TDI Mixed Gas CCR Diver
Expand your CCR capability with helium, reduce narcosis, and execute deep technical dives with precision and control
Duration
5 days, 6 dives
Max Depth
60m / 200ft
Level
Technical (CCR Advanced – Mixed Gas)
Next Step
TDI Advanced Mixed Gas CCR
Overview
The TDI Mixed Gas CCR Diver course is the advanced-level CCR certification, enabling divers to use helium-based diluent gases for deeper technical diving.
By integrating helium into the breathing mix, divers reduce narcosis and improve clarity at depth, allowing safe and controlled exploration beyond air diluent limits.
Training focuses on advanced gas planning, decompression strategy, PO₂ management, and failure response, where precision and discipline are critical.
Divers operate a unit-specific life-support system under increased depth, decompression, and task loading, requiring full control of bailout strategy, gas selection, and system management.
At N9BO℠, this course is delivered as high-discipline technical training, developing advanced operational capability and decision-making.
Course Facts
- Course name: TDI Mixed Gas Closed Circuit Rebreather Diver (Unit Specific)
- Level: Technical CCR (mixed gas / advanced level)
- Minimum prerequisites: Minimum age 18, Minimum 50 CCR dives / 50 hours on unit, TDI Air Diluent CCR Diver (or equivalent)
- Ratio: Maximum of 2 students per instructor (small groups recommended for quality training)
- Configuration: Unit-specific CCR with mixed gas diluent (≥16% O₂), multiple bailout systems
- Depth / environment: Maximum depth 60m / 200ft, Mixed gas dives beyond 40m required, Decompression diving mandatory
- Format: Academic development + unit workshop + confined water + open water dives
- Duration: Typically completed in 5 days (Minimum 6 open water dives with at least 360 minutes accumulated bottom time)
What You’ll Learn
- Plan and execute mixed gas CCR dives using helium diluent.
- Calculate and manage Equivalent Narcosis Depth (END).
- Control PO₂ setpoints throughout deep and decompression phases.
- Manage multiple bailout cylinders and contingency planning.
- Monitor CNS exposure and oxygen toxicity limits.
Prerequisites
- Be at least 18 years old.
- Have a minimum of 50 logged dives / 50 hours on the unit.
- Hold TDI Air Diluent CCR Diver (or equivalent).
- Be medically fit for diving.
FAQ
Mixed gas CCR diving uses helium-based diluent gases (trimix) to reduce nitrogen narcosis and enable deeper dives with better clarity and control.
You are certified to a maximum of 60 metres / 200 feet, using mixed gas diluent and planned decompression.
You must complete a minimum of:
- 6 open water dives
- 360 minutes total bottom time
- Oxygen toxicity at depth
- Hypoxia due to system failure
- CO₂ buildup
- Gas management failure during decompression
You are qualified to conduct unit-specific CCR dives using mixed gas diluent (trimix), managing deep decompression profiles, helium-based gas planning, and advanced bailout procedures within your training limits.
Ready to Go Deeper on CCR?
Send us your CCR experience and certifications. We’ll train you to execute deep mixed gas dives with precision, discipline, and full system control.
Go Pro with Mixed Gas CCR Instructor
Advance into elite-level instruction and train divers in deep CCR mixed gas operations, decompression strategy, and life-support system mastery.
