This course provides training and experience required to competently utilize air for dives up to 55 msw / 180 fsw that requires stated decompression, utilizing nitrox mixtures or oxygen during decompression. The objective of this course is to train divers in the proper techniques, equipment requirements, and hazards of deep air diving to a maximum of 55 msw / 180 fsw utilizing nitrox mixtures or oxygen for staged decompression.

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

Upon successful completion of the course, graduates may enroll in the TDI Advanced Wreck Course, TDI Entry Level Trimix Course, and TDI Advanced Trimix Course.

A student must:

• Be a minimum age of eighteen (18)
• Have a minimum certification of TDI Advanced Nitrox Diver & TDI Decompression Procedures Diver or equivalents
• Show proof of a minimum of 100 logged dives, of which 25 must be deeper than 30 msw / 100 fsw.

Training Material & Equipment Required:

• TDI Extended Range Entry Level Trimix Diver manual
• Deep Diving: An Advanced Guide to Physiology, Procedures and Systems, by Bret Gilliam
• Bottom mix cylinder
  • Cylinder volume appropriate for the planned dive & student gas consumption
  • Dual outlet valve, double manifold or independent doubles
  • Labeled in accordance with TDI standards
• Travel mix cylinder(s) if used
  • Cylinder volume appropriate for the planned dive & student gas consumption
  • Labeled in accordance with TDI standards
• Decompression mix cylinder(s)
  • Cylinder volume appropriate for the planned dive & student gas consumption with submersible pressure gauge
  • Labeled in accordance with TDI standards
• 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
• 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 planned depth
  • Lift bag with at least 25 lbs of lift
• Exposure protection appropriate for local diving condition
• Slates/wetnotes
• Jon-line and other rigging lines as dictated by site conditions
• Access to an oxygen analyzer
• Two line-cutting devices
• Other equipment requirements may apply, check with instructor