Which switch is used to check the operation of all the smoke detectors?

The TEST/ARM/OFF switch on the overhead panel is used to check the operation of all the smoke detectors in the C-17. This switch allows for a thorough system check to ensure that each of the detectors is functioning properly. When the smoke detection system is tested using this switch, it performs a comprehensive assessment of all detectors, providing the crew with confirmation of their operational status.

Understanding the other choices is also beneficial. The indicator TEST switch on the aft left loadmaster panel and the TEST/ARM/OFF switch on the forward loadmaster panel are specific to different systems or may not encompass all smoke detectors, thus limiting their utility in this scenario. The detector test switch on the control pedestal may test individual detectors, but it does not offer the same comprehensive functionality provided by the overhead panel switch. Therefore, the overhead panel's TEST/ARM/OFF switch is the definitive choice for checking all smoke detector operations.