diff --git a/airdata/WindEstimator.cpp b/airdata/WindEstimator.cpp
index 07792b915b..85aca2539d 100644
--- a/airdata/WindEstimator.cpp
+++ b/airdata/WindEstimator.cpp
@@ -326,7 +326,13 @@ WindEstimator::run_sanity_checks()
 	}
 
 	// constrain airspeed scale factor, negative values physically do not make sense
-	_state(tas) = math::max(0.0f, _state(tas));
+	if (_scale_estimation_on) {
+		_state(tas) = math::max(0.0f, _state(tas));
+	} else {
+		_state(tas) = 1.0f;
+	}
+
+
 
 	// attain symmetry
 	for (unsigned row = 0; row < 3; row++) {
diff --git a/airdata/WindEstimator.hpp b/airdata/WindEstimator.hpp
index dee8dc4924..3d458210ca 100644
--- a/airdata/WindEstimator.hpp
+++ b/airdata/WindEstimator.hpp
@@ -88,6 +88,7 @@ public:
 	void set_beta_noise(float beta_var) { _beta_var = beta_var * beta_var; }
 	void set_tas_gate(uint8_t gate_size) {_tas_gate = gate_size; }
 	void set_beta_gate(uint8_t gate_size) {_beta_gate = gate_size; }
+	void set_scale_estimation_on(bool scale_estimation_on) {_scale_estimation_on = scale_estimation_on; }
 
 private:
 	enum {
@@ -120,6 +121,7 @@ private:
 	uint64_t _time_rejected_beta = 0;		///< timestamp of when sideslip measurements have consistently started to be rejected
 	uint64_t _time_rejected_tas =
 		0;		///<timestamp of when true airspeed measurements have consistently started to be rejected
+	bool _scale_estimation_on = false; ///< online scale estimation (IAS-->CAS/EAS) is on
 
 	// initialise state and state covariance matrix
 	bool initialise(const matrix::Vector3f &velI, const matrix::Vector2f &velIvar, const float tas_meas);