diff --git a/libraries/AP_Notify/ToneAlarm_PX4.cpp b/libraries/AP_Notify/ToneAlarm_PX4.cpp
index 09fae9b162..e74f5dab9e 100644
--- a/libraries/AP_Notify/ToneAlarm_PX4.cpp
+++ b/libraries/AP_Notify/ToneAlarm_PX4.cpp
@@ -91,6 +91,8 @@ const ToneAlarm_PX4::Tone ToneAlarm_PX4::_tones[] {
     { "MBT255L8>A+AA-", true},
     #define AP_NOTIFY_PX4_TONE_QUIET_SHUTDOWN 27
     { "MFMST200L32O3ceP32cdP32ceP32c<c>c<cccP8L32>c>c<P32<c<c", false },
+    #define AP_NOTIFY_PX4_TONE_QUIET_NOT_READY_OR_NOT_FINISHED 28
+    { "MFT200L4<B#4A#6G#6", false },
 };
 
 bool ToneAlarm_PX4::init()
@@ -275,6 +277,8 @@ void ToneAlarm_PX4::update()
         flags.pre_arm_check = AP_Notify::flags.pre_arm_check;
         if (flags.pre_arm_check) {
             play_tone(AP_NOTIFY_PX4_TONE_QUIET_READY_OR_FINISHED);
+        } else {
+            play_tone(AP_NOTIFY_PX4_TONE_QUIET_NOT_READY_OR_NOT_FINISHED);
         }
     }