We claim:
1. An aeronautical gas turbine engine comprising:
a compressor section including one or more compressors;
a turbine section located downstream of the compressor section and including one or more turbines, the compressor section and the turbine section together defining a core air flowpath (37);
a sump positioned inward of the core air flowpath (37) for containing and collecting lubrication oil; and
a heat exchanger (130) positioned in direct thermal communication with the sump for removing heat from the lubrication oil contained therein.
2. The gas turbine engine as claimed in claim 1, wherein the sump is a forward sump (100) of the gas turbine engine.
3. The gas turbine engine as claimed in claim 1, further comprising:
a fan (38), and wherein the sump is a fan bearings sump (158) of the gas turbine engine.
4. The gas turbine engine as claimed in claim 1, wherein the heat exchanger
(130) is an air-to-liquid heat exchanger, and wherein the heat exchanger (130) is
configured to receive a cooling airflow from the compressor section and to transfer
heat from the lubrication oil in the sump to such cooling airflow.

6. The gas turbine engine as claimed in claim 1, wherein the heat exchanger (130) is a liquid-to-liquid heat exchanger.
7. The gas turbine engine as claimed in claim 6, wherein the heat exchanger (130) is configured with a closed loop thermal transport system (140), and wherein the heat exchanger (130) is configured to transfer heat from the lubrication oil to a thermal transport fluid within the closed loop thermal transport system (140).
8. The gas turbine engine as claimed in claim 1, wherein the heat exchanger (130) is integrated into a wall of the sump, or is positioned at least partially within the sump.
9. The gas turbine engine as claimed in claim 1, wherein the sump defines a collection chamber (124), and wherein the heat exchanger (130) is positioned at least partially within the collection chamber (124).
10. The gas turbine engine as claimed in claim 1, wherein the heat exchanger (130) comprises a plurality of channels extending at least partially through the sump.