm Knife/cutting device and backup
Two inflatable signal tubesReel and spool
Slate and backup slateCompass
Torch and Back-up torches (Trimix Diving, Wreck diving and cave diving courses)Hood - for Cave, Deep and Wreck Diving
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We have added some important downloads for you. After you have transferred a deposit to secure the course and dates, please sign them and send them back to us via e-mail.