Gas turbine engine combustion chamber

A gas turbine engine combustion chamber having an interior defined by at least one peripheral wall,

• means to define at least one first fuel and air mixing duct, said first fuel and air mixing duct having an upstream and a downstream end, each first fuel and air mixing duct being in fluid flow communication at its downstream end with said interior of the combustion chamber, each first fuel and air mixing duct having air intake means at its upstream end to supply air into the first fuel and air mixing duct,
• means to define at least one second fuel and air mixing duct, said second fuel and air mixing duct having an upstream and a downstream end, each second fuel and air mixing duct being in fluid flow communication at its downstream end with said interior of the combustion chamber, each second fuel and air mixing duct having air intake means at its upstream end to supply air into the second fuel and air mixing duct,
• fuel injector means to supply fuel to the first and second fuel and air mixing ducts, the fuel injector means comprising a fuel manifold having at least one aperture arranged to direct fuel towards the second air intake means across the first air intake means, means to vary the pressure of the fuel supplied to the fuel injector means such that in operation at pressures greater than a predetermined pressure the fuel is supplied into the at least one second fuel and air mixing duct and at pressures lower than the predetermined pressure the fuel is supplied into the at least one first fuel and air mixing duct.