Aqualung Legend LX First Stage Failure at depth

[reefrat]

Let’s see, so far:
A conical filter installed upside down and modifications to a perfectly good case design, not to improve performance but to avoid patent issues.
Specialized tools and knowledge/ non-intuitive techniques required to assemble and torque correctly.
A design requiring close tolerances and intolerant of incorrect assembly and torque settings.
Mysterious failures causing cessation of gas flow with multiple possible causative factors.

Sounds like a lot of potential issues and failure points created to avoid one issue resultant from poor diver training and practices. I doubt any real engineering hazard ID and hazop studies were done on this change before it was put into production.
I have one of these first stages in Din and when the yoke adapter is screwed on you can clearly see the ACD open before installing on the tank valve, I would not own one with a yoke!

 

[JackD342]

My Legend and my rental ACDs have been trouble free.
ACD is just a “nice to have” on my own gear, but really appreciate it on rental used by divers unlikely to report back if they flood it - why would they care?

Just sayin’ ...

 

[Diving Dubai]

I do have one THEORY of how one might loosen a properly torqued unit.

Would also the "practice" by some of twisting teh 1st stage to assist in releasing an "over tighten" yoke screw accomplish the same thing?

It's been and interesting thread, thatks to @JackD342 & @rsingler for their investigative work on the yoke variant.

I learnt something other than the obvious that yoke always will be an inferior design which is a given

 

[JackD342]

Would also the "practice" by some of twisting teh 1st stage to assist in releasing an "over tighten" yoke screw accomplish the same thing

I don’t think so. Can’t see where any counterforce would act on the valve.

 

[Fyffer]

Glade u are ok. So both your rega would not work because of the 1 st stage. I’m very new just asking.

 

[Couv]

Sounds like a lot of potential issues and failure points created to avoid one issue

My friend, you forgot one thing in your (almost) comprehensive post. This device is mostly a sales gimmick. It matters not if the target market is a dive shop or the unfortunate souls who had to pay the extra cost associated with the engineering, manufacturing, and marketing of an unneeded complication substituted in place of a proven design.

 

[Diving Dubai]

I don’t think so. Can’t see where any counterforce would act on the valve.

My derp

I was thinking about the shutter crown like the DIN but of course that can’t happen on the yoke

 

[JackD342]

My derp

I was thinking about the shutter crown like the DIN but of course that can’t happen on the yoke

yeah, I have done that on a DIN with yoke adapter in the past.

 

[JackD342]

My friend, you forgot one thing in your (almost) comprehensive post. This device is mostly a sales gimmick. It matters not if the target market is a dive shop or the unfortunate souls who had to pay the extra cost associated with the engineering, manufacturing, and marketing of an unneeded complication substituted in place of a proven design.

One man's "feature" is another man's "fluff," and yet another man's "competitive advantage." Ultimately, the market decides. A few years ago Aqualung thought a Quick Connect on the Titan/Calypso would be a great idea. The market spoke, and that was gone pretty quickly. And whatever happened to those folding fins with the locking hinge?

On the flip side, I bet the first time someone started adding an alternate airsource to a setup they were told it was an unnecessary and frivolous expense.

 

[reefrat]

One man's "feature" is another man's "fluff," and yet another man's "competitive advantage. Ultimately, the market decides. A few years ago Aqualung thought a Quick Connect on the Titan/Calypso would be a great idea. The market spoke, and that was gone pretty quickly. And whatever happened to those folding fins with the locking hinge?

On the flip side, I bet the first time someone started adding an alternate airsource to a setup they were told it was an unnecessary and frivolous expense.

The market will decide pretty quickly if there are more incidents and a recall!
If they can get it to work with the same degree of reliability that the rest of the first stage is known for then I can see some potential applications for this device- rental Regs might be one for sure. But they should go back to the situation where it was offered but not mandatory so that the rest of us that don’t need diapers or training wheels have a choice.