diff --git a/src/server/BreCal/database/enums.py b/src/server/BreCal/database/enums.py
index 7cab2d0..372b760 100644
--- a/src/server/BreCal/database/enums.py
+++ b/src/server/BreCal/database/enums.py
@@ -11,10 +11,6 @@ class ParticipantType(IntFlag):
     PORT_ADMINISTRATION = 32
     TUG = 64
 
-    @classmethod
-    def _missing_(cls, value):
-        return cls.undefined
-
 class ShipcallType(IntEnum):
     """determines the type of a shipcall, as this changes the applicable validation rules"""
     undefined = 0
@@ -67,6 +63,3 @@ class ParticipantFlag(IntFlag):
     undefined = 0
     BSMD = 1
 
-    @classmethod
-    def _missing_(cls, value):
-        return cls.undefined
diff --git a/src/server/BreCal/impl/times.py b/src/server/BreCal/impl/times.py
index 8c9f0e8..9b0fe56 100644
--- a/src/server/BreCal/impl/times.py
+++ b/src/server/BreCal/impl/times.py
@@ -83,6 +83,7 @@ def PostTimes(schemaModel):
             query += "?" + key + "?"
         query += ")"
 
+        logging.error(f"(/impl/times @86 issue:) query: {query}, schemaModel: {schemaModel}")
         commands.execute(query, schemaModel)
         new_id = commands.execute_scalar("select last_insert_id()")
 
diff --git a/src/server/BreCal/validators/input_validation_times.py b/src/server/BreCal/validators/input_validation_times.py
index e2c01ef..0385220 100644
--- a/src/server/BreCal/validators/input_validation_times.py
+++ b/src/server/BreCal/validators/input_validation_times.py
@@ -27,8 +27,8 @@ def build_post_data_type_dependent_required_fields_dict()->dict[ShipcallType,dic
     """
     post_data_type_dependent_required_fields_dict = {
         ShipcallType.arrival:{
-            ParticipantType.undefined:None, # should not be set in POST requests
-            ParticipantType.BSMD:None, # should not be set in POST requests
+            ParticipantType.undefined:[], # should not be set in POST requests
+            ParticipantType.BSMD:[], # should not be set in POST requests
             ParticipantType.TERMINAL:["operations_start"],
             ParticipantType.AGENCY:["eta_berth"],
             ParticipantType.MOORING:["eta_berth"],
@@ -37,8 +37,8 @@ def build_post_data_type_dependent_required_fields_dict()->dict[ShipcallType,dic
             ParticipantType.TUG:["eta_berth"],
         },
         ShipcallType.departure:{
-            ParticipantType.undefined:None, # should not be set in POST requests
-            ParticipantType.BSMD:None, # should not be set in POST requests
+            ParticipantType.undefined:[], # should not be set in POST requests
+            ParticipantType.BSMD:[], # should not be set in POST requests
             ParticipantType.TERMINAL:["operations_end"],
             ParticipantType.AGENCY:["etd_berth"],
             ParticipantType.MOORING:["etd_berth"],
@@ -47,8 +47,8 @@ def build_post_data_type_dependent_required_fields_dict()->dict[ShipcallType,dic
             ParticipantType.TUG:["etd_berth"],
         },
         ShipcallType.shifting:{
-            ParticipantType.undefined:None, # should not be set in POST requests
-            ParticipantType.BSMD:None, # should not be set in POST requests
+            ParticipantType.undefined:[], # should not be set in POST requests
+            ParticipantType.BSMD:[], # should not be set in POST requests
             ParticipantType.TERMINAL:["operations_start", "operations_end"],
             ParticipantType.AGENCY:["eta_berth", "etd_berth"],
             ParticipantType.MOORING:["eta_berth", "etd_berth"],
@@ -270,7 +270,8 @@ class InputValidationTimes():
         dependent_required_fields_dict = build_post_data_type_dependent_required_fields_dict()
 
         # select shipcall type &  participant type
-        dependent_required_fields = dependent_required_fields_dict.get(shipcall_type,{}).get(participant_type,None)
+        dependent_required_fields = dependent_required_fields_dict.get(shipcall_type,{}).get(participant_type,[])
+        dependent_required_fields = dependent_required_fields if dependent_required_fields is not None else []
         return dependent_required_fields
     
     @staticmethod
diff --git a/src/server/BreCal/validators/input_validation_utils.py b/src/server/BreCal/validators/input_validation_utils.py
index a78a75a..e68f18e 100644
--- a/src/server/BreCal/validators/input_validation_utils.py
+++ b/src/server/BreCal/validators/input_validation_utils.py
@@ -20,7 +20,8 @@ def get_participant_id_dictionary():
 
     # build a dictionary of id:item pairs, so one can select the respective participant
     participants = json.loads(response)
-    participants = {items.get("id"):items for items in participants}
+    participants = {items.get("id"):{**items, "participant_id":items.get("id")} for items in participants}
+    assert all(["participant_id" in participant for k,participant in participants.items()])
     return participants
 
 def get_berth_id_dictionary():