diff --git a/catalogs/sources/gtfs/realtime/us-arizona-mountain-line-gtfs-rt-sa-1982.json b/catalogs/sources/gtfs/realtime/us-arizona-mountain-line-gtfs-rt-sa-1982.json
index 483719f3..33f8a570 100644
--- a/catalogs/sources/gtfs/realtime/us-arizona-mountain-line-gtfs-rt-sa-1982.json
+++ b/catalogs/sources/gtfs/realtime/us-arizona-mountain-line-gtfs-rt-sa-1982.json
@@ -1,7 +1,9 @@
 {
     "mdb_source_id": 1982,
     "data_type": "gtfs-rt",
-    "entity_type": "sa",
+    "entity_type": [
+        "sa"
+    ],
     "provider": "Mountain Line Transit",
     "static_reference": [
         1979