A generally annular combustion chamber for a gas turbine engine is disclosed having fuel injector assemblies, each with an oxidizer swirler, extending through an upstream end wall of the combustion chamber and control means connected to the control diaphragms of the oxidizer swirlers in order to move the control diaphragms between maximum and minimum flow positions. The upstream end wall of the combustion chamber defines complementary oxidizer intake orifices which have movable closure plates to selectively open or close the complementary oxidizer intake orifices. A mechanical linkage connects the closure plates to the control diaphragm of an adjacent air swirler such that, when the control diaphragms are in their maximum flow positions, the closure plates close the complementary oxidizer intake orifices, and when the control diaphragms are in their minimum flow positions, the closure plates are moved such that the complementary oxidizer intake orifices are fully open.