As part of the plan to protect these bases a combined US-Australian force would establish a screen to interdict movement along the northern approaches to Long Binh-Bien Hoa. 1 ATF was subsequently allocated the north-eastern sector, into a new area of operations named AO Columbus.
The concept of operations for Operation Coburg called for two infantry companies from 7 RAR to move by road with the rear echelon units in order to secure FSB Andersen, that had been established 1km north of Trang Bom for easy access to Route 1.