Free Mixed Gas Diving Supervisor Practice Questions

Question 1

A diver is working at 198 fsw on heliox containing 16% oxygen. Before a proposed gas change, the manifold operator confirms that the replacement supply contains 20% oxygen. The project's maximum permitted working oxygen partial pressure is 1.30 ata. At sea level, using 33 fsw per additional atmosphere, which assessment of the replacement supply is correct?

Accepted Answer

1.40 ata; the replacement supply exceeds the project's working limit.

Answer

1.12 ata; the replacement supply is within the project's working limit.

Answer

1.20 ata; acceptable under the project's working limit.

Answer

1.40 ata; the replacement supply is acceptable because it remains below 1.60 ata.

Question 2

On a spare heliox panel, a pressure-reducing regulator's outlet initially settles at 160 psig when flow stops. With the downstream valve shut, pressure then keeps rising to 205 psig. Inlet pressure and gas temperature remain steady, and a second calibrated gauge confirms the rise. Which fault should be suspected?

Accepted Answer

Leakage past the regulator's valve seat.

Answer

Excessive delivery-hose pressure loss.

Answer

Supply-pressure effect from an emptying storage bank.

Answer

Normal regulator lock-up when downstream gas flow stops.

Question 3

The vessel master asks the on-duty diving supervisor to attend a meeting on the bridge while a heliox diver is working. Another mixed-gas supervisor, already vetted and formally appointed by the employer, is available at the dive station and has no conflicting duty. How can immediate supervisory control be maintained during the meeting?

Accepted Answer

Conduct an on-station handover to the appointed supervisor, covering the current profile, gas status and hazards.

Answer

Continue supervising by portable radio from the bridge while the senior tender operates dive control.

Answer

Recover the diver because responsibility for an active mixed-gas dive cannot be handed over.

Answer

Let the standby diver take temporary charge while retaining responsibility from the bridge.

Question 4

An unplanned surface-gas failure causes a diver to open the diver-worn emergency gas supply. The team restores a verified surface supply, and the diver reports normal breathing with no injury or loss of depth control. One bolt remains to be tightened. What should the supervisor authorize?

Accepted Answer

Termination of the working phase and recovery with the required decompression.

Answer

Completion of the bolt, provided the restored supply remains stable and the standby diver is ready.

Answer

Immediate ascent directly to the surface because reserve-gas use overrides scheduled decompression.

Answer

Replacement of the bailout cylinder by the standby diver so that the working diver can finish.

Question 5

At a flooded cooling-water intake, the pump motor is locked out. Drawings also show a gravity-fed connection to a reservoir with a higher water level. Which finding would resolve the remaining differential-pressure concern before the diving permit is signed?

Accepted Answer

The gravity-fed path is positively isolated and the worksite pressure differential is eliminated.

Answer

The motor's electrical isolation has been independently witnessed and entered in the permit records.

Answer

The standby diver has a recovery route and an umbilical longer than the working diver's.

Answer

The intake pump cannot be restarted from either the local or the remote control station.

Question 6

A staffing review covers one planned surface-supplied heliox dive and its decompression. All proposed personnel have the necessary qualifications for their assigned roles. Before adding personnel for task-specific hazards, which assignment matches ADCI's minimum personnel list?

Accepted Answer

One non-rotating supervisor; one working diver; one standby diver; two tender/divers.

Answer

One non-rotating supervisor; one working diver; one standby diver; one tender/diver.

Answer

One non-rotating supervisor; two working divers; two tender/divers.

Answer

One supervisor who takes a working dive in the rotation; one standby diver; three tender/divers.

Question 7

Two analysed heliox supplies feed a selector valve and then one common delivery line to the diver. The oxygen analyzer samples supply A before the selector. After changeover to supply B, that reading remains unchanged. Where must the in-line analyzer sample to verify the gas actually being delivered through either selection?

Accepted Answer

From the common diver-delivery line downstream of the selector valve.

Answer

At supply B's outlet, upstream of the selector valve.

Answer

At supply A's regulator outlet before the selector valve.

Answer

From the blending skid's outlet before either storage supply is filled.

Question 8

During a 46-year-old male diver's annual medical examination, the physician calculates a Framingham ten-year cardiac risk of 12%. The diver reports no symptoms and has a normal resting 12-lead ECG. Which interpretation is consistent with ADCI's medical screening guidance?

Accepted Answer

The elevated calculated risk calls for further cardiac testing despite the normal resting 12-lead ECG.

Answer

The normal resting ECG makes additional cardiac investigation unnecessary at this examination.

Answer

A risk above 10% establishes permanent medical disqualification from commercial diving work.

Answer

The risk should be recalculated next year before any additional cardiac testing is arranged.

Question 9

A diver is symptom-free 25 minutes after completing scheduled decompression from a surface-supplied heliox dive outside the no-decompression limits. He asks to sleep in a berth beside the dive station. What instruction matches ADCI's immediate post-dive observation recommendation?

Accepted Answer

Remain awake near the chamber for at least one hour after completing decompression.

Answer

Sleep in the nearby berth now, provided another team member wakes you at regular intervals.

Answer

Re-enter the chamber for omitted-decompression management before being released to rest after this dive.

Answer

Leave the dive site now, provided you remain within two hours' travel of an operational chamber.

Question 10

The escape route from a worksite at 198 fsw to an independently supplied bell takes 4.5 minutes, all at that depth. A bailout cylinder holds 50 standard cubic feet at its rated fill pressure of 3,000 psig; its current pressure is 2,700 psig. For this equipment at that depth, gas below 300 psig is unavailable. Use a breathing demand of 1.5 actual cubic feet per minute at the diver's ambient pressure, sea-level conditions, 33 fsw per additional atmosphere, and an isothermal ideal-gas approximation. Before adding any contingency margin, how does the usable endurance compare with the escape time?

Accepted Answer

About 3.8 minutes; insufficient for the specified escape route.

Answer

About 4.8 minutes; enough to complete the specified escape route.

Answer

About 4.3 minutes; insufficient to complete the specified escape route.

Answer

About 26.7 minutes; enough to complete the specified escape route.

Free Mixed Gas Diving Supervisor Practice Questions

Domain 1: HeO2/Mixed-Gas Diving Supervisor responsibilities, qualifications and certification

Question 1

Question 2

Question 3

Domain 2: Surface-Supplied Mixed-Gas Diving (HeO2)

Question 4

Question 5

Question 6

Domain 3: Underwater Operations: Procedures, Checklists and Guidelines

Question 7

Question 8

Domain 4: Life-Support Equipment: Requirements, Maintenance and Testing

Question 9

Question 10

The rest of the Mixed Gas Diving Supervisor blueprint

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