A gas turbine engine comprises: a bearing compartment (62a,62b), wherein the bearing compartment (62a,62b) comprises: a bottom (68a,68b) disposed opposite a top (70a,70b); an outlet (72a,72b) formed in the bottom (68a,68b) of the bearing compartment (62a,62b); and a seal (76a,76b) positioned between the bottom (68a,68b) of the bearing compartment (62a,62b) and the top (70a,70b) of the bearing compartment (62a,62b); and a scavenge line (66a,66b) connected to the outlet (72a,72b), wherein the scavenge line (66a,66b) forms a lubricant fluid trap (88a,88b) that extends in a first direction from the outlet (72a,72b) and the bottom (68a,68b) of the bearing compartment (62a,62b) and then extends in a second direction to a position disposed vertically between the bottom (68a,68b) of the bearing compartment (62a,62b) and the seal (76a,76b), wherein the bearing compartment (62a,62b) is disposed within a core casing of the gas turbine engine; characterised in that: the bearing compartment (62a,62b) comprises an inlet (74a,74b) formed in the bottom (68a,68b) of the bearing compartment (62a,62b) and the gas turbine engine further comprises a lubricant fluid supply line (82a,82b) connected to the inlet (74a,74b), wherein the fluid supply line (82a,82b) first extends vertically downward from the inlet (74a,74b) and the bottom (68a,68b) of the bearing compartment (62a,62b) and exits the core casing, and then extends upward to a position disposed vertically above the top (70a,70b) of the bearing compartment (62a,62b). a bearing compartment (62a,62b), wherein the bearing compartment (62a,62b) comprises: a bottom (68a,68b) disposed opposite a top (70a,70b); an outlet (72a,72b) formed in the bottom (68a,68b) of the bearing compartment (62a,62b); and a seal (76a,76b) positioned between the bottom (68a,68b) of the bearing compartment (62a,62b) and the top (70a,70b) of the bearing compartment (62a,62b); and a bottom (68a,68b) disposed opposite a top (70a,70b); an outlet (72a,72b) formed in the bottom (68a,68b) of the bearing compartment (62a,62b); and a seal (76a,76b) positioned between the bottom (68a,68b) of the bearing compartment (62a,62b) and the top (70a,70b) of the bearing compartment (62a,62b); and a scavenge line (66a,66b) connected to the outlet (72a,72b), wherein the scavenge line (66a,66b) forms a lubricant fluid trap (88a,88b) that extends in a first direction from the outlet (72a,72b) and the bottom (68a,68b) of the bearing compartment (62a,62b) and then extends in a second direction to a position disposed vertically between the bottom (68a,68b) of the bearing compartment (62a,62b) and the seal (76a,76b), wherein the bearing compartment (62a,62b) is disposed within a core casing of the gas turbine engine; characterised in that: the bearing compartment (62a,62b) comprises an inlet (74a,74b) formed in the bottom (68a,68b) of the bearing compartment (62a,62b) and the gas turbine engine further comprises a lubricant fluid supply line (82a,82b) connected to the inlet (74a,74b), wherein the fluid supply line (82a,82b) first extends vertically downward from the inlet (74a,74b) and the bottom (68a,68b) of the bearing compartment (62a,62b) and exits the core casing, and then extends upward to a position disposed vertically above the top (70a,70b) of the bearing compartment (62a,62b).