Between the old IFATC Manual and the new one on Infinite Flight’s website, the requirements for controllers to allow pattern work have changed. Oftentimes controllers will see traffic greatly increase at their airport, turn off pattern work to handle the rush, and then forget to turn it back on. This should be no more.
3.3.1 of the new ATC Manual states that “if CURRENT traffic levels increase to a level that prevents Controllers from providing an adequate service, pattern work should be turned off TEMPORARILY – as soon as traffic levels are manageable, Controllers must resume pattern work.” This new guideline for controllers should help to remind them that once the rush of traffic is gone, they can allow patterns again.
Besides that, not much has changed for pattern work requirements. The minimum three statute miles of visibility and ability for aircraft to perform a standard pattern (upwind, crosswind, downwind, base, and final) without interfering with terrain must still be met. If either of those conditions cannot be met, patterns must not be allowed.