A gas turbine engine comprising: an outer case; a core inside the outer case, the core including: a combustor, at least one spool mounted for rotation about a central axis, the at least one spool including a compressor and a turbine, an annular gas path extending between the compressor and the turbine about the central axis; and a turbine exhaust duct extending from the annular gas path downstream of the turbine in a direction away from the central axis, the turbine exhaust duct having a downstream end portion (30b; 30c) projecting outwardly from the outer case, the downstream end portion (30b; 30c) instrumented with exhaust gas temperature probes (50; 52), characterised in that: the EGT probes (50; 52) are electrically interconnected by a wiring harness outside the turbine exhaust duct and are distributed around the downstream end portion (30b; 30c) of the turbine exhaust duct outside the outer case of the gas turbine engine; and the downstream end portion (30b; 30c) of the turbine exhaust duct defines an exhaust port opening surrounded by an annular flange, and wherein a shield is detachably mounted to the annular flange, the shield having an annular skirt surrounding the EGT probes (50; 52) around the downstream end portion (30b; 30c) of the turbine exhaust duct, the annular skirt forming an annulus around the downstream end portion (30b; 30c) of the turbine exhaust duct, the wiring harness accommodated in the annulus. an outer case; a core inside the outer case, the core including: a combustor, at least one spool mounted for rotation about a central axis, the at least one spool including a compressor and a turbine, an annular gas path extending between the compressor and the turbine about the central axis; and a turbine exhaust duct extending from the annular gas path downstream of the turbine in a direction away from the central axis, the turbine exhaust duct having a downstream end portion (30b; 30c) projecting outwardly from the outer case, the downstream end portion (30b; 30c) instrumented with exhaust gas temperature probes (50; 52), characterised in that: the EGT probes (50; 52) are electrically interconnected by a wiring harness outside the turbine exhaust duct and are distributed around the downstream end portion (30b; 30c) of the turbine exhaust duct outside the outer case of the gas turbine engine; and the downstream end portion (30b; 30c) of the turbine exhaust duct defines an exhaust port opening surrounded by an annular flange, and wherein a shield is detachably mounted to the annular flange, the shield having an annular skirt surrounding the EGT probes (50; 52) around the downstream end portion (30b; 30c) of the turbine exhaust duct, the annular skirt forming an annulus around the downstream end portion (30b; 30c) of the turbine exhaust duct, the wiring harness accommodated in the annulus. a combustor, at least one spool mounted for rotation about a central axis, the at least one spool including a compressor and a turbine, an annular gas path extending between the compressor and the turbine about the central axis; and a turbine exhaust duct extending from the annular gas path downstream of the turbine in a direction away from the central axis, the turbine exhaust duct having a downstream end portion (30b; 30c) projecting outwardly from the outer case, the downstream end portion (30b; 30c) instrumented with exhaust gas temperature probes (50; 52), characterised in that: the EGT probes (50; 52) are electrically interconnected by a wiring harness outside the turbine exhaust duct and are distributed around the downstream end portion (30b; 30c) of the turbine exhaust duct outside the outer case of the gas turbine engine; and the downstream end portion (30b; 30c) of the turbine exhaust duct defines an exhaust port opening surrounded by an annular flange, and wherein a shield is detachably mounted to the annular flange, the shield having an annular skirt surrounding the EGT probes (50; 52) around the downstream end portion (30b; 30c) of the turbine exhaust duct, the annular skirt forming an annulus around the downstream end portion (30b; 30c) of the turbine exhaust duct, the wiring harness accommodated in the annulus. the EGT probes (50; 52) are electrically interconnected by a wiring harness outside the turbine exhaust duct and are distributed around the downstream end portion (30b; 30c) of the turbine exhaust duct outside the outer case of the gas turbine engine; and the downstream end portion (30b; 30c) of the turbine exhaust duct defines an exhaust port opening surrounded by an annular flange, and wherein a shield is detachably mounted to the annular flange, the shield having an annular skirt surrounding the EGT probes (50; 52) around the downstream end portion (30b; 30c) of the turbine exhaust duct, the annular skirt forming an annulus around the downstream end portion (30b; 30c) of the turbine exhaust duct, the wiring harness accommodated in the annulus.