diff --git a/modules/deeplearning/icing_cnn.py b/modules/deeplearning/icing_cnn.py
index 0bf753001fe11ebab107c7d83377d8bc635c59be..2ee9f47d8fa1a74e578ecbb73c25576644a612c7 100644
--- a/modules/deeplearning/icing_cnn.py
+++ b/modules/deeplearning/icing_cnn.py
@@ -372,7 +372,7 @@ class IcingIntensityNN:
 
         # TODO: altitude data will be specified by user at run-time
         nda = np.zeros([nd_idxs.size])
-        nda = self.flight_level
+        nda[:] = self.flight_level
         nda = tf.one_hot(nda, 5).numpy()
 
         return data, nda