diff --git a/src/MNH/flat_inv.f90 b/src/MNH/flat_inv.f90
index e1408a5b4552853cf312d15bcda98cbe5d22b1a7..ab0bf19654cce00c68e446222e4012b43dabc024 100644
--- a/src/MNH/flat_inv.f90
+++ b/src/MNH/flat_inv.f90
@@ -496,7 +496,7 @@ IF (.NOT. L2D) THEN
   IF (HLBCY(1) == 'CYCL') THEN
     ZBAND1D( 1 : SIZE(ZBAND_YRT,1)*SIZE(ZBAND_YRT,2)*SIZE(ZBAND_YRT(:,:,IKB-1:),3) ) => ZBAND_YRT(:,:,IKB-1:)
     ZWORK1D( 1 : SIZE(ZWORKY) ) => ZWORKY(:,:,:)
-    CALL FFT991( ZBAND1D, ZBAND_YRT, PTRIGSY, KIFAXY, INC2Y, IJMAX,ILOTY, +1, &
+    CALL FFT991( ZBAND1D, ZWORK1D, PTRIGSY, KIFAXY, INC2Y, IJMAX,ILOTY, +1, &
                  SIZE(ZBAND1D), SIZE(ZWORK1D), SIZE(PTRIGSY) )
   ELSE
     CALL FFT55( ZBAND_YRT(1:,1:,IKB-1:), ZWORKY, PTRIGSY, KIFAXY, INC2Y, IJMAX, ILOTY, +1 )