diff --git a/src/Uploader.cxx b/src/Uploader.cxx
index 8d00f8a..e68c053 100644
--- a/src/Uploader.cxx
+++ b/src/Uploader.cxx
@@ -290,14 +290,19 @@ vector<Json::Value> *Uploader::flights()
 
         const Json::Value &key = row["key"], &doc = row["doc"];
 
-        if (!doc.isObject() || !key.isArray() || key.size() != 3 ||
-                !key[2u].isIntegral())
-            throw runtime_error("Invalid response: bad key or doc in row");
+        bool doc_ok = doc.isObject() && doc.size();
+        bool key_ok = key.isArray() && key.size() == 3 && key[2u].isIntegral();
+
+        if (!key_ok)
+            throw runtime_error("Invalid response: bad key in row");
 
         bool is_pcfg = key[2u].asBool();
 
         if (!is_pcfg)
         {
+            if (!doc_ok)
+                throw runtime_error("Invalid response: bad doc in row");
+
             result->push_back(doc);
             /* copies the doc */
 
@@ -307,7 +312,8 @@ vector<Json::Value> *Uploader::flights()
         }
         else
         {
-            current_pcfg_list->append(doc);
+            if (doc_ok)
+                current_pcfg_list->append(doc);
         }
     }
 
diff --git a/tests/test_uploader.py b/tests/test_uploader.py
index ccdf952..f552cb4 100644
--- a/tests/test_uploader.py
+++ b/tests/test_uploader.py
@@ -749,6 +749,8 @@ class TestCPPConnector:
         for i in xrange(100):
             pcfgs.append({"_id": "pcfg_{0}".format(i),
                           "type": "payload_configuration", "i": i})
+        for i in xrange(20):
+            pcfgs.append({"_id": "nonexistant_{0}".format(i)})
         for i in xrange(100):
             payloads = random.sample(pcfgs, random.randint(1, 5))
             doc = {"_id": "flight_{0}", "type": "flight", "i": i,
@@ -758,12 +760,22 @@ class TestCPPConnector:
             end = self.callbacks.fake_rfc3339(2000 + i)
             rows.append({"id": doc["_id"], "key": [end, start, 0],
                         "value": None, "doc": doc})
+
+            expect_payloads = []
             for p in payloads:
+                p_id = p["_id"]
+                if "nonexistant" in p_id:
+                    # nonexistant referenced docs should not be in 
+                    # _payload_docs
+                    p = None
+                else:
+                    expect_payloads.append(p)
+
                 rows.append({"id": doc["_id"], "key": [end, start, 1],
-                            "value": {"_id": p["_id"]}, "doc": p})
+                            "value": {"_id": p_id}, "doc": p})
 
             doc = copy.deepcopy(doc)
-            doc["_payload_docs"] = payloads
+            doc["_payload_docs"] = expect_payloads
             expect_result.append(doc)
 
         fake_view_response = \