diff --git a/corsika/detail/modules/ObservationPlane.inl b/corsika/detail/modules/ObservationPlane.inl
index cf2b9a342e41ff577e12b2fe5c71aee87a7a2b2f..45861596157e9c340ed1f34e03e1efa1f053d5fa 100644
--- a/corsika/detail/modules/ObservationPlane.inl
+++ b/corsika/detail/modules/ObservationPlane.inl
@@ -46,7 +46,8 @@ namespace corsika {
         return ProcessReturn::Ok;
     }
 
-    HEPEnergyType const energy = step.getEkinPost();
+    HEPEnergyType const energy =
+        step.getEkinPost() + get_mass(step.getParticlePre().getPID());
     Point const pointOfIntersection = step.getPositionPost();
     Vector const displacement = pointOfIntersection - plane_.getCenter();