BUT, here is the question -- SHOULD all buddy pairs be able to do this? That is, should all buddy pairs be able to reliably and comfortably share air and swim together in a horizontal manner?
In so far as 'skillset' - yes, it should be achievable. The actual skill to 'perform a safe ascent whilst sharing air' should be repeatable whilst diving horizontally (rather than ascending vertically) in the water.
However, having capability to perform an activity is not, in itself, a credible reason to perform that activity.
An additional question, SHOULD all buddy pairs practice air sharing on some sort of a regular basis? And if so, in what ways should the practice be done?
I believe that all core skills should be practiced frequently. A skill is only as good as the last time it was practiced correctly.
As with an emergency drill, the issue of 'ingrained reaction' is critical. The skill is designed to permit divers to ascend safely to the surface, when OOA/LOA, with the support of their buddy. In that respect, if forms a prime foundation that underpins the whole notion of 'recreational' dive training.
To properly ingrain air-sharing as an emergency ascent protocol, I believe the following critical skills and mindset are necessary
in practice:
1. Immediate recognition and acceptance of OOA/LOA as an
emergency circumstance
2. Recognition of buddy as a source of air and safe ascent - a preferable resolution to the emergency circumstance.
3. Swift location and acquisition of the buddy's emergency air source.
4. Maintenance of firm mutual, physical contact between the buddy and receiver (
unless specific long-hose capacity is trained for - even then, mutual physical support can be a critical factor, especially when reaching the surface)
5. Safe ascent procedures, displaying pro-active planning (
actions on surfacing - acquisition of positive buoyancy etc), buoyancy control (
oral, if OOA) and ascent speed.
6. Stress management and emotional control techniques.
If the practice does not enable those critical attributes, or worse... actively degrades them, then it can be counter-productive. That is one reason why I view casual use of air-sharing, as a non-emergency procedure, to be potentially damaging to emergency response reactions. Whilst comfort in the act of air-sharing is valuable, it should not be at the expense of developing complacency or hesitation in a LOA/OOA situation.
I say this because I have, on occasion, found myself in low-on-air or out-of-air situations underwater.... sometimes knowingly and, otherwise, avoidably. My only explanation for that is complacency. I have a high tolerance for stress and a high degree of comfort in air deprivation scenarios. I won't bat an eyelid if I find myself sucking fumes from my tank at depth - and that does truly scare me. I have to rationalize the danger I am in, because my comfort level dictates that any sense of urgency or distress will be missing. Of course, it's very beneficial that panic isn't an immediate likelihood, but having an ingrained psychological and physical response to OOA/LOA as an emergency situation is also critical. Too much comfort
can be a bad thing.... and it's often the cause of avoidable incidents amongst the experienced diver demographic. The solution, in my opinion, is the clear designation of emergency procedures as automated responses to emergency scenarios.... no ambiguity.