Abstract

A controller (600) for a gas turbine (100) is described. The gas turbine (100) comprises the compressor (101) arranged to operate at a rotational speed n, the combustor (102) and the fuel supply means (127) comprising the first fuel supply means and the second fuel supply means, wherein the compressor (101) is arranged to provide air to the combustor (102) at a steady state air mass flow rate mss and wherein the fuel supply means (127) is arranged to supply fuel at a fuel mass flow rate mtotal to the combustor (102). The controller (600) is arranged to, responsive to a load change L to the load L, control the compressor (101) to provide air to the combustor (102) at a new air mass flow rate m TR , wherein the new air mass flow ratem TR is within a range between a first threshold m LBO and a second threshold m SUR .