Learning how to Use and Clear an AGA mask
The Desired Learning Outcome (DLO) of clearing an AGA is as follows. Two years from at 0200 hrs, you are called to a submerged vehicle with two passengers. It is cold and rainy. The team is in rescue mode. You are the primary diver. The tender’s good calculations put you right on top of the vehicle. As you descend on it, the bottom of your AGA mask hits the top of the slightly opened driver’s door, and your AGA is pushed off your face and begins free flowing. No problem, you tip your chin to your chest and access your pony regulator mouthpiece. You calmly reach up for your AGA intermediate pressure hose, don the mask, clear it, and continue with the job. The tenders ask if you are okay either by line signal, or preferably by an electronic communication system, and after you respond that you are okay, calculate a new maximum dive time based on the air lost during the free flow.
The DLO is about surviving accidental mask dislodgement or full removal. Some teams may elect to abort a dive once an AGA has been fully removed, others will make it the diver’s/tender’s decision. In either case, divers need to demonstrate complete comfort, confidence, and competence in the skill of doffing, donning, and clearing their full face masks underwater before they are allowed to dive with them in open water. Without this ability, which needs to be reinforced routinely with frequent practice, divers may not have the confidence to remain calm should their mask have a problem. This lack of confidence could end in yet another needless fatality.
So the DLO is survival. The objective is “While underwater, remove the mask without it free flowing, switch to you pony mouthpiece, breathe comfortably 3-4 times, don the mask and comfortably clear the mask, and breathe from it comfortably 3-4 times.” This is first done while kneeling, while in an alligator position (prone), and then while slowly swimming.
Okay, let’s get started. Most divers start this in a pool. We often do this in shallow water in open water sites.
Step1: Practice donning and doffing the mask on land while wearing dive gloves with eyes closed. Every movement should be slow, gentle, and deliberate. If you allow divers to move quickly with their movements, then they are that much closer to stress should something go wrong. Slow makes actions smooth, effortless and calm.
Step 2: Don the mask and descend to shallow water. Breathe, move around, get used to how it feels when you are in different positions. Make sure to breathe with your mouth, NOT your nose. Nose breathing will increase the risk of aspiration should you need to switch to a pony. Make normal inhalations, slightly longer and gentler exhalations. Exhale the same amount of air as the inhalation, but do so in a longer time period. Have someone count your breaths. Aim for a 6-12 breaths per minute rate. If the rate is higher, then you need to work on slowing down the breathing. Concentrate on the exhalation. Relax. Decrease your CO2 level.
Step 3: Practice clearing your ears by pushing on the little tab on the oronasal plate. If you are using comms, that plate wont have the tab anymore so push in on the lower part and play with it to see what works best to get the nose piece under your nose. If the nose piece is at the highest setting and it still doesn’t occlude your nose, then cut a piece of neoprene and glue it on the top of the nose piece with Aquaseal. The thickness of the neoprene needed will depend on how far away the nose piece is from you nose. Try occluding your nose, putting your tongue on the roof of your mouth, and swallowing (without blowing). Then swim around some more and practice gently clearing your ears.
Step 4: kneel on the bottom with a partner. Doff your mask. If you have a positive pressure mask make sure to hold the lever to prevent the mask from freeflowing. Calmly switch to your pony, that is hopefully hung on a quick release neck strap. Keep the mouthpiece in the holder while using it, so that when you stop using it, it will still be there ready for the next time you needed it. After breathing 3-4 times comfortably on the pony mouthpiece, gently surface. Do this a few times. Do this while slowly swimming.
This step is very critical. It will train you to go to your pony air instead of bolting to the surface if the mask is every accidentally dislodged on a real dive.
Step 5: While kneeling remove the mask and switch to your pony. Breathe comfortably for 3- 4 breaths. Retrieve your mask, don it like you were taught (grab the bottom two neck straps, pull the spider over the back of your head, pull the necks straps down to your neck, spit out the pony regulator, then get your chin in the chin cup). This technique of mask donning not only prevents your hood from being pulled back and or your hood vents from being ripped out, but it also allows you to keep the pony in your mouth until the very last minute.
With the mask on your face use one hand to press the face plate hard against your face. Keep your head in a forward looking position so the water can drain out the bottom exhaust valve. Keep your eyes closed, and gently, briefly hit the regulator purge button to clear the mask. Later you will most likely be able to clear the mask by simply exhaling. Take a gently sip of air with the expectation that you may get some water with the air. Exhale and the mask should be clear. Now tighten the middle, then the bottom, then the top strap. Remember do not tighten the top strap more than two inches.
This is important. If you are not able to clear the mask before you need air, then tuck your chin, lift the mask away from your mouth and access your pony mouthpiece. Breathe on your pony until you are full comfortable again. Once you are ready, pull the mask back to your chin and try to clear it again. Do not stand up if you are having problems. Learn to trust your pony. You always have air a few inches from your mouth. If you allow yourself to surface instead of using the pony, then you are training yourself to bolt to the surface if something goes wrong. Go the pony (said with a Yoda voice). Go to the pony, and you will survive. The surface may look tempting like the Dark side was tempting enough to seduce a Jedi. But as a public safety diver you can resist it, just goooo to the pony mouthpiece.
Step 6: The finale. Descend, remove the mask, access your pony mouthpiece, breathe a few times comfortably, retrieve the mask, don the mask, clear the mask with confidence and smoothness. Then do this while swimming slowly with eyes closed. Have a partner guide where you swim. Voila.
Then, perform this skill after fin kicking while holding a wall or another partner to make yourself out-of-breath to simulate more realistic stress conditions. Once you are a pro, play with this skill in different body positions, supine, prone, upside down, etc.
Remember to practice these skills regularly.
John Hott from OTS adds these tips:
“Only one thing I might suggest. When you push on the drain (purge) button, you are actually closing the exhaust side of the reg. The sealing disc is pressed against the leading edge of the diaphram, thus closing the exhaust. Although the water seems to go somewhere, mostly out of the skirt. You’ll find that it’s helpful to pull the chin out a bit and then purge. After donning and clearing the mask, close your eyes and take a sharp inhale, this to help clear the inhalation vents under each eye of any remaining water, otherwise, there’s an annoying spray and gurgle with every breath. It may need to be repeated a couple of times to clear the water out of the channels.”