diff --git a/src/modules/land_detector/MulticopterLandDetector.cpp b/src/modules/land_detector/MulticopterLandDetector.cpp
index a87c3a6658..43b3a935b2 100644
--- a/src/modules/land_detector/MulticopterLandDetector.cpp
+++ b/src/modules/land_detector/MulticopterLandDetector.cpp
@@ -135,6 +135,11 @@ bool MulticopterLandDetector::get_freefall_state()
 
 	const uint64_t now = hrt_absolute_time();
 
+	if (_ctrl_state.timestamp == 0) {
+		// _ctrl_state is not valid yet, we have to assume we're not falling.
+		return false;
+	}
+
 	float acc_norm = _ctrl_state.x_acc * _ctrl_state.x_acc
 			 + _ctrl_state.y_acc * _ctrl_state.y_acc
 			 + _ctrl_state.z_acc * _ctrl_state.z_acc;