diff --git a/ArduPlane/sensors.pde b/ArduPlane/sensors.pde
index 6cb289316b..6ac213518c 100644
--- a/ArduPlane/sensors.pde
+++ b/ArduPlane/sensors.pde
@@ -26,7 +26,7 @@ static int32_t read_barometer(void)
 static void init_sonar(void)
 {
 #if CONFIG_HAL_BOARD == HAL_BOARD_APM1
-    sonar.Init(&adc);
+    sonar.Init(&apm1_adc);
 #else
     sonar.Init(NULL);
 #endif