Which of the following is NOT one of the essential pre-dive checks for surface-supplied diving equipment?

• A. Integrity of gas supply (pressure and purity).
• B. Continuity and condition of the umbilical.
• C. Function of the helmet/regulator and communication system.
• D. Routine calibration of the dive computer.

Answer: (D)

The important thing this item tests is what safety-critical items must be checked before a surface-supplied dive to ensure the diver gets breathable gas and reliable communication from the surface. In surface-supplied operations, you verify that the gas supply is present at the correct pressure and is of suitable purity, that the umbilical connection back to the surface is continuous and undamaged, and that the helmet or regulator and the communication system are functioning so the diver can breathe safely and stay in contact with the surface team. These checks address immediate hazards to the diver during the dive.

Routine calibration of a dive computer is not part of the essential pre-dive checks for surface-supplied equipment because the dive computer is a personal device whose calibration is not a safety-critical, surface-delivery failure mode. In this context, the dive computer is not responsible for delivering gas or maintaining the dive’s safety envelope; its use, if any, is ancillary and typically addressed separately through general equipment maintenance and the diver’s own procedures.