diff --git a/src/controllers/environment.py b/src/controllers/environment.py
index 3b5b075..15deb0a 100644
--- a/src/controllers/environment.py
+++ b/src/controllers/environment.py
@@ -36,10 +36,8 @@ async def get_rocketpy_environment_binary(
         Raises:
             HTTP 404 Not Found: If the env is not found in the database.
         """
-        env_retrieved = await self.get_environment_by_id(env_id)
-        env_service = EnvironmentService.from_env_model(
-            env_retrieved.environment
-        )
+        env = await self.get_environment_by_id(env_id)
+        env_service = EnvironmentService.from_env_model(env.environment)
         return env_service.get_environment_binary()
 
     @controller_exception_handler
@@ -58,8 +56,6 @@ async def get_environment_simulation(
         Raises:
             HTTP 404 Not Found: If the env does not exist in the database.
         """
-        env_retrieved = await self.get_environment_by_id(env_id)
-        env_service = EnvironmentService.from_env_model(
-            env_retrieved.environment
-        )
+        env = await self.get_environment_by_id(env_id)
+        env_service = EnvironmentService.from_env_model(env.environment)
         return env_service.get_environment_simulation()
diff --git a/src/controllers/flight.py b/src/controllers/flight.py
index ac8624a..9b30398 100644
--- a/src/controllers/flight.py
+++ b/src/controllers/flight.py
@@ -82,10 +82,8 @@ async def get_rocketpy_flight_binary(
         Raises:
             HTTP 404 Not Found: If the flight is not found in the database.
         """
-        flight_retrieved = await self.get_flight_by_id(flight_id)
-        flight_service = FlightService.from_flight_model(
-            flight_retrieved.flight
-        )
+        flight = await self.get_flight_by_id(flight_id)
+        flight_service = FlightService.from_flight_model(flight.flight)
         return flight_service.get_flight_binary()
 
     @controller_exception_handler
@@ -105,8 +103,6 @@ async def get_flight_simulation(
         Raises:
             HTTP 404 Not Found: If the flight does not exist in the database.
         """
-        flight_retrieved = await self.get_flight_by_id(flight_id=flight_id)
-        flight_service = FlightService.from_flight_model(
-            flight_retrieved.flight
-        )
+        flight = await self.get_flight_by_id(flight_id)
+        flight_service = FlightService.from_flight_model(flight.flight)
         return flight_service.get_flight_simulation()
diff --git a/src/controllers/motor.py b/src/controllers/motor.py
index e446cef..3483c1b 100644
--- a/src/controllers/motor.py
+++ b/src/controllers/motor.py
@@ -36,8 +36,8 @@ async def get_rocketpy_motor_binary(
         Raises:
             HTTP 404 Not Found: If the motor is not found in the database.
         """
-        motor_retrieved = await self.get_motor_by_id(motor_id)
-        motor_service = MotorService.from_motor_model(motor_retrieved.motor)
+        motor = await self.get_motor_by_id(motor_id)
+        motor_service = MotorService.from_motor_model(motor.motor)
         return motor_service.get_motor_binary()
 
     @controller_exception_handler
@@ -54,6 +54,6 @@ async def get_motor_simulation(self, motor_id: str) -> MotorSimulation:
         Raises:
             HTTP 404 Not Found: If the motor does not exist in the database.
         """
-        motor_retrieved = await self.get_motor_by_id(motor_id)
-        motor_service = MotorService.from_motor_model(motor_retrieved.motor)
+        motor = await self.get_motor_by_id(motor_id)
+        motor_service = MotorService.from_motor_model(motor.motor)
         return motor_service.get_motor_simulation()
diff --git a/src/controllers/rocket.py b/src/controllers/rocket.py
index a7dcb4d..f586ccc 100644
--- a/src/controllers/rocket.py
+++ b/src/controllers/rocket.py
@@ -33,10 +33,8 @@ async def get_rocketpy_rocket_binary(self, rocket_id: str) -> bytes:
         Raises:
             HTTP 404 Not Found: If the rocket is not found in the database.
         """
-        rocket_retrieved = await self.get_rocket_by_id(rocket_id)
-        rocket_service = RocketService.from_rocket_model(
-            rocket_retrieved.rocket
-        )
+        rocket = await self.get_rocket_by_id(rocket_id)
+        rocket_service = RocketService.from_rocket_model(rocket.rocket)
         return rocket_service.get_rocket_binary()
 
     @controller_exception_handler
@@ -56,8 +54,6 @@ async def get_rocket_simulation(
         Raises:
             HTTP 404 Not Found: If the rocket does not exist in the database.
         """
-        rocket_retrieved = await self.get_rocket_by_id(rocket_id)
-        rocket_service = RocketService.from_rocket_model(
-            rocket_retrieved.rocket
-        )
+        rocket = await self.get_rocket_by_id(rocket_id)
+        rocket_service = RocketService.from_rocket_model(rocket.rocket)
         return rocket_service.get_rocket_simulation()
diff --git a/src/models/flight.py b/src/models/flight.py
index 44ac16a..93d36d4 100644
--- a/src/models/flight.py
+++ b/src/models/flight.py
@@ -34,6 +34,7 @@ def get_additional_parameters(self):
             if value is not None
             and key
             not in [
+                "flight_id",
                 "name",
                 "environment",
                 "rocket",
diff --git a/src/utils.py b/src/utils.py
index 0a8ba45..d31d747 100644
--- a/src/utils.py
+++ b/src/utils.py
@@ -16,7 +16,7 @@ def to_python_primitive(v: Any) -> Any:
 
     Args:
         v: Any value, particularly those with a 'source' attribute
-           containing numpy arrays or generic types.
+       containing numpy arrays or generic types.
 
     Returns:
         The primitive representation of the input value.
@@ -29,6 +29,13 @@ def to_python_primitive(v: Any) -> Any:
             return v.source.item()
 
         return str(v.source)
+
+    if isinstance(v, (np.generic,)):
+        return v.item()
+
+    if isinstance(v, (np.ndarray,)):
+        return v.tolist()
+
     return str(v)