diff --git a/libraries/AP_RPM/RPM_HarmonicNotch.cpp b/libraries/AP_RPM/RPM_HarmonicNotch.cpp
index 677ef01bae..eae7178f35 100644
--- a/libraries/AP_RPM/RPM_HarmonicNotch.cpp
+++ b/libraries/AP_RPM/RPM_HarmonicNotch.cpp
@@ -32,10 +32,10 @@ AP_RPM_HarmonicNotch::AP_RPM_HarmonicNotch(AP_RPM &_ap_rpm, uint8_t _instance, A
 void AP_RPM_HarmonicNotch::update(void)
 {
     AP_InertialSensor& ins = AP::ins();
-    for (uint8_t i=0; i<HAL_INS_NUM_HARMONIC_NOTCH_FILTERS; i++) {
-        if (ins.gyro_harmonic_notch_enabled(i) &&
-            ins.get_gyro_harmonic_notch_tracking_mode(i) != HarmonicNotchDynamicMode::Fixed) {
-            state.rate_rpm = ins.get_gyro_dynamic_notch_center_freq_hz(i) * 60.0f;
+    for (auto &notch : ins.harmonic_notches) {
+        if (notch.params.enabled() &&
+            notch.params.tracking_mode() != HarmonicNotchDynamicMode::Fixed) {
+            state.rate_rpm = notch.params.center_freq_hz() * 60;
             state.rate_rpm *= ap_rpm._params[state.instance].scaling;
             state.signal_quality = 0.5f;
             state.last_reading_ms = AP_HAL::millis();