What must the crew do if a fire extinguisher is discharged in the flight compartment?

In the event that a fire extinguisher is discharged in the flight compartment, it's essential for the crew to don oxygen masks with emergency selected. This action is crucial because discharging a fire extinguisher can produce harmful gases and reduce the quality of air within the cockpit, creating a hazardous environment for the crew. By wearing oxygen masks, the pilots can ensure they have an adequate supply of breathable air, which is vital for maintaining their ability to control the aircraft and make informed decisions in an emergency situation.

While activating emergency landing procedures, notifying air traffic control, or beginning a rapid descent could all be steps taken depending on the severity of the situation, the immediate priority following the discharge of a fire extinguisher is to protect the crew from potential smoke inhalation and maintain cognitive function to handle the incident effectively.