diff --git a/libraries/AP_Common/AP_Test.h b/libraries/AP_Common/AP_Test.h
index 5e705d20ac..732a2416f2 100644
--- a/libraries/AP_Common/AP_Test.h
+++ b/libraries/AP_Common/AP_Test.h
@@ -61,8 +61,8 @@ public:
 private:
     const char  *_name;         ///< name of the current test
     bool        _fail;          ///< set if any ::require calls indicate the test failed
-    static int  _passed;        ///< global pass count
-    static int  _failed;        ///< global fail count
+    static int16_t	_passed;        ///< global pass count
+    static int16_t	_failed;        ///< global fail count
 };
 
 /// Constructor
@@ -104,8 +104,8 @@ Test::report()
     Serial.printf("\n%d passed  %d failed\n", _passed, _failed);
 }
 
-int Test::_passed = 0;
-int Test::_failed = 0;
+int16_t Test::_passed = 0;
+int16_t Test::_failed = 0;
 
 /// Start a new test.
 ///
diff --git a/libraries/AP_Common/AP_Vector.h b/libraries/AP_Common/AP_Vector.h
index bcd081a4d3..0d60ae42a8 100644
--- a/libraries/AP_Common/AP_Vector.h
+++ b/libraries/AP_Common/AP_Vector.h
@@ -309,7 +309,7 @@ public:
         return (*this)*(1/norm());
     }
     // sum
-    const sumType sum(const size_t & start=0,const int & end=-1) const {
+    const sumType sum(const size_t & start=0,const int16_t & end=-1) const {
         size_t end2;
         if (end==-1) end2=getSize()-1;
         else end2=end;
@@ -317,7 +317,7 @@ public:
         for (size_t i=start; i<=end2; i++) _sum += (*this)(i);
         return _sum;
     }
-    void sumFletcher(uint8_t & CK_A, uint8_t & CK_B, const size_t & start=0,const int & end=-1) const {
+    void sumFletcher(uint8_t & CK_A, uint8_t & CK_B, const size_t & start=0,const int16_t & end=-1) const {
         size_t end2;
         if (end==-1) end2=getSize()-1;
         else end2=end;