diff --git a/jsonpath/patch.py b/jsonpath/patch.py
index ce5c054..913987c 100644
--- a/jsonpath/patch.py
+++ b/jsonpath/patch.py
@@ -124,7 +124,7 @@ class OpAddAp(OpAdd):
     """A non-standard add operation that appends to arrays/lists .
 
     This is like _OpAdd_, but assumes an index of "-" if the path can not
-    be resolved.
+    be resolved rather than raising a JSONPatchError.
 
     **New in version 1.2.0**
     """
@@ -419,7 +419,7 @@ def _build(self, patch: Iterable[Mapping[str, object]]) -> None:
                     value=self._op_value(operation, "value", "addne", i),
                 )
             elif op == "addap":
-                self.addne(
+                self.addap(
                     path=self._op_pointer(operation, "path", "addap", i),
                     value=self._op_value(operation, "value", "addap", i),
                 )
diff --git a/tests/test_json_patch.py b/tests/test_json_patch.py
index eec2db7..64fafaf 100644
--- a/tests/test_json_patch.py
+++ b/tests/test_json_patch.py
@@ -262,3 +262,9 @@ def test_asdict() -> None:
 
     patch = JSONPatch(patch_doc)
     assert patch.asdicts() == patch_doc
+
+
+def test_non_standard_addap_op() -> None:
+    # Index 7 is out of range and would raises a JSONPatchError with the `add` op.
+    patch = JSONPatch().addap(path="/foo/7", value=99)
+    assert patch.apply({"foo": [1, 2, 3]}) == {"foo": [1, 2, 3, 99]}