diff --git a/flight/modules/StateEstimation/filteraltitude.c b/flight/modules/StateEstimation/filteraltitude.c
index 0bea2411f..3b4a047f8 100644
--- a/flight/modules/StateEstimation/filteraltitude.c
+++ b/flight/modules/StateEstimation/filteraltitude.c
@@ -38,6 +38,12 @@
 
 // Private constants
 
+// Acceldrift ki value used at startup to let it quickly converge
+// to its target value
+#define INITIALIZATION_ACCELDRIFT_KI 0.2f
+// lenght of accel bias initialization phase
+#define INITIALIZATION_DURATION 5000
+
 #define STACK_REQUIRED 128
 
 #define DT_ALPHA       1e-2f
@@ -146,9 +152,9 @@ static int32_t filter(stateFilter *self, stateEstimation *state)
 
             // low pass filter accelerometers
             this->accelState = (1.0f - this->settings.AccelLowPassKp) * this->accelState + this->settings.AccelLowPassKp * current;
-            if (((xTaskGetTickCount() - this->initTimer) / portTICK_RATE_MS) < 5000) {
+            if (((xTaskGetTickCount() - this->initTimer) / portTICK_RATE_MS) < INITIALIZATION_DURATION) {
                 // allow the offset to reach quickly the target value in case of small AccelDriftKi
-                this->accelBiasState = (1.0f - 0.2f) * this->accelBiasState + 0.2f * this->accelState;
+                this->accelBiasState = (1.0f - INITIALIZATION_ACCELDRIFT_KI) * this->accelBiasState + INITIALIZATION_ACCELDRIFT_KI * this->accelState;
             } else {
                 // correct accel offset (low pass zeroing)
                 this->accelBiasState = (1.0f - this->settings.AccelDriftKi) * this->accelBiasState + this->settings.AccelDriftKi * this->accelState;