diff --git a/demo.py b/demo.py
index 109f6f8..4729a28 100644
--- a/demo.py
+++ b/demo.py
@@ -1,5 +1,6 @@
 #-*- coding: utf-8 -*-
 from manager import Manager
+import datetime
 
 test_manager = Manager() 					# avec proxy
 test_manager = Manager(how_to_auth='cert') 	# avec cert
@@ -11,10 +12,15 @@
     ]
 }
 
+# startTime et endTime peuvent être des objets datetime.datetime ou des str au format AAAA-MM-JJ HH:MM
+# attention : startTime et endTime doivent être exprimées en heures UTC
+startTime=datetime.datetime(year=2019, month=10, day=21, hour=14, minute=30, tzinfo=datetime.timezone.utc)
+endTime=  datetime.datetime(year=2019, month=10, day=21, hour=15, minute=30, tzinfo=datetime.timezone.utc)
+
 # démo queryFlightsByAirspace
 flight_list = test_manager.queryFlightsByAirspace(
     airspace="LFFFTH", 
-    startTime="2019-10-18 17:00", endTime="2019-10-18 18:30",
+    startTime=startTime, endTime=endTime,
     other_params=other_params)
 print(flight_list.data)
 
@@ -22,13 +28,13 @@
 flight_list = test_manager.queryFlightsByAerodrome(
     aerodrome="LFPG",
 	aerodromeRole="DEPARTURE",
-   	startTime="2019-10-18 17:00", endTime="2019-10-18 18:30",
+   	startTime=startTime, endTime=endTime,
 	other_params=other_params)
 print(flight_list.data)
 
 # démo queryFlightsByTrafficVolume
 flight_list = test_manager.queryFlightsByTrafficVolume(
     trafficVolume='LFFTN',
-   	startTime="2019-10-18 17:00", endTime="2019-10-18 18:30",
+   	startTime=startTime, endTime=endTime,
 	other_params=other_params)
 print(flight_list.data)
\ No newline at end of file
diff --git a/manager.py b/manager.py
index cad620c..ca97469 100644
--- a/manager.py
+++ b/manager.py
@@ -114,6 +114,12 @@ def update_params_for_queries(self, new_params):
 			if param in self.params_for_queries:
 				self.params_for_queries[param] = new_params[param]
 	
+	def set_traffic_window(self, startTime, endTime):
+		return {
+			'wef': utils.format_datetime_for_nm(startTime), 
+			'unt': utils.format_datetime_for_nm(endTime)
+		}
+	
 	# -----------------------------------------------------------------------------------------
 	def queryFlightsByAirspace(self, airspace, startTime, endTime, other_params={}):
 		""" Liste des vols par airspace
@@ -132,7 +138,7 @@ def queryFlightsByAirspace(self, airspace, startTime, endTime, other_params={}):
 			dictionnaire pour overrider les valeurs par défaut de _default_params_for_queries
     	"""
 		
-		trafficWindow = {'wef': startTime, 'unt': endTime}
+		trafficWindow = self.set_traffic_window(startTime, endTime)
 		self.update_params_for_queries(other_params)		
 		client = Client(**self.conf, service_name='FlightManagementService')
 		self.tmp_data = client.service.queryFlightsByAirspace(
@@ -159,7 +165,7 @@ def queryFlightsByAerodrome(self, aerodrome, aerodromeRole, startTime, endTime,
 		other_params
 			dictionnaire pour overrider les valeurs par défaut de _default_params_for_queries
     	"""
-		trafficWindow = {'wef': startTime, 'unt': endTime}
+		trafficWindow = self.set_traffic_window(startTime, endTime)
 		self.update_params_for_queries(other_params)
 		client = Client(**self.conf, service_name='FlightManagementService')
 		self.tmp_data = client.service.queryFlightsByAerodrome(
@@ -184,7 +190,7 @@ def queryFlightsByTrafficVolume(self, trafficVolume, startTime, endTime, other_p
 		other_params
 			dictionnaire pour overrider les valeurs par défaut de _default_params_for_queries
     	"""
-		trafficWindow = {'wef': startTime, 'unt': endTime}
+		trafficWindow = self.set_traffic_window(startTime, endTime)
 		self.update_params_for_queries(other_params)
 		client = Client(**self.conf, service_name='FlightManagementService')
 		self.tmp_data = client.service.queryFlightsByTrafficVolume(
diff --git a/utils.py b/utils.py
index fd4fe59..8ab0099 100644
--- a/utils.py
+++ b/utils.py
@@ -1,25 +1,12 @@
 #!/usr/bin/env python
 #-*- coding: utf-8 -*-
 
-import argparse
 import datetime
-import logging
 import os
-import re
-import sys
-import xml.etree.ElementTree as ET
 
-import requests
-#from elasticsearch import Elasticsearch
-
-#from decolog import *
-#from dsnaproxies import dsnaproxies
 from shared_vars import DATA_PATH
 
 
-# -------------------------------------------------------------------
-# -------------------------------------------------------------------
-# Nouveaux utilitaires par Maxence
 def write_content_to_file(filename, content, rep=DATA_PATH):
 	os.makedirs(os.path.dirname(rep+filename), exist_ok=True)
 	full_path = os.path.join(rep, filename)
@@ -39,4 +26,22 @@ def get_datetime(nbr_days=0):
 
 def sendTime():
 	sendTime = f"{datetime.datetime.utcnow().replace(microsecond=0)}"
-	return sendTime[:19]
\ No newline at end of file
+	return sendTime[:19]
+
+def format_datetime_for_nm(datetime_to_format):
+	# TODO : affiner les warnings, messages d'erreurs etc
+	
+	if type(datetime_to_format) == str:
+		# TODO : vérifier que le format correspond bien à ce qui est attendu par NM
+		return datetime_to_format
+	
+	elif isinstance(datetime_to_format, datetime.datetime):
+		if datetime_to_format.tzinfo != datetime.timezone.utc:
+			print("Attention : l'objet datetime.datetime que vous avez passé en argument n'est pas formaté UTC.")
+		return datetime_to_format.strftime("%Y-%m-%d %H:%M")
+	
+	else:
+		print("La date+heure que vous avez passé en argument n'est pas un format \
+			accepté par soapy (str ou objet datetime.datetime).")
+		# TODO rapidement : lever une exception plutôt 
+		exit(1)
\ No newline at end of file