diff --git a/libraries/AP_ESC_Telem/AP_ESC_Telem.h b/libraries/AP_ESC_Telem/AP_ESC_Telem.h
index b9e43113ff..b427031a0a 100644
--- a/libraries/AP_ESC_Telem/AP_ESC_Telem.h
+++ b/libraries/AP_ESC_Telem/AP_ESC_Telem.h
@@ -68,7 +68,7 @@ public:
 
     // return the last time telemetry data was received in ms for the given ESC or 0 if never
     uint32_t get_last_telem_data_ms(uint8_t esc_index) const {
-        if (esc_index > ESC_TELEM_MAX_ESCS) return 0;
+        if (esc_index >= ESC_TELEM_MAX_ESCS) {return 0;}
         return _telem_data[esc_index].last_update_ms;
     }