The correct approach involves understanding the core principles of buoyancy control and gas management as defined by ISO 24801-2 for autonomous divers. An autonomous diver, as per the standard, is expected to manage their buoyancy effectively throughout the dive, ensuring a stable descent, neutral buoyancy at the target depth, and a controlled ascent. This requires a proactive approach to managing their breathing and the use of their buoyancy control device (BCD). The scenario describes a diver experiencing a gradual loss of buoyancy control, leading to an uncontrolled descent. This indicates a failure in maintaining neutral buoyancy, which is a fundamental skill for an autonomous diver. The most appropriate immediate action, as per best practices and the standard’s emphasis on safety and self-sufficiency, is to arrest the descent by expelling air from the BCD. This action directly counteracts the loss of buoyancy and allows the diver to regain control. Other actions, such as increasing breathing rate, might temporarily affect buoyancy but are not the primary solution for a mechanical or procedural loss of buoyancy control. Ascending to the surface without addressing the root cause of the descent could be dangerous if the issue persists. Attempting to reach the bottom to investigate the cause is contrary to the principle of immediate safety and control. Therefore, the most direct and effective response to an uncontrolled descent is to manage the buoyancy device to stop the descent.

The scenario describes a Level 2 Autonomous Diver who has exceeded their planned bottom time and is ascending. The critical factor here is the potential for decompression sickness (DCS) due to nitrogen off-gassing. ISO 24801-2:2014, specifically in its requirements for autonomous diving, emphasizes the diver’s responsibility for self-management and adherence to dive profiles. A key principle for autonomous divers is to avoid exceeding planned no-decompression limits. When a diver inadvertently exceeds these limits, the immediate and most appropriate action, as per safe diving practices aligned with standards like ISO 24801-2, is to initiate a safety stop. A safety stop, typically at a shallower depth (e.g., 5 meters or 15 feet) for a duration (e.g., 3-5 minutes), helps to slow the rate of nitrogen elimination from tissues, reducing the risk of DCS. Following the safety stop, the diver should then proceed with a controlled ascent to the surface, maintaining a slow ascent rate (typically no faster than 10 meters or 30 feet per minute) to further minimize bubble formation. The diver should also remain hydrated and avoid strenuous activity post-dive. The other options are less appropriate or potentially dangerous. Immediately surfacing without a safety stop increases DCS risk. Performing a decompression stop at a deeper, predetermined depth is for planned decompression dives, not for an accidental overstay within a no-decompression profile. Waiting at the bottom to “catch up” on nitrogen off-gassing is a dangerous misconception and directly contradicts the principles of dive planning and safety. Therefore, the correct course of action is to perform a safety stop.

The scenario describes an autonomous diver (Level 2) who experiences a gradual ascent rate issue due to a malfunctioning buoyancy compensator (BC) inflator. The diver’s depth is 18 meters, and their planned bottom time is 30 minutes. The diver notices a slow, uncontrolled ascent, indicating a problem with their ability to maintain neutral buoyancy. According to ISO 24801-2:2014, an autonomous diver is trained to manage their buoyancy and plan dives independently within defined limits. A key aspect of this training is the ability to handle common equipment malfunctions. In this situation, the diver’s primary responsibility is to regain control of their ascent rate to prevent a rapid ascent, which can lead to decompression sickness or lung overexpansion. The most immediate and effective action to counteract a slow, uncontrolled ascent caused by a BC malfunction is to vent air from the BCD. This reduces the overall buoyancy of the diver, allowing them to descend or at least slow their ascent. While other actions might be considered in different scenarios (e.g., signaling a buddy, aborting the dive), the direct and immediate solution to a buoyancy control problem causing an uncontrolled ascent is to manage the air in the buoyancy control device. The diver’s training emphasizes self-reliance and problem-solving in such situations. Therefore, the most appropriate immediate action is to vent the BCD to regain control.

The core principle tested here relates to the diver’s responsibility for their own safety and the limitations of their training. ISO 24801-2:2014, specifically in its requirements for Level 2 Autonomous Diver, emphasizes that while divers are trained to plan and execute dives independently within defined limits, they are not equipped to handle situations that exceed their training or involve complex rescue scenarios. The standard mandates that autonomous divers operate within their personal experience and training envelope, and crucially, that they understand when to seek assistance from more qualified personnel or emergency services. Therefore, a diver encountering a situation requiring advanced buoyancy control techniques beyond their Level 2 training, or a situation involving a distressed diver requiring immediate rescue and advanced life support, falls outside the scope of their autonomous capabilities. The standard implicitly and explicitly requires divers to recognize their limitations and act accordingly, which includes not attempting tasks for which they have not been trained or certified. This understanding is paramount for maintaining safety and adhering to the principles of responsible recreational diving as outlined in the standard. The scenario presented is designed to assess this critical awareness of personal limitations and the appropriate response when faced with a situation exceeding those boundaries.

The question assesses the understanding of dive planning principles for autonomous divers, specifically concerning the impact of environmental factors on ascent rates and surface intervals, as stipulated by ISO 24801-2:2014. The core concept here is that increased ambient pressure necessitates slower ascent rates to prevent decompression sickness (DCS). While no explicit calculation is required, the underlying principle is that the longer a diver stays at depth, the more nitrogen is absorbed, and the more critical a controlled ascent becomes. A slower ascent rate, as mandated by decompression tables or dive computers, is crucial for the safe off-gassing of nitrogen. Furthermore, the duration of the surface interval directly influences the residual nitrogen in the body. A shorter surface interval means more residual nitrogen, which in turn requires more conservative dive planning for subsequent dives, often involving shallower depths, shorter bottom times, or longer ascent times. Therefore, the most appropriate response acknowledges the need for a slower ascent due to the increased depth and the necessity of a longer surface interval to mitigate residual nitrogen, thereby ensuring safety for the subsequent dive. This aligns with the principles of responsible dive planning for autonomous divers as outlined in the standard, which emphasizes minimizing risk through adherence to established safety protocols.

The core principle of diver autonomy under ISO 24801-2:2014, specifically at Level 2 (Autonomous Diver), emphasizes the diver’s responsibility for their own dive planning and execution within defined limits. This includes managing their air supply, depth, and time to ensure a safe ascent and avoid decompression obligations. A critical aspect of this responsibility is understanding and applying the concept of a “no-decompression limit” (NDCL). The NDCL represents the maximum time a diver can spend at a given depth without requiring mandatory decompression stops on ascent. Exceeding this limit necessitates a decompression schedule, which is beyond the scope of Level 2 autonomous diving as defined by the standard. Therefore, a diver certified to Level 2 must plan their dive to remain within these established limits for the planned depth. For a planned dive to 25 meters, a typical NDCL might be around 20 minutes, though this is dependent on specific dive tables or dive computers used, which are based on established decompression models. The crucial understanding is that the diver must *plan* to stay within this limit, not simply react to exceeding it. The standard mandates that Level 2 divers are competent in planning dives to a maximum depth of 30 meters, and this planning must inherently incorporate adherence to NDCLs. The question tests the understanding of this fundamental planning requirement for autonomous diving.

The question assesses understanding of the principles of dive planning and risk management as outlined in ISO 24801-2:2014, specifically concerning the management of potential decompression obligations for autonomous divers. The core concept here is the conservative application of dive tables or dive computers to ensure safety margins. For an autonomous diver, the primary responsibility for managing their dive profile and avoiding decompression sickness lies with them. ISO 24801-2:2014 emphasizes that Level 2 divers (Autonomous Divers) should be trained to plan and execute dives within no-decompression limits (NDLs) and to manage potential deviations.

Consider a scenario where a diver plans a dive to a maximum depth of 25 meters. Using standard recreational dive tables or a dive computer, the no-decompression limit (NDL) for this depth is determined to be 20 minutes. However, to ensure a greater safety margin and account for potential minor inaccuracies in depth measurement or ascent rate, a prudent diver might choose to limit their bottom time to 15 minutes. This decision is based on the principle of conservatism, which is a cornerstone of safe diving practices and is implicitly supported by the standard’s emphasis on risk mitigation. The remaining 5 minutes of the NDL represent a buffer. This buffer is not a reserve for extending the dive beyond the planned limits but rather a safety margin to account for real-world variables. Therefore, the diver should ascend from their planned bottom time of 15 minutes, arriving at the surface well within the calculated NDL for 25 meters. The concept of a “safety stop” at a shallower depth (e.g., 5 meters) for a specified duration (e.g., 3 minutes) is a common practice, often recommended or required by dive training agencies and dive computers, to further mitigate the risk of decompression sickness, especially after dives approaching NDLs. This safety stop is performed *after* the planned bottom time and *before* the final ascent to the surface. It is not part of the bottom time itself. The diver’s total time underwater, from leaving the surface to reaching the surface, is the total dive time. If the diver spends 15 minutes on the bottom and then performs a 3-minute safety stop, their total time underwater would be 18 minutes. This is still within the 20-minute NDL for 25 meters. The question asks about the *purpose* of the remaining 5 minutes of the NDL. This remaining time is a buffer for unforeseen circumstances or minor deviations, not for extending the planned bottom time. The most appropriate action for the diver, given the 15-minute planned bottom time and the 20-minute NDL, is to ascend from the bottom at the 15-minute mark and perform the safety stop. The remaining 5 minutes of the NDL are essentially a buffer against exceeding the NDL due to minor errors or variations.

The question assesses the understanding of dive planning principles for autonomous divers, specifically concerning the impact of environmental factors on ascent rates and safety margins. ISO 24801-2:2014 emphasizes the diver’s responsibility for planning and executing dives within their training and experience limits, considering all relevant variables. A key aspect of this is understanding how increased ascent rates, often necessitated by unexpected conditions or equipment issues, affect decompression obligations and the potential for decompression sickness (DCS). While a faster ascent might seem efficient, it significantly reduces the time available for off-gassing at shallower depths, thereby increasing the risk of bubble formation. Therefore, a diver encountering a situation requiring a more rapid ascent must adjust their plan to incorporate a longer safety stop or a more conservative ascent profile to mitigate this increased risk. This adjustment is crucial for maintaining a safety margin and adhering to the principles of safe diving as outlined in the standard, which prioritizes diver well-being over speed. The other options represent less effective or potentially dangerous responses. Increasing the surface interval without adjusting the ascent profile does not directly address the increased risk from a faster ascent. Continuing the dive as planned without any modification ignores the altered physiological conditions. A shorter safety stop would directly contradict the need to compensate for a faster ascent.

The core principle being tested here relates to the diver’s responsibility for managing their ascent rate to avoid decompression sickness (DCS) and lung overexpansion injuries, as stipulated by ISO 24801-2:2014. Specifically, the standard emphasizes controlled ascents. A controlled ascent rate is generally understood to be no faster than 10 meters per minute (approximately 30 feet per minute). Exceeding this rate significantly increases the risk of nitrogen bubbles forming in the tissues, leading to DCS. Conversely, an ascent rate that is too slow, while generally safe from a pressure perspective, can lead to excessive gas consumption and potentially extend bottom time beyond planned limits, which is also a factor in dive planning and safety. Therefore, maintaining a rate that is both safe and efficient is paramount. The scenario describes a diver ascending from a depth of 20 meters. To ascend at a rate of 10 meters per minute, it would take 2 minutes to reach the surface from 20 meters (20 meters / 10 meters/minute = 2 minutes). This is the benchmark for a safe ascent. The question asks for the most appropriate action given a specific ascent scenario. The correct approach involves adhering to the recommended ascent rate to mitigate physiological risks.

The core principle being tested here is the diver’s responsibility for managing their air supply and ascent profile, as dictated by the principles of autonomous diving under ISO 24801-2. Specifically, the standard emphasizes that an autonomous diver must plan and execute dives within their training and experience limits, including managing their breathing gas. The scenario describes a diver who has exceeded their planned bottom time and is now at a depth where their remaining air, combined with the ascent rate and potential safety stops, would lead to a critical situation.

To determine the correct action, one must consider the diver’s current state and the implications of different choices. The diver has 50 bar of air remaining and is at a depth of 20 meters. A standard ascent rate is typically 10 meters per minute. To reach the surface from 20 meters, it takes 2 minutes of ascent. If a safety stop is required, for example, at 5 meters for 3 minutes, this adds to the total time at depth and the air consumed during ascent.

Let’s analyze the air consumption. Assuming a surface air consumption (SAC) rate of 20 liters per minute (a common reference point, though individual rates vary), and a breathing rate of 15 liters per minute at 20 meters (due to increased density, approximately 1.5 times the surface rate: \(15 \text{ L/min} \times 1.5 = 22.5 \text{ L/min}\) absolute volume, or \(22.5 / 3 = 7.5 \text{ L/min}\) equivalent surface volume). However, the question provides the remaining air in bar, which is a more direct measure. A typical cylinder might be 10-12 liters. If the diver has 50 bar remaining in a 10-liter cylinder, that’s \(50 \text{ bar} \times 10 \text{ L/bar} = 500 \text{ L}\) of air at surface equivalent.

The critical factor is the time it will take to ascend safely. Ascending from 20 meters at 10 meters per minute takes 2 minutes. If a safety stop at 5 meters for 3 minutes is necessary, this adds 3 minutes to the time spent underwater. During the ascent, air is consumed. A conservative estimate for air consumption during ascent from 20 meters might be around 10-15 L/min (equivalent surface volume). Over a 2-minute ascent, this would be 20-30 L. If a safety stop is included, the consumption increases.

The scenario implies that the current air supply is insufficient for a safe ascent with a potential safety stop. Therefore, the most prudent action, aligning with autonomous diving principles and safety regulations, is to immediately initiate a controlled ascent. This involves ascending at the prescribed rate and performing any necessary safety stops based on the dive profile and remaining air. The key is to prioritize reaching the surface safely. The diver must manage their ascent to ensure they have sufficient air to complete the journey and any required decompression or safety stops. The situation described necessitates an immediate, controlled ascent to conserve air and reach the surface within safe limits. This approach directly addresses the potential for an out-of-air emergency by proactively managing the remaining gas and ascent profile.

The core principle tested here relates to the diver’s responsibility for managing their ascent rate to avoid decompression sickness, a critical aspect of autonomous diving as defined by ISO 24801-2. The standard emphasizes that divers must ascend at a controlled rate, typically not exceeding \(10\) meters per minute. This is to allow dissolved inert gases (primarily nitrogen) in the body tissues to be released safely through respiration, preventing the formation of bubbles that can cause decompression sickness. A rapid ascent can lead to supersaturation of tissues with nitrogen, overwhelming the body’s ability to off-gas, thus increasing the risk of symptoms ranging from joint pain to paralysis or even death. Therefore, understanding and adhering to a safe ascent rate is paramount for the autonomous diver’s safety and is a direct application of the training principles outlined in the standard. The other options represent either unsafe practices, misinterpretations of decompression theory, or actions that do not directly address the primary risk of rapid ascent. For instance, maintaining a constant depth is contrary to the need to ascend, and ascending at a faster rate than recommended significantly elevates risk. While monitoring air supply is crucial, it doesn’t directly address the physiological consequences of ascent speed.

The core principle being tested here is the diver’s responsibility for managing their ascent rate to avoid decompression sickness, a critical safety aspect for autonomous divers as defined in ISO 24801-2. The standard mandates that divers maintain an ascent rate that prevents the formation of nitrogen bubbles within the body’s tissues. While specific ascent rates can vary based on depth and dive profile, a commonly accepted safe ascent rate, often taught and reinforced in diver training programs aligned with standards like ISO 24801-2, is no faster than 18 meters (60 feet) per minute. This rate allows dissolved nitrogen to off-gas gradually through the lungs, minimizing the risk of decompression issues. Therefore, a diver ascending from a depth of 25 meters and reaching the surface in 1 minute and 20 seconds is ascending at a rate of \( \frac{25 \text{ meters}}{80 \text{ seconds}} \times \frac{60 \text{ seconds}}{1 \text{ minute}} = 18.75 \) meters per minute. This rate slightly exceeds the recommended maximum of 18 meters per minute, indicating a potential for increased risk. The explanation should focus on the physiological reasons behind controlled ascent rates, the concept of nitrogen off-gassing, and the consequences of rapid ascents, such as decompression sickness (DCS), which can manifest in various forms from joint pain to neurological impairment. The explanation must emphasize that adherence to safe ascent rates is a fundamental responsibility of an autonomous diver, directly linked to their training and the safety protocols outlined in standards like ISO 24801-2. It should also touch upon the role of dive computers and dive tables in monitoring ascent rates and planning dives to remain within safe limits, reinforcing the diver’s self-reliance and decision-making capabilities.

The scenario describes a Level 2 Autonomous Diver who has exceeded their planned bottom time and is ascending from a dive. The critical factor in this situation is the potential for decompression sickness (DCS). ISO 24801-2:2014, Part 2, specifically addresses the training requirements for autonomous divers, emphasizing safe ascent rates and the avoidance of decompression obligations. While the diver is not explicitly stated to have violated ascent rate rules, exceeding planned bottom time without a safety stop or with a faster-than-recommended ascent could lead to bubble formation. The primary risk here is DCS, which can manifest in various ways. Therefore, the most appropriate immediate action, as per safe diving practices and the principles of dive planning and execution outlined in standards like ISO 24801-2, is to seek medical evaluation. This evaluation is crucial to rule out or treat any potential physiological effects of the dive, even if symptoms are not immediately apparent. The other options are less critical or potentially harmful. Continuing to dive without assessment could exacerbate an underlying issue. Performing a deep dive is counterproductive and dangerous. Ignoring the situation is negligent. The core principle is to prioritize the diver’s physiological well-being after a dive that deviated from the plan, especially concerning time at depth.

The core principle being tested here is the diver’s responsibility for managing their ascent rate to avoid decompression sickness (DCS) and lung overexpansion injuries, as stipulated by ISO 24801-2:2014. The standard emphasizes that autonomous divers are responsible for their own dive planning and execution, including adherence to ascent profiles. A controlled ascent rate is paramount. While a slower ascent is generally safer, an excessively slow ascent can lead to other physiological issues or simply be inefficient. Conversely, a rapid ascent significantly increases the risk of DCS due to the rapid off-gassing of inert gases under decreasing ambient pressure. The standard implicitly requires divers to monitor their depth and time to manage their ascent, ensuring it remains within safe physiological limits, typically guided by dive computer algorithms or dive tables. The concept of “controlled ascent” implies a deliberate and managed process, not a passive drift or a rushed exit from the water. Therefore, maintaining a consistent and safe ascent rate, as dictated by the dive computer or established dive planning principles, is the most critical factor in preventing ascent-related injuries. This involves active monitoring and adjustment by the diver.

The scenario describes a diver experiencing symptoms consistent with decompression sickness (DCS). ISO 24801-2:2014, specifically in its emphasis on diver responsibility and emergency procedures, mandates that divers recognize and respond to potential dive-related illnesses. Level 2 Autonomous Diver training requires an understanding of basic first aid for diving injuries and the importance of seeking professional medical attention. The primary and immediate action for a suspected case of DCS is to administer emergency oxygen and seek professional medical evaluation. While re-immersion in a hyperbaric chamber is the definitive treatment, it is administered by medical professionals. Providing surface oxygen is a critical first aid step to improve tissue oxygenation and potentially mitigate the progression of DCS symptoms while awaiting professional medical help. Therefore, administering emergency oxygen and contacting emergency medical services are the most appropriate initial actions for an autonomous diver to take.

The core principle being tested here is the diver’s responsibility for managing their ascent rate to avoid decompression sickness (DCS) and lung overexpansion injuries, as stipulated by ISO 24801-2:2014. The standard emphasizes that autonomous divers are responsible for their own dive planning and execution, including adherence to ascent profiles. A controlled ascent rate is paramount. Exceeding a safe ascent rate, typically considered to be \(9\) meters per minute (\(30\) feet per minute), significantly increases the risk of bubble formation within the body’s tissues, leading to DCS. Conversely, an ascent rate that is too slow, while not directly causing injury, can lead to unnecessary nitrogen absorption and potentially longer decompression obligations if the dive profile warrants it, though the immediate danger is less acute than a rapid ascent. The concept of “controlled ascent” implies maintaining a rate that allows for the safe off-gassing of nitrogen and prevents the formation of gas bubbles. Therefore, the most critical factor for an autonomous diver to manage during ascent, in relation to safety and adherence to the standard’s principles, is the rate at which they ascend. This directly relates to the diver’s ability to manage their physiological response to pressure changes.

The scenario describes a Level 2 Autonomous Diver who has exceeded their planned bottom time due to an unexpected encounter with marine life. The diver has 50 bar of air remaining in their tank and is at a depth of 25 meters. The planned dive profile was 20 minutes at 25 meters, with a surface interval of 1 hour and 30 minutes before the next dive. The diver’s current air consumption rate is 20 liters per minute.

First, calculate the remaining air in liters:
Tank capacity = 200 bar (standard assumption for a 12-liter tank, though not explicitly stated, this is a common baseline for such problems. If a different tank size were intended, it would need to be specified. For the purpose of demonstrating the concept, we use 12L).
Remaining air = 50 bar * 12 L/bar = 600 L

Next, determine the minimum air required for ascent and safety stop. A standard ascent rate is 10 meters per minute. For a 25-meter dive, a 3-minute ascent would be typical. A safety stop of 5 minutes at 5 meters is also a common practice for dives of this depth and duration.

Air required for ascent (3 minutes at 25m):
At 25 meters, the ambient pressure is 3.5 ATA (1 ATA at surface + 2 ATA from depth).
Air consumption during ascent = Ascent time * Ascent depth * Air consumption rate * (1 + Depth/10)
This formula is incorrect for calculating air consumption during ascent as it doesn’t account for the changing pressure. A more accurate approach is to consider the total volume of air needed to ascend from the deepest point to the surface, accounting for the expansion of air.

Let’s re-evaluate the air requirement for ascent and safety stop based on the standard practice for Level 2 Autonomous Divers as per ISO 24801-2:2014. The standard emphasizes conservative practices. A common guideline is to reserve a minimum of 50 bar for emergencies and ascent. However, the question asks for the *minimum* air required for the ascent and safety stop based on the current situation and consumption rate.

Let’s assume a standard ascent profile:
Ascent time from 25m to surface: 3 minutes (at 10m/min).
During ascent, the pressure decreases. The air consumed is at the ambient pressure.
Air consumed during ascent = (Volume at surface pressure)
A simpler, more practical approach for diver training is to consider the volume of air needed to reach the surface and perform a safety stop. For a 25m dive, a 3-minute ascent and a 5-minute safety stop at 5m are common.

Air needed for ascent:
From 25m to 5m (20m distance): 2 minutes ascent.
From 5m to surface (5m distance): 1 minute ascent.
Total ascent time = 3 minutes.

Air consumption during ascent is complex due to pressure changes. However, a practical approach for training is to estimate the air needed to reach the surface and perform a safety stop. A common guideline is to reserve a minimum of 50 bar for ascent and reserve.

Let’s calculate the air consumed for the planned dive duration so far. If the planned dive was 20 minutes at 25 meters, and the diver has encountered marine life, they have likely exceeded this. The question implies they are *currently* at 25 meters with 50 bar remaining.

The core of the question is about the diver’s ability to safely ascend and perform a safety stop with the remaining air. ISO 24801-2:2014 emphasizes conservative air management. A key principle is to always have enough air to reach the surface and perform a safety stop.

Let’s consider the air needed for a safety stop at 5 meters for 5 minutes.
At 5 meters, the ambient pressure is 1.5 ATA.
Air consumed during safety stop = Safety stop duration * Safety stop depth pressure * Air consumption rate
Air consumed during safety stop = 5 minutes * 1.5 ATA * 20 L/min = 150 L

Now, consider the air needed to ascend from 25 meters to 5 meters. This is a 20-meter ascent. A 10 m/min ascent rate means 2 minutes.
During this ascent, the pressure changes from 3.5 ATA to 1.5 ATA.
A simplified way to think about air consumption during ascent is that the volume of air delivered by the regulator is proportional to the ambient pressure. So, to ascend 20 meters (taking 2 minutes), the air consumed is roughly equivalent to 2 minutes at the average pressure or the starting pressure.

A more practical approach for Level 2 divers is to ensure they have a sufficient reserve. The standard requires divers to monitor their air supply and plan ascents conservatively. A common rule of thumb is to reserve at least 50 bar for ascent and emergencies.

Let’s calculate the air consumed for the dive *up to this point*. If the diver planned for 20 minutes at 25m and has encountered marine life, they might have been down longer. However, the question states they have 50 bar *remaining*. This implies the calculation should focus on what is needed *from this point*.

Air needed for ascent from 25m to surface (3 minutes):
This is approximately 3 minutes of breathing at the surface equivalent.
Air consumed for ascent = 3 minutes * 20 L/min = 60 L (This is a simplification, as consumption is higher at depth).

A more accurate calculation for ascent:
Air needed to ascend from 25m to 5m (2 minutes):
At 25m (3.5 ATA), consumption is 20 L/min.
At 5m (1.5 ATA), consumption is 20 L/min.
The total volume of air delivered during ascent is what matters.

Let’s use a standard guideline for calculating air needed for ascent and safety stop. For a 25m dive, a common requirement is to have enough air for a 3-minute ascent and a 5-minute safety stop at 5m.
Air for 3-minute ascent: At 25m, this would be roughly 3 minutes * 20 L/min * 3.5 ATA = 210 L (This is an overestimation as pressure decreases).
A more conservative approach is to consider the volume of air at surface pressure.
Air for ascent (3 minutes at 20 L/min) = 60 L.
Air for safety stop (5 minutes at 5m, 1.5 ATA, at 20 L/min) = 5 min * 1.5 ATA * 20 L/min = 150 L.
Total air needed for ascent and safety stop = 60 L + 150 L = 210 L.

The diver has 50 bar * 12 L/bar = 600 L of air remaining.
If 210 L is needed for ascent and safety stop, the diver has 600 L – 210 L = 390 L remaining for the ascent and safety stop. This is sufficient.

However, the question is about the *minimum* air required for a safe ascent and safety stop, and what the diver *should* do. ISO 24801-2:2014 emphasizes having a reserve. A common reserve is 50 bar.

Let’s re-interpret the question: What is the *minimum* air required to safely ascend from 25 meters and perform a standard 5-minute safety stop at 5 meters, given a consumption rate of 20 L/min?

Ascent from 25m to 5m (2 minutes):
Air consumed = 2 minutes * 20 L/min = 40 L (This is the volume at surface pressure if we consider the rate as surface equivalent).
A more accurate calculation considers the pressure.
Air consumed during ascent from 25m to 5m:
This is best approximated by considering the total volume of air delivered.
A common method is to use the surface equivalent volume.
Ascent from 25m to 5m (2 minutes at 10m/min):
The air delivered during this ascent is roughly equivalent to 2 minutes of breathing at the surface rate, plus the air for the safety stop.

Let’s focus on the air needed for the safety stop at 5 meters for 5 minutes.
At 5 meters, the ambient pressure is 1.5 ATA.
Air consumption for safety stop = 5 minutes * 1.5 ATA * 20 L/min = 150 L.

Now, for the ascent from 25 meters to 5 meters. This takes 2 minutes.
The air consumed during this ascent is best considered as the volume at surface pressure.
Air consumed during ascent = 2 minutes * 20 L/min = 40 L.

Total minimum air required for ascent and safety stop = Air for ascent + Air for safety stop
Total minimum air required = 40 L + 150 L = 190 L.

The diver has 600 L remaining. This is ample. The question asks for the minimum air required for a safe ascent and safety stop. The critical factor is the safety stop at 5 meters.

The correct approach is to calculate the air needed for the safety stop and the ascent.
Safety stop at 5m for 5 minutes:
Pressure at 5m = 1.5 ATA.
Air consumption = 5 min * 1.5 ATA * 20 L/min = 150 L.

Ascent from 25m to 5m:
This takes 2 minutes (assuming 10m/min ascent rate).
The air consumed during ascent is best represented by its surface equivalent volume.
Air consumption during ascent = 2 min * 20 L/min = 40 L.

Total minimum air required for a safe ascent and safety stop = 150 L (safety stop) + 40 L (ascent) = 190 L.

The diver has 50 bar * 12 L/bar = 600 L. This is sufficient. The question is asking for the minimum air required for the ascent and safety stop.

The correct answer is the total volume of air needed for the safety stop and the ascent, calculated based on the depth, duration, and consumption rate.

Calculation:
Air for safety stop at 5m for 5 minutes: \(5 \text{ min} \times 1.5 \text{ ATA} \times 20 \text{ L/min} = 150 \text{ L}\)
Air for ascent from 25m to 5m (2 minutes at 10m/min): \(2 \text{ min} \times 20 \text{ L/min} = 40 \text{ L}\)
Total minimum air required = \(150 \text{ L} + 40 \text{ L} = 190 \text{ L}\)

This calculation represents the minimum volume of air, at surface pressure equivalent, that must be available to complete the ascent and safety stop. It is crucial for Level 2 Autonomous Divers to understand these calculations to manage their air supply effectively and ensure they always have enough air to reach the surface safely, adhering to the principles outlined in ISO 24801-2:2014 regarding dive planning and air management. This includes accounting for the increased air consumption at depth and the need for a safety stop. The standard emphasizes conservative practices, meaning divers should always aim to have a greater reserve than this calculated minimum.

The scenario describes a Level 2 Autonomous Diver who has planned a dive to a maximum depth of 25 meters. The diver intends to use a single cylinder with a usable volume of 15 liters, filled to a pressure of 200 bar. The diver’s surface air consumption rate (SAC rate) is established at 20 liters per minute. The planned bottom time is 30 minutes. To determine the remaining air at the surface equivalent, we first calculate the total air consumed in terms of surface volume.

The pressure at 25 meters is approximately 3.5 ATA (Atmospheres Absolute), calculated as 1 ATA (surface pressure) + (25 meters / 10 meters per ATA).

The volume of air consumed at depth is the SAC rate multiplied by the pressure at depth. So, the air consumption at 25 meters is \(20 \text{ L/min} \times 3.5 \text{ ATA} = 70 \text{ L/min}\) (surface equivalent).

The total air consumed during the 30-minute bottom time is the consumption rate at depth multiplied by the time: \(70 \text{ L/min} \times 30 \text{ min} = 2100 \text{ L}\) (surface equivalent).

The total usable air in the cylinder at the start of the dive is the cylinder volume multiplied by the initial fill pressure: \(15 \text{ L} \times 200 \text{ bar} = 3000 \text{ L}\) (surface equivalent, assuming 1 bar ≈ 1 ATA for simplicity in this context of volume calculation).

The remaining air at the surface equivalent is the initial total usable air minus the total air consumed: \(3000 \text{ L} – 2100 \text{ L} = 900 \text{ L}\) (surface equivalent).

This remaining air of 900 liters at surface equivalent is crucial for the diver’s safety margin and ascent. ISO 24801-2:2014 emphasizes the importance of conservative dive planning, including maintaining an adequate reserve of breathing gas. This reserve is typically calculated as a specific volume or pressure that should be left in the cylinder upon reaching the surface, or a minimum pressure to be maintained at a safety stop or before ascending. The calculated 900 liters represents the air available for the ascent and any contingency, ensuring the diver adheres to safe ascent rates and potentially performs a safety stop. This calculation directly relates to the diver’s ability to manage their gas supply autonomously and safely, a core competency for Level 2 divers. The standard mandates that divers must be able to plan and execute dives within their training limits, which includes accurate gas consumption calculations and adherence to established safety margins.

The core principle being tested here is the diver’s responsibility for their own dive plan and execution, a fundamental aspect of autonomous diving as defined in ISO 24801-2:2014. The standard emphasizes that a Level 2 diver, an autonomous diver, is competent to plan and execute dives independently within their certification limits. This includes managing their air supply, depth, time, and ascent rates, as well as responding to common in-water problems. The scenario describes a situation where a buddy diver experiences a minor equipment issue (a slightly leaking mask seal) that, while requiring attention, does not necessitate an immediate emergency ascent or a significant deviation from the planned dive profile for the autonomous diver. The autonomous diver’s primary responsibility is to ensure their own safety and the safety of their buddy through appropriate monitoring and decision-making. In this context, the most appropriate action for the autonomous diver is to assess the situation, communicate with their buddy, and if the leak is manageable and does not compromise the buddy’s safety or the dive plan significantly, continue the dive while monitoring the situation closely. This demonstrates the autonomous diver’s ability to manage minor contingencies without resorting to drastic measures. The other options represent either an overreaction to a minor issue or a failure to adequately manage the situation. An immediate emergency ascent for a minor mask leak would be an unnecessary risk and a failure to apply appropriate judgment. Continuing the dive without acknowledging or addressing the buddy’s issue, even if minor, would be a lapse in buddy responsibility. Attempting complex repairs underwater without proper training or in a situation that compromises safety would also be inappropriate. Therefore, the correct approach involves a calm assessment, communication, and a decision based on the overall safety and the dive plan.

The question assesses the understanding of dive planning principles for autonomous divers under ISO 24801-2:2014, specifically concerning the management of ascent rates and the implications for residual nitrogen. The scenario describes a dive to a maximum depth of 25 meters for 30 minutes. Using a standard dive table or dive computer algorithm (which is implicitly assumed for this level of training), we need to determine the minimum surface interval required to avoid decompression obligations on a subsequent dive, assuming the first dive was conducted with no planned decompression stops.

For a dive to 25 meters (approximately 82 feet) for 30 minutes, a typical dive computer or table would assign a “No-Decompression Limit” (NDL) or a “Group Designation” that reflects the residual nitrogen. Let’s assume, for illustrative purposes, that this dive results in a Group Designation of ‘G’ at the surface, indicating a significant amount of residual nitrogen. To return to Group Designation ‘A’ (meaning no residual nitrogen from the previous dive), a diver typically needs a surface interval that allows for sufficient off-gassing.

The standard rule of thumb for calculating surface intervals to eliminate residual nitrogen is that for every minute spent at depth, a certain amount of surface interval is required. While specific tables and algorithms vary, a common guideline is that a surface interval of at least twice the bottom time is often needed to significantly reduce residual nitrogen. In this case, with a 30-minute bottom time, a surface interval of 60 minutes would be a reasonable starting point to aim for returning to a state of no residual nitrogen. This allows the body to off-gas the absorbed nitrogen.

Therefore, the minimum surface interval required to ensure no decompression obligations on a subsequent dive, based on the principles of nitrogen absorption and off-gassing as outlined in standards like ISO 24801-2, is approximately 60 minutes. This ensures that the diver’s physiological state is reset to a baseline before commencing another dive, thereby avoiding the need for mandatory decompression stops. This principle is fundamental to safe recreational diving practices and is a core competency for autonomous divers.

The scenario describes a Level 2 Autonomous Diver who has planned a dive to a maximum depth of 25 meters. They are using a dive computer that indicates a remaining bottom time (RBT) of 15 minutes at this depth. The diver’s planned ascent rate is 10 meters per minute. According to the principles of dive planning and decompression theory as outlined in standards like ISO 24801-2, a safety stop is a crucial component of a safe ascent. While the specific duration and depth of a safety stop can vary based on dive profile and local regulations, a common practice for dives approaching the no-decompression limit (NDL) is a safety stop at 5 meters. Given the planned ascent rate, reaching 5 meters from a depth of 25 meters would take \( \frac{25 \text{ m} – 5 \text{ m}}{10 \text{ m/min}} = \frac{20 \text{ m}}{10 \text{ m/min}} = 2 \text{ minutes} \). A standard safety stop duration is often 3 to 5 minutes. Therefore, the total time spent from the bottom at 25 meters, including the ascent to the safety stop depth and the safety stop itself, would be approximately 2 minutes (ascent) + 3-5 minutes (safety stop) = 5-7 minutes. This duration must be accounted for within the diver’s overall dive time and nitrogen loading. The question tests the understanding of ascent rates, safety stop procedures, and their integration into dive planning for an autonomous diver, emphasizing the practical application of dive theory to ensure safety margins are maintained. The core concept is that the planned bottom time must accommodate the ascent and any required safety procedures, ensuring the diver does not exceed their no-decompression limits or compromise their safety.

The scenario describes a Level 2 Autonomous Diver who has exceeded their planned bottom time and is experiencing symptoms consistent with nitrogen narcosis. The diver’s planned dive profile was 30 meters for 20 minutes, with a surface interval of 1 hour. Upon reaching 30 meters, the diver continued for an additional 10 minutes, making the total bottom time 30 minutes at this depth. This deviation from the plan necessitates a re-evaluation of the decompression obligations according to the dive computer’s algorithm or a recognized dive table.

For a theoretical calculation using a standard no-decompression limit (NDL) table, a 30-meter dive typically has an NDL of 20 minutes. Exceeding this by 10 minutes means the diver has entered a decompression obligation. The dive computer would have calculated the required ascent rate and safety stops based on the actual dive profile. Without the specific dive computer algorithm or table, we can infer the principle. The diver’s symptoms (disorientation, impaired judgment) are indicative of nitrogen narcosis, which is exacerbated by longer bottom times and deeper depths. The critical action for the diver is to ascend immediately and safely, managing any required decompression stops. The question tests the understanding of exceeding NDL and the immediate management of such a situation, which involves prioritizing safety and adhering to decompression protocols. The correct response focuses on the immediate actions required to mitigate the risk of decompression sickness and the effects of narcosis, which is to ascend and perform necessary decompression.

The core principle tested here relates to the diver’s responsibility for managing their ascent rate to avoid decompression sickness (DCS). ISO 24801-2:2014, specifically in the context of autonomous diving (Level 2), emphasizes the diver’s self-reliance and understanding of dive physics and physiology. A controlled ascent rate is paramount. While a slower ascent is generally safer, exceeding a specified rate significantly increases the risk of bubble formation in tissues and the bloodstream. The standard implicitly or explicitly guides divers to maintain an ascent rate that allows for gradual off-gassing of inert gases. A rate of 10 meters per minute (approximately 30 feet per minute) is a widely accepted safe ascent rate in recreational diving, designed to minimize the risk of DCS. Ascending faster than this rate, such as at 15 meters per minute, compromises the body’s ability to safely expel dissolved nitrogen. Conversely, an ascent rate of 5 meters per minute, while safe, is unnecessarily slow and can lead to increased oxygen consumption and potential issues with buddy separation or air supply management over longer dives. Therefore, adhering to the recommended maximum ascent rate is a critical safety protocol for autonomous divers.

The core principle being tested here is the diver’s responsibility for managing their ascent rate to prevent decompression sickness (DCS). ISO 24801-2:2014, specifically in its requirements for autonomous divers (Level 2), emphasizes the diver’s self-reliance and understanding of dive planning and execution. A critical aspect of this is adhering to safe ascent rates. While specific dive computers and dive tables might suggest various ascent rates, the standard mandates a maximum ascent rate to mitigate the risk of bubble formation and tissue damage. A commonly accepted and safe maximum ascent rate in recreational diving, as reflected in training standards and often implemented in dive computers and dive tables, is 10 meters per minute (or approximately 30 feet per minute). This rate allows dissolved nitrogen to off-gas gradually and safely through the lungs. Exceeding this rate significantly increases the risk of DCS symptoms, ranging from joint pain to more severe neurological issues. Therefore, a diver planning a dive to a maximum depth of 25 meters and intending to ascend directly to the surface without any decompression stops would need to ensure their ascent does not exceed this critical rate. The question assesses the understanding of this fundamental safety parameter.

The core principle tested here relates to the diver’s responsibility for their own safety and the critical importance of pre-dive planning, particularly concerning air consumption and ascent profiles, as outlined in ISO 24801-2:2014 for autonomous divers. The standard emphasizes that an autonomous diver must be capable of planning and executing dives independently, which includes managing their breathing gas and ensuring a safe ascent. A key aspect of this is understanding the concept of remaining air and its relationship to the planned bottom time and ascent. While no specific calculation is required to arrive at the answer, the underlying concept is that the diver must have sufficient air for the entire dive, including a safety margin and the ascent. The scenario highlights a potential deviation from the planned ascent rate. A safe ascent rate, typically a maximum of \(10\) meters per minute, is crucial to prevent decompression sickness. If a diver ascends too quickly, they risk nitrogen bubbles forming in their tissues. The question probes the diver’s understanding of their responsibility to monitor their air supply and ascent rate, and to take corrective action if deviations occur. The correct approach involves recognizing that the diver’s primary duty is to manage their own dive profile and air consumption, and to abort or modify the dive if conditions or their own state necessitate it, without solely relying on a buddy or instructor for critical safety decisions during an autonomous dive. This aligns with the standard’s focus on self-sufficiency and responsible decision-making.

The scenario describes a Level 2 Autonomous Diver who has completed their training and is now planning a dive. The critical element here is understanding the diver’s responsibilities and the limitations imposed by their certification level as defined by ISO 24801-2:2014. This standard specifies that a Level 2 Autonomous Diver is trained to dive autonomously in familiar environments, within the limits of their training and experience, and typically to depths not exceeding 30 meters (or as specified by their training organization). The key is that they are expected to plan and execute dives independently but within defined parameters. The scenario involves a planned dive to 25 meters, which falls within the general depth limit for this level. The diver is also checking their equipment and considering environmental factors. The question probes the diver’s adherence to the principles of autonomous diving as outlined in the standard. The correct approach involves recognizing that a Level 2 Autonomous Diver is expected to plan and execute dives independently, provided they stay within their training limits and the prevailing environmental conditions are manageable. This includes self-sufficiency in managing dive profiles, gas supply, and potential minor issues. The standard emphasizes the diver’s responsibility for their own safety and the safety of their buddy, if diving with one, within the scope of their training. Therefore, the diver’s actions of planning, checking equipment, and considering environmental factors are all consistent with the expectations of a Level 2 Autonomous Diver.

The question pertains to the critical safety aspect of dive planning and execution for autonomous divers as defined by ISO 24801-2:2014. Specifically, it addresses the management of gas supply and the implications of exceeding planned depth or time, which directly impacts the diver’s remaining gas and potential for decompression obligations. The core principle being tested is the diver’s responsibility to monitor their gas supply and adhere to planned parameters to ensure a safe ascent and avoid decompression sickness.

Consider a Level 2 Autonomous Diver planning a dive to a maximum depth of 30 meters with a planned bottom time of 25 minutes. The diver is using a single cylinder with a starting pressure of 200 bar and a usable volume of 12 liters. The diver’s surface air consumption rate (SAC rate) is determined to be 15 liters per minute. The diver must also account for the “rule of thirds” for gas management, which dictates that one-third of the gas supply is used for the outbound journey, one-third for the return journey, and one-third is reserved for emergencies.

First, calculate the total gas volume available:
Total Volume = Cylinder Pressure × Cylinder Volume
Total Volume = 200 bar × 12 L = 2400 L

Next, determine the gas required for the planned dive based on the SAC rate and depth. The SAC rate needs to be adjusted for ambient pressure. At 30 meters, the ambient pressure is approximately 4 ATA (1 ATA at surface + 3 ATA from depth).
Adjusted SAC Rate = SAC Rate × (Ambient Pressure / 1 ATA)
Adjusted SAC Rate = 15 L/min × (4 ATA / 1 ATA) = 60 L/min

Gas consumed during planned bottom time:
Gas Consumed = Adjusted SAC Rate × Planned Bottom Time
Gas Consumed = 60 L/min × 25 min = 1500 L

Now, apply the rule of thirds to determine the total gas required for the entire dive, including ascent and reserve. The rule of thirds suggests that the total gas used should not exceed two-thirds of the available gas, with one-third reserved. Therefore, the usable gas for the planned dive and ascent is two-thirds of the total volume.
Usable Gas for Dive and Ascent = Total Volume × (2/3)
Usable Gas for Dive and Ascent = 2400 L × (2/3) = 1600 L

The gas required for the planned dive is 1500 L. This leaves 100 L of gas for the ascent and any minor variations.

However, if the diver deviates from the plan and stays at 30 meters for 35 minutes instead of 25 minutes, the gas consumption would increase.
Gas Consumed (35 min) = Adjusted SAC Rate × 35 min
Gas Consumed (35 min) = 60 L/min × 35 min = 2100 L

This 2100 L consumption exceeds the usable gas for the dive and ascent (1600 L) and even the total available gas (2400 L) when considering the rule of thirds for the entire dive. The diver would have only 300 L remaining (2400 L – 2100 L), which is insufficient for a safe ascent and reserve according to the rule of thirds. This scenario highlights the critical importance of adhering to planned dive profiles and managing gas reserves diligently. The diver would need to ascend immediately to remain within safe gas limits.

The correct approach is to recognize that exceeding the planned bottom time significantly depletes the gas supply, potentially compromising safety margins. The diver must ascend immediately when the gas remaining is insufficient for a safe ascent and reserve, as dictated by the rule of thirds and the diver’s specific gas consumption rate. The remaining gas of 300 L is not enough to safely complete the ascent and maintain the one-third reserve. Therefore, the diver must initiate an immediate ascent.

The question assesses the understanding of dive planning principles for autonomous divers as outlined in ISO 24801-2:2014, specifically concerning the management of gas reserves and the implications of ascent rates. The scenario involves a planned dive to a maximum depth of 25 meters with a planned bottom time of 30 minutes. The diver’s air consumption rate is established at 15 liters per minute at the surface. To determine the minimum surface air equivalent (SAE) required for the dive, we first calculate the ambient pressure at the maximum depth. Pressure increases by 1 atmosphere (atm) for every 10 meters of depth in seawater. Therefore, at 25 meters, the ambient pressure is \(1 + \frac{25}{10} = 1 + 2.5 = 3.5\) atm.

The air consumption rate at depth is the surface consumption rate multiplied by the ambient pressure. So, the consumption rate at 25 meters is \(15 \, \text{L/min} \times 3.5 = 52.5 \, \text{L/min}\). The total volume of air consumed during the planned bottom time of 30 minutes is \(52.5 \, \text{L/min} \times 30 \, \text{min} = 1575 \, \text{L}\). This is the volume of air at ambient pressure.

To convert this to Surface Air Equivalent (SAE), we multiply the volume at depth by the ambient pressure: \(1575 \, \text{L} \times 3.5 = 5512.5 \, \text{L}\). This represents the total volume of air that would be consumed if the entire dive were conducted at surface pressure.

ISO 24801-2:2014 emphasizes conservative dive planning, including maintaining adequate gas reserves. A common guideline for autonomous divers is to reserve a minimum of 50 bar (or approximately 50 liters of air at surface pressure, assuming a standard tank) for emergencies and the ascent. This reserve is crucial for managing unexpected situations, such as equipment malfunctions, navigation difficulties, or the need for a slower-than-planned ascent. Therefore, the total gas supply required at the surface should account for the planned consumption plus this safety reserve. The question asks for the minimum total surface air equivalent needed. While the calculation of planned consumption is 5512.5 L SAE, the critical aspect for an autonomous diver is ensuring sufficient reserve. The standard practice, often codified in training standards aligned with ISO 24801-2, is to ensure a reserve equivalent to the planned consumption or a significant portion thereof, often at least 50 bar of pressure remaining in the cylinder, which translates to a substantial volume at surface pressure. Considering the need for a safety margin and the principles of conservative dive planning, the total requirement would be the planned consumption plus a reserve. A common practice is to ensure a reserve that allows for a safe ascent and potential contingencies. The most appropriate answer reflects the planned consumption plus a substantial reserve, ensuring that the diver does not approach the minimum reserve level during the planned dive. The calculation of 5512.5 L SAE represents the air consumed. A prudent diver would plan to have significantly more than this, typically aiming to have a substantial reserve remaining. The options provided represent different interpretations of total gas needs, including reserves. The correct option reflects a total gas supply that comfortably covers the planned consumption and provides a robust safety margin, often interpreted as having at least 50 bar of residual pressure, which translates to a significant volume at surface pressure. The calculation of 5512.5 L SAE is the *consumed* volume. The total supply must be greater than this. The most appropriate answer will be the one that accounts for planned consumption and a substantial, safe reserve, aligning with the principles of autonomous diving safety.

The scenario describes a Level 2 Autonomous Diver who has exceeded their planned bottom time and is ascending. The critical factor here is the potential for decompression sickness (DCS). ISO 24801-2:2014, specifically in relation to autonomous diving, emphasizes diver responsibility for dive planning and execution, including managing ascent rates and potential decompression obligations. While the diver is ascending, the primary concern is to avoid a rapid ascent which can lead to bubble formation and DCS. The standard mandates adherence to dive tables or dive computers for decompression. In this situation, the diver’s immediate action should be to control their ascent rate to prevent DCS. The concept of “safety stop” is a crucial element of managing ascent profiles, particularly after exceeding planned bottom times or operating at deeper depths, to allow for off-gassing of inert gases. Therefore, performing a safety stop at a shallower depth for a specified duration, as per dive computer or table recommendations, is the most appropriate action to mitigate risk. This aligns with the principle of responsible autonomous diving where the diver manages their own safety and adheres to established decompression protocols. The other options represent either inadequate responses or actions that could exacerbate the risk. A rapid ascent is contrary to decompression principles. Continuing to the planned depth would increase nitrogen loading. Acknowledging the error without taking corrective action is insufficient. The core of autonomous diving is self-management and adherence to safety procedures, especially when deviations from the plan occur.

The core principle being tested here is the diver’s responsibility for managing their ascent rate to avoid decompression sickness (DCS). ISO 24801-2:2014 specifies that autonomous divers should be trained to ascend at a controlled rate. A common guideline, often derived from dive tables and computer algorithms, is a maximum ascent rate of 10 meters per minute (or 30 feet per minute). This rate is designed to allow dissolved inert gases in the body’s tissues to off-gas safely through respiration, preventing bubble formation. Exceeding this rate significantly increases the risk of DCS, as gases come out of solution too quickly. Therefore, a diver who ascends from a depth of 30 meters to the surface in 2 minutes has an average ascent rate of \( \frac{30 \text{ meters}}{2 \text{ minutes}} = 15 \text{ meters/minute} \). This rate is double the recommended maximum, indicating a critical deviation from safe diving practices as outlined in standards like ISO 24801-2. The explanation emphasizes the physiological basis for controlled ascents and the potential consequences of rapid ascents, aligning with the training objectives for autonomous divers to manage their own safety. This understanding is crucial for preventing dive-related injuries and ensuring responsible diving.