diff --git a/libraries/APM_RC/APM_RC.cpp b/libraries/APM_RC/APM_RC.cpp
index cda973f31f..9faaf6e720 100644
--- a/libraries/APM_RC/APM_RC.cpp
+++ b/libraries/APM_RC/APM_RC.cpp
@@ -30,7 +30,7 @@
 // Variable definition for Input Capture interrupt
 volatile unsigned int ICR4_old;
 volatile unsigned char PPM_Counter=0;
-volatile unsigned int PWM_RAW[8] = {2400,2400,2400,2400,2400,2400,2400,2400};
+volatile uint16_t PWM_RAW[8] = {2400,2400,2400,2400,2400,2400,2400,2400};
 volatile unsigned char radio_status=0;
 
 /****************************************************
@@ -123,7 +123,7 @@ void APM_RC_Class::Init(void)
   TIMSK4 |= (1<<ICIE4); // Enable Input Capture interrupt. Timer interrupt mask
 }
 
-void APM_RC_Class::OutputCh(unsigned char ch, int pwm)
+void APM_RC_Class::OutputCh(unsigned char ch, uint16_t pwm)
 {
   pwm=constrain(pwm,MIN_PULSEWIDTH,MAX_PULSEWIDTH);
   pwm<<=1;   // pwm*2;
@@ -144,10 +144,10 @@ void APM_RC_Class::OutputCh(unsigned char ch, int pwm)
   } 
 }
 
-int APM_RC_Class::InputCh(unsigned char ch)
+uint16_t APM_RC_Class::InputCh(unsigned char ch)
 {
-  int result;
-  int result2;
+  uint16_t result;
+  uint16_t result2;
   
   // Because servo pulse variables are 16 bits and the interrupts are running values could be corrupted.
   // We dont want to stop interrupts to read radio channels so we have to do two readings to be sure that the value is correct...
diff --git a/libraries/APM_RC/APM_RC.h b/libraries/APM_RC/APM_RC.h
index b3fa06da44..9d81b38fcf 100644
--- a/libraries/APM_RC/APM_RC.h
+++ b/libraries/APM_RC/APM_RC.h
@@ -5,14 +5,16 @@
 #define MIN_PULSEWIDTH 900
 #define MAX_PULSEWIDTH 2100
 
+#include <inttypes.h>
+
 class APM_RC_Class
 {
   private:
   public:
 	APM_RC_Class();
 	void Init();
-	void OutputCh(unsigned char ch, int pwm);
-	int InputCh(unsigned char ch);
+	void OutputCh(unsigned char ch, uint16_t pwm);
+	uint16_t InputCh(unsigned char ch);
 	unsigned char GetState();
 	void Force_Out0_Out1(void);
 	void Force_Out2_Out3(void);
@@ -21,4 +23,4 @@ class APM_RC_Class
 
 extern APM_RC_Class APM_RC;
 
-#endif
\ No newline at end of file
+#endif