Make yourself a 'Safe start up for complex aircraft'. Start FS go to free flight and 1. select the standard Cessna 172.  2. Select a small unenhanced airport. 3. Open it then ensure that you are on the ground. 4. Turn everything off except 'Avionics'. Save the flight with the name 'Complex Start up' . Go to saved flights and make this your start up scenario when ever you open FS free flight. You can now load any complex aircraft that you have with safety.