Which checklist should always be accomplished if smoke is filling the pressurized portion of the aircraft?

When smoke fills the pressurized portion of the aircraft, the "Smoke, Fire, or Fumes" checklist must be accomplished as it provides comprehensive guidance on handling situations involving potential fire or smoke hazards within the aircraft. This checklist includes critical procedures for identifying sources of smoke, managing the cabin environment, and ensuring crew and passenger safety.

It emphasizes immediate actions such as identifying the source of the smoke, and if necessary, instructing the cabin crew to assist in smoke removal or to communicate with passengers. This checklist ensures that all necessary steps are taken promptly to address the emergency, assess the situation, and coordinate responses effectively.

While the other checklists may also address specific scenarios related to smoke or electrical issues, they do not encompass the full scope required when dealing with smoke or fumes because they focus on particular aspects rather than providing a complete procedural framework for managing smoke incidents. Hence, the "Smoke, Fire, or Fumes" checklist is the most appropriate and essential to utilize in this situation to ensure safety and proper management of the emergency.