Provides training required to competently and safely utilize breathing gases containing helium for dives that require staged decompression, utilizing nitrox and/or oxygen mixtures during decompression to a maximum depth of 100 msw / 330 fsw. The objective of this course is to train divers in the benefits, hazards and proper procedures of utilizing custom oxygen / helium / nitrogen mixtures as breathing gases.

Upon successful completion of the course, graduates may engage in technical diving activities utilizing custom trimix mixtures without direct supervision as long as the diving activities, areas of activities, and environmental conditions approximate those of training. 

A student must:

• Be a minimum age of eighteen (18)
• Have a minimum certification of TDI Extended Range Diver or Entry Level Trimix Diver or equivalent
• Show proof of a minimum of 100 logged dives with 25 deeper than 100 fsw / 30 msw
• Prior logged experience with double cylinders and any other unfamiliar equipment

Training Material & Equipment Required:

• TDI Trimix diver manual
• Bottom mix cylinder
  • Cylinder volume appropriate for the planned dive and student gas consumption
  • Dual outlet valve, double manifold or independent doubles
  • Labeled in accordance with TDI standards
• Travel mix cylinder
  • Cylinder volume appropriate for the planned dive and student gas consumption
  • Labeled in accordance with TDI standards
• Decompression mix cylinder
  • Cylinder volume appropriate for the planned dive and student gas consumption
  • Labeled in accordance with TDI standards
• Suit inflation cylinder (required for drysuit divers only)
• Regulators
  • Primary & primary redundant regulators required on all bottom mix cylinders
  • Submersible pressure gauge required on all primary & bottom mix cylinders
  • A contingency use long hose second stage should be designated and appropriately rigged to facilitate air sharing at depth if necessary
  • It is strongly recommended that 4 required regulators be all DIN or all yoke
• Redundant depth & timing devices
• Air decompression computers allowed for use as depth & timing devices
• Buoyancy compensator appropriate for equipment configuration
• Redundant light system if needed for site conditions
• Ascent reel with lift bag/surface marker buoy
  • Appropriate for maximum planed depth
  • Lift bag with at least 50 lbs of lift
• Exposure protection appropriate for local diving condition
• Slates/wetnotes
• Helium analyzer
• Two line-cutting devices
• Other equipment requirements may apply, check with instructor
• TDI Advanced Trimix Diver manual