In what situations can en route controllers omit the term “heavy” when communicating?

The term "heavy" is used in aviation communications to inform other pilots and controllers that an aircraft is a heavy jet, which affects its wake turbulence. In the context of the provided options, omitting the term “heavy” can be appropriate when discussing heavy jet operations at terminals.

In terminal operations, controllers may have specific procedures and understandings regarding aircraft performance, and the context often implies that the aircraft in question are heavy jets. Therefore, there can be instances where controllers may forgo using "heavy" if the aircraft type, operation, and environment already clearly indicate the nature of the aircraft.

In contrast, routine traffic communications typically require the use of “heavy” to ensure safety and awareness among all aircraft in the vicinity. Emergency procedures often necessitate clear and precise communication, making the term essential in certain contexts. Traffic advisories similarly rely on accurate descriptions to prevent potential conflicts, so omitting “heavy” could lead to misunderstandings. Therefore, it is specifically in terminal discussions about heavy jet operations where the use of the term may not be crucial.