What should you look for during a preflight inspection of the AED on a CRJ 200?

During a preflight inspection of the Automated External Defibrillator (AED) on a CRJ 200, it is essential to ensure that the device is ready for use in the event of a cardiac emergency. The correct answer focuses on three critical aspects: the indicator light, the auditory signals of the unit, and the condition of the case.

An indicator light that is green signifies that the AED is operational and has no issues needing attention. A unit that is not beeping indicates that it is not in use and is functioning correctly without any alarms, which would suggest that the device is in standby mode. Additionally, a sealed case is vital as it ensures that the unit has not been tampered with or exposed to elements that might compromise its functionality.

These factors combined indicate that the AED is in the appropriate condition for emergency readiness, allowing crew members to act swiftly and effectively in a medical emergency. The other scenarios presented in the options would indicate potential malfunctions or readiness issues with the AED, such as alarms, unsealed cases, or improper indicator lights, which could hinder the efficacy of the device during a critical situation.