diff --git a/aviary/subsystems/test/test_premission.py b/aviary/subsystems/test/test_premission.py
index cd5b678f5..84e5c42a5 100644
--- a/aviary/subsystems/test/test_premission.py
+++ b/aviary/subsystems/test/test_premission.py
@@ -105,6 +105,8 @@ def setUp(self):
             self.prob.model.set_input_defaults(key, val=val, units=units)
 
         self.prob.model.set_input_defaults(Aircraft.Wing.SPAN, val=1.0, units='ft')
+        self.prob.model.set_input_defaults(Aircraft.Wing.SLAT_SPAN_RATIO, val=0.9)
+        self.prob.model.set_input_defaults(Aircraft.Wing.SLAT_CHORD_RATIO, val=.15)
 
         setup_model_options(self.prob, input_options)