diff --git a/src/modules/commander/Arming/PreFlightCheck/PreFlightCheck.cpp b/src/modules/commander/Arming/PreFlightCheck/PreFlightCheck.cpp
index f9e3c645cf..1e377f2a84 100644
--- a/src/modules/commander/Arming/PreFlightCheck/PreFlightCheck.cpp
+++ b/src/modules/commander/Arming/PreFlightCheck/PreFlightCheck.cpp
@@ -88,38 +88,40 @@ bool PreFlightCheck::preflightCheck(orb_advert_t *mavlink_log_pub, vehicle_statu
 
 	/* ---- MAG ---- */
 	if (checkSensors) {
-		bool prime_found = false;
-
-		int32_t prime_id = -1;
-		param_get(param_find("CAL_MAG_PRIME"), &prime_id);
-
 		int32_t sys_has_mag = 1;
 		param_get(param_find("SYS_HAS_MAG"), &sys_has_mag);
 
-		bool mag_fail_reported = false;
+		if (sys_has_mag == 1) {
 
-		/* check all sensors individually, but fail only for mandatory ones */
-		for (unsigned i = 0; i < max_optional_mag_count; i++) {
-			const bool required = (i < max_mandatory_mag_count) && (sys_has_mag == 1);
-			const bool report_fail = (reportFailures && !failed && !mag_fail_reported);
+			bool prime_found = false;
 
-			int32_t device_id = -1;
+			int32_t prime_id = -1;
+			param_get(param_find("CAL_MAG_PRIME"), &prime_id);
 
-			if (magnometerCheck(mavlink_log_pub, status, i, !required, device_id, report_fail)) {
+			bool mag_fail_reported = false;
 
-				if ((prime_id > 0) && (device_id == prime_id)) {
-					prime_found = true;
-				}
+			/* check all sensors individually, but fail only for mandatory ones */
+			for (unsigned i = 0; i < max_optional_mag_count; i++) {
+				const bool required = (i < max_mandatory_mag_count) && (sys_has_mag == 1);
+				const bool report_fail = (reportFailures && !failed && !mag_fail_reported);
 
-			} else {
-				if (required) {
-					failed = true;
-					mag_fail_reported = true;
+				int32_t device_id = -1;
+
+				if (magnometerCheck(mavlink_log_pub, status, i, !required, device_id, report_fail)) {
+
+					if ((prime_id > 0) && (device_id == prime_id)) {
+						prime_found = true;
+					}
+
+				} else {
+					if (required) {
+						failed = true;
+						mag_fail_reported = true;
+					}
 				}
 			}
-		}
 
-		if (sys_has_mag == 1) {
+
 			/* check if the primary device is present */
 			if (!prime_found) {
 				if (reportFailures && !failed) {