Limitations of TDI helitrox?

[dylanfromwinnipeg]

this is mostly an academic question as I have no intentions of pushing limits here. But I got into a debate with my (new) instructor today about what I am and am not allowed to do under my TDI helitrox cert.

Is there any limit to how many tanks or different gas mixes I can use on a dive (assuming I stick to < 45m and < 35% He)?

I was under the belief that there is no tank limitation, but possibly a number of deco gas limitation (although looking at the c-card it doesn’t mention either as a limit).

If I did a 4 tank dive, 2x SM EAN32, 1x stage EAN32, + 1x deco bottle 100% O2. Is that allowed with a helitrox cert?

 

[Whitrzac]

There is no limit.
It would be the no different than running some lp149s overfilled

 

[tursiops]

Attached are the Standards for the Helitrox course.
You are trained on back gas and one deco gas. Not stages!
Use of more than one deco gas, and/or stages, is in the next class...either Extended Range or Trimix.
The issue is managing multiple regulators and tanks without getting confused.
Mind you, the cert only says what your training is; it doesn't say what you can't do.

 

[Wibble]

Remembering back to my ANDP+Helitrox, it was one deco bottle and limited to less than 35% helium.

No mention of other gases, but the spirit of the rules were you weren't to push it; just a twinset and a single deco gas.

But the letter of the rules... Fill yer boots!

The Normoxic/Extended Range introduces two deco tanks and takes you through the changeover drills from one deco gas to another, plus the planning for failures of one gas.


Edit...

Just looked at my Helitrox card from 2016:

 

[justinthedeeps]

If I did a 4 tank dive, 2x SM EAN32, 1x stage EAN32, + 1x deco bottle 100% O2

What's the dive plan / rationale for these choices? I don't get it
Did you use 100% on your helitrox course?

 

[dylanfromwinnipeg]

Did you use 100% on your helitrox course?

I did adv nitrox together with helitrox, and we def used 100% O2 on the course.

 

[justinthedeeps]

What kind of dive profile(s) were on the course, and/or planned now?
Do you really need a third cylinder of EAN32?
How are you getting a dive where three cylinders of EAN32 + a 100% is optimal?
Is there not a solution that involves the two SM cyls bottom gas, and a single deco stage (mix TBD, possibly not 100%)?

 

[dylanfromwinnipeg]

like I said my question is more academic than practical (I’m also stage cave certified which I think makes some of these conversations moot). With just TDI helitrox does that allow you to dive X tanks? Or X diff deco gases?

 

[justinthedeeps]

So the question is just whether it covers or qualifies for using more than one stage or deco cylinder?
Did you cover multiple deco stages and 'bottle rotations' in the helitrox course?

If I remember correctly the PADI 40 and 45 metre levels with just a single stage (usually 50%), with the 45m one being helitrox optional; oxygen gets introduced as a second stage at the 50 metre level (the third minicourse ) That was years ago, but I'm pretty sure they were approximately copying what other agencies do.

 

[justinthedeeps]

I think I heard some instructor drowned from ox-tox while sidemount diving because of multiple stages confusion recently