What does the term "lockout" of a Synchro-Self-Shifting (SSS) clutch system mean? See illustration GT-0018

Correct Answer: Option C — SSS clutch will not engage.

Lockout of an SSS clutch prevents the automatic engagement mechanism from functioning, effectively disconnecting the gas turbine from the reduction gear. This feature is essential during maintenance or when the engine must be isolated from the propulsion shafting to prevent unintended rotation or damage during specific operational modes.