diff --git a/Systems/a320-mass-balance.xml b/Systems/a320-mass-balance.xml
index e5182d24..338c357d 100644
--- a/Systems/a320-mass-balance.xml
+++ b/Systems/a320-mass-balance.xml
@@ -10,7 +10,7 @@
 <mass_balance>
 	<ixx unit="SLUG*FT2">  611903 </ixx>
 	<iyy unit="SLUG*FT2"> 1735389 </iyy>
-	<izz unit="SLUG*FT2"> 2301293 </izz>
+	<izz unit="SLUG*FT2"> 1401293 </izz>
 
 	<ixy unit="SLUG*FT2">       0 </ixy>
 	<ixz unit="SLUG*FT2">       0 </ixz>
diff --git a/revision.txt b/revision.txt
index c2a3403e..05fb9346 100644
--- a/revision.txt
+++ b/revision.txt
@@ -1 +1 @@
-4632
\ No newline at end of file
+4633
\ No newline at end of file