Combat Dive Closed Circuit Diving Fundamentals Practice Exam

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• Is it appropriate to forcefully blow out of the mouthpiece?
• Which action is included in the non-convulsive O2 toxicity management plan?
• How do depth and exertion affect scrubber performance?
• What is the primary method to prevent CNS oxygen toxicity during a dive?
• True or false: Oxygen toxicity can accompany confusion.
• What is the ideal working depth for combat dives?
• What are the two factors in the operational duration of the MK 25 UBA?
• Which depth corresponds to a single depth limit of 80 minutes?
• What is scrubber life and why does it matter on CCR dives?
• What is the output pressure range of the oxygen reducer?
• What is the role of the diluent gas in a CCR system?
• How many liters does the breathing bag hold during normal operation?
• Which of the following conditions is NOT a sign of confusion?
• An improper purge will always result in which dive injury?
• What is the primary function of the closed-circuit rebreather loop in combat diving?
• In which emergency procedure do you turn off the oxygen cylinder?
• How does an emergency oxygen supply function on some CCRs?
• What is typically included when inspecting gas charges and indicators in a CCR field maintenance checklist?
• Which statement best describes time-in-loop as it relates to scrubber performance?
• What is the purpose of a quick-reference card or SOP for CCR operations in the field?
• What is the primary function of a counterlung in a CCR system?
• What is one feature unique to the exhalation hose?
• Which factor is explicitly considered when calculating mission-specific gas setpoints for combat CCR dives?
• Which statement correctly describes how temperature affects the CO2 absorbent?
• Which depth has a single depth limit of 15 minutes?
• Which of the following is NOT a factor in the MK 25 UBA's operational duration?
• Which depth has the longest single depth limit of 240 minutes?
• What is the single depth limit for 50 fsw?
• What is the purpose of a bailout gas on a CCR dive?
• If an oxygen sensor fails underwater, which remedy is appropriate?
• Which items are typically included in a CCR field maintenance checklist?
• Which material is a modern CO2 absorbent used in CCR scrubbers?
• What PPO2 setpoint range is commonly targeted on CCRs for combat dives?
• Which item is NOT typically part of essential pre-dive checks for a CCR system?
• How should you store and maintain CCR gear after a dive to ensure reliability next time?
• What is setpoint drift and how should it be managed during a dive?
• What is manual oxygen addition in a CCR and when would you use it?
• Regarding convulsive events in divers, which is correct?
• During hypoxia treatment, what must be done when the diver is brought to the surface?
• What can confusion be a sign of in diving injuries?
• What is the role of bailout gas in CCR operations?
• How should buoyancy be managed when using a CCR in combat diving?
• What is the risk of using too small a bailout gas cylinder for a CCR dive?
• How can a diver detect a gas leak in the loop while underwater?
• What is a primary safety concern when a counterlung collapses or crushes during a dive?
• What is the minimum pressure required in the SECUMAR bottles?
• How can a diver verify that bailout gas is ready and within safe parameters before a dive?
• What are the three major components of the MK 25 Mod 2?
• What is the single depth limit for 40 fsw?
• Immediately after O2 enters the breathing bag, where does it go next?
• What part of the MK 25 allows O2 to be added manually to the breathing bag?
• Which statement about loop gas is correct?
• What is the recommended practice when you encounter unfamiliar CCR controls?
• Which option correctly lists the MK 25 UBA's two consumption rates in liters per minute?
• Which condition is most directly associated with elevated carbon dioxide levels during a dive?
• Why is it essential to practice CCR procedures with a buddy and under supervision?
• What is the function of a bailout regulator?
• Which statement correctly lists the three major components of the MK 25 Mod 2?
• Which items should be checked to prevent an electrical fault from compromising CCR safety?
• Which action is the recommended immediate treatment for hypoxia?
• How does depth affect the risk of oxygen toxicity in CCR diving?
• Confusion in divers can be a sign of which of the following?
• Do you have to complete all pre-dive steps in order?
• What is the purpose of the bag breathdown?
• Maintaining a target PPO2 during a CCR dive is intended to minimize the risk of which conditions?
• If the oxygen injection mechanism fails during a CCR dive, how is the situation typically indicated and managed?
• What are the three types of purges?
• Which option best lists the driver's primary responsibilities?
• What is the primary purpose of conducting a purge?
• What are two ways the O2 cylinder can become depleted?
• Why is maintaining PPO2 within a safe range critical during CCR diving?
• Which is NOT a common error when conducting the purge?
• Confusion during a dive can be a sign of which of the following?
• How is maximum operating depth (MOD) determined for a CCR dive?
• What tactical advantage does a CCR provide in combat diving?
• What is the purpose of performing a redundancy check before entering the water in a CCR operation?
• Which action is true regarding recovery after a hypoxia event once on the surface?
• Which device reduces the O2 cylinder pressure to 55-75 psi from the operating range of 10-207 BAR?
• What adds O2 to the breathing bag as required when the breathing bag is emptied on inhalation?
• How does a semi-closed system differ from a fully closed circuit rebreather?
• A headache is the result of which dive injury?
• Why is log-keeping of scrubber usage important?
• What is an emergency ascent protocol on a CCR?
• Which of the following is NOT a purge type?
• What can affect trim, ballast, and rig control?
• Which statement is true about the MK 25 Mod 2?
• How is a CCR dive plan typically organized in terms of gas volumes and depth?
• What is the difference between loop gas and bailout gas?
• In a tactical CCR operation, which statement best describes why stealth is prioritized?
• Which practices help maintain stealth when operating a CCR in a tactical environment?
• Which checks should be performed to ensure bailout gas readiness before a dive?
• Which statement correctly matches the MK 25 UBA's relaxed and high-exercise consumption rates?
• Which two factors affect canister duration?
• Which option is not part of the described O2 flow sequence in the closed-circuit UBA?
• What is a BOV in the context of a CCR, and what does it do?
• High temperatures will affect the CO2 absorbent. Which statement is true?
• What is the single depth limit for 25 fsw?
• If a diver becomes unconscious or incoherent at depth, what should the buddy do first?
• How long do you have to wait on the surface before flying after an O2 dive?
• What is the single depth limit for 30 fsw?
• What does VENTIDC stand for?
• Name two common absorbent materials used in CCR scrubbers.
• What is the primary responsibility of a CCR dive supervisor during combat dives?
• A headache during or after a dive is most consistent with which condition?
• What is a standard post-dive CCR maintenance practice to ensure readiness for the next dive?
• What is the treatment and management of a non convulsive diver with O2 toxicity?
• What does the equipment case of the MK 25 hold?
• What is the primary reason to monitor O2 exposure during a dive?
• What best describes redundancy in CCR gas management?
• Which of the following best describes the additional risks that combat CCR dives introduce compared to recreational CCR dives?
• Low temperatures will affect the CO2 absorbent.
• What is counterlung collapse or crush and why is it a concern?
• What are the two methods of wearing the MK 25?
• Which statement best describes the purpose of the hard ceiling on PPO2 in CCR diving?
• Which of the following could be a plausible contributor to a diver's headache?
• Which statement best describes Paceman's primary responsibilities?
• How many inches below the chin should the Mk 25 UBA be placed?
• Which statement best describes a semi-closed CCR system's gas handling?
• What is the purpose of a safety stop or equivalent precaution on CCR dives?
• What is a primary advantage of CCR in combat diving?
• In MK 25, which statement describes the equipment case's function?
• What must be considered when donning and sizing the SECUMAR vest?
• What is the remedy for a scrubber breakthrough on a CCR dive?
• If a CCR oxygen sensor fails underwater, which action is recommended?
• CNS oxygen toxicity symptoms may present themselves minutes after off gas.
• What is the most severe symptom of CNS oxygen toxicity?
• What is required for all MK 25 dives?
• Can you mix different lot numbers of CO2 scrubbing material into your canister?
• What is the maximum fill pressure in BAR of the O2 cylinder?
• What signaling or communication strategy should you rely on if CCR problems occur?
• Which response is most appropriate when encountering unfamiliar CCR controls underwater?
• Which term describes elevated carbon dioxide in the blood?
• Which component houses the carbon dioxide scrubber canister in the closed-circuit system?
• In a closed-circuit rebreather, what is the role of the diluent gas?
• Which statement about convulsions in divers is true?
• How many CCs of liquid can the moisture trap hold before any water enters the absorbent material?
• Which unit is used to express the maximum oxygen fill pressure?
• What device alerts you to abnormal PPO2 in a CCR dive?
• At 50 fsw, the SECUMAR minimum pressure of 2400 psig provides how many pounds of lift?
• What is the purpose of monitoring PPO2 with a backup gauge?
• What function does the demand valve serve?
• The MK 25 UBA consumption rates are expressed in which unit?
• How long is the CO2 scrubbing material good for once opened?
• Once a MK 25 UBA is set up, how long is its storage life?
• What is the TWE limit for 41-50 fsw?
• Which bottle on the SECUMAR vest is used in emergencies?
• Describe loop integrity and why leaks are dangerous.
• Which of the following is a direct descriptor of hypercapnia?
• What are early signs of CO2 buildup (hypercapnia) in a CCR diver?
• Which statement best describes confusion during a dive?
• What is the single depth limit for 35 fsw?
• Name two common absorbent materials used in CCR scrubbers.
• What are the two categories of O2 exposure limits?
• Which statement best defines PPO2 and explains its significance in a closed-circuit rebreather (CCR) dive?
• What adjustments need to be made for diving at altitude?
• What runs from the pressure reducer/regulator to the demand valve?
• If you detect a sudden drop in loop oxygen despite all indicators being green, what is the recommended action?
• What is the TWE limit for 21-40 fsw?
• What is the maximum working limit of the MK 25 Mod 2 UBA?
• Which step is used to prevent hypoxia?
• In the closed-circuit UBA, which component does O2 encounter first after leaving the cylinder?
• Who can conduct maintenance on the MK 25?
• Which practice helps ensure redundancy during CCR operations?
• Which component is encountered immediately after the inhalation hose in the O2 path?
• What are the two consumption rates of the MK 25 UBA?
• Which depth range has a TWE limit of 15 minutes?
• Which action helps minimize the risk of exposing your position when using a CCR in combat?
• Which depth range corresponds to the TWE limit of 5 minutes?
• Why is gas management critical in CCR operations?
• How many liters of air is contained in the O2 bottle when filled to capacity?
• After the oxygen passes through the carbon dioxide scrubber canister, where does O2 go?
• Which of the following is NOT listed as a symptom of hypercapnia?
• Will there always be signs of a convulsive diver before it occurs?
• Which factor increases the likelihood of CNS O2 toxicity?
• When should you switch to bailout gas during a CCR dive?
• What is the normal working limit of the MK 25 Mod 2 UBA?
• What is the recommended remedy for a valve or solenoid fault in a CCR system?
• What sequence should you follow if the CCR cannot maintain the target PPO2?
• Which statement describes the MK 25 equipment case accurately?
• Which indicator directly reflects scrubber performance while underwater?