diff --git a/cmake/toolchain/heptools-105a_nxcals_pro.cmake b/cmake/toolchain/heptools-105a_nxcals_pro.cmake
index 83f76c6d914fdc460b05a7b4970baafbbef3b4da..30ba6b8560b0bfbd4ecf5d3146609bc343a4e5ee 100644
--- a/cmake/toolchain/heptools-105a_nxcals_pro.cmake
+++ b/cmake/toolchain/heptools-105a_nxcals_pro.cmake
@@ -12,3 +12,5 @@ set(PYTIMBER_VERSION_LIMIT ~=4.0)
 
 set(EOS_PATH_NXCALS_DEV /eos/project/n/nxcals/swan/nxcals_pro)
 include(nxcals)
+
+LCG_external_package(spark           3.5.1 )