diff --git a/src/FDM/SP/ACMS.cxx b/src/FDM/SP/ACMS.cxx
index cab51af07..c5b7eefdd 100644
--- a/src/FDM/SP/ACMS.cxx
+++ b/src/FDM/SP/ACMS.cxx
@@ -78,7 +78,7 @@ void FGACMS::update( double dt ) {
     sgSetVec3(accel_ned, acc_lon, acc_lat, acc_down);
     double accel = sgLengthVec3 (accel_ned) * SG_FEET_TO_METER;
 
-    double velocity = (_speed->getDoubleValue() * SG_KT_TO_MPS) * accel * dt;
+    double velocity = (_speed->getDoubleValue() * SG_KT_TO_MPS) + accel * dt;
     double dist = cos (pitch) * velocity * dt;
     double kts = velocity * SG_MPS_TO_KT;
     _set_V_equiv_kts( kts );