diff --git a/km3buu/output.py b/km3buu/output.py
index e089d7736ae4ea9f76f0d67848b679acdf83831b..b69462047ee694fb44b2ebf00f52c5f946232507 100644
--- a/km3buu/output.py
+++ b/km3buu/output.py
@@ -259,7 +259,7 @@ class GiBUUOutput:
     @property
     def mean_xsec(self):
         if self.flux_data is None:
-            return self._event_xsec(self.arrays)
+            return lambda energy: self.energy_max
         root_tupledata = self.arrays
         energies = np.array(root_tupledata.lepIn_E)
         weights = self._event_xsec(root_tupledata)