Which of the following is rarely issued by en route controllers?

The correct answer highlights the role of en route controllers and the typical responsibilities associated with their position. En route controllers primarily manage aircraft that are in the cruise phase of flight while they are between departure and arrival airports, operating at altitudes typically above 24,000 feet.

Standard Instrument Departures, or SIDs, are specific procedures published for the departure phase of a flight that guide aircraft from the airport to the en route structure. These are primarily issued by ground and tower controllers, who manage aircraft during the initial ascent after takeoff. Therefore, it is indeed rare for en route controllers to issue SIDs, as those responsibilities fall outside their typical scope of operations.

On the other hand, Standard Terminal Arrivals (STARs) are utilized during the approach phase to guide aircraft into terminal areas, and en route controllers may work with them as flights move from en route airspace to terminal airspace. Traffic advisories are commonplace as they provide pilots with information on other aircraft in the vicinity to ensure safety and efficient operations. Route clearances are typically provided before departures but not during the en route phase, which might partly contribute to the misunderstanding about their issuance by en route controllers.

Understanding these roles clarifies why SIDs are not something en