From 31ca7206955a20fa512cb5c4a1e37b32cf1c60e7 Mon Sep 17 00:00:00 2001
From: Sean McLeod <sean@seanmcleod.com>
Date: Thu, 27 Apr 2023 19:35:27 +0200
Subject: [PATCH] Correct VEAS to use standard day SL density

---
 src/FGFDMExec.cpp          | 1 -
 src/models/FGAtmosphere.h  | 3 +++
 src/models/FGAuxiliary.cpp | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/FGFDMExec.cpp b/src/FGFDMExec.cpp
index d5b39c8de1..1b1616d238 100644
--- a/src/FGFDMExec.cpp
+++ b/src/FGFDMExec.cpp
@@ -464,7 +464,6 @@ void FGFDMExec::LoadInputs(unsigned int idx)
   case eAuxiliary:
     Auxiliary->in.Pressure     = Atmosphere->GetPressure();
     Auxiliary->in.Density      = Atmosphere->GetDensity();
-    Auxiliary->in.DensitySL    = Atmosphere->GetDensitySL();
     Auxiliary->in.PressureSL   = Atmosphere->GetPressureSL();
     Auxiliary->in.Temperature  = Atmosphere->GetTemperature();
     Auxiliary->in.SoundSpeed   = Atmosphere->GetSoundSpeed();
diff --git a/src/models/FGAtmosphere.h b/src/models/FGAtmosphere.h
index 95d54e486b..06f297e4d9 100644
--- a/src/models/FGAtmosphere.h
+++ b/src/models/FGAtmosphere.h
@@ -293,6 +293,9 @@ class JSBSIM_API FGAtmosphere : public FGModel {
 
   virtual void bind(void);
   void Debug(int from) override;
+
+public:
+  static constexpr double StdDaySLdensity = StdDaySLpressure / (Reng0 * StdDaySLtemperature);
 };
 
 } // namespace JSBSim
diff --git a/src/models/FGAuxiliary.cpp b/src/models/FGAuxiliary.cpp
index c28346f963..bc854aaa92 100644
--- a/src/models/FGAuxiliary.cpp
+++ b/src/models/FGAuxiliary.cpp
@@ -198,7 +198,7 @@ bool FGAuxiliary::Run(bool Holding)
 
   if (abs(Mach) > 0.0) {
     vcas = VcalibratedFromMach(Mach, in.Pressure);
-    veas = sqrt(2 * qbar / in.DensitySL);
+    veas = sqrt(2 * qbar / FGAtmosphere::StdDaySLdensity);
   }
   else
     vcas = veas = 0.0;