Steve,

What Claude is referring to is slightly different.  He isn't talking about the initial load of the scenario, he is talking about using some of the new, advanced capabilities embedded in Prepar3D that allow you to "slew and do" repeatedly by use of rapid reposition of the airplane. 

There is a product that some users are installing that provides this functionality in a nice "Sim-Like" fashion, but it doesn't play well with our products because we aren't using the default simulator processes underneath.  This causes the airplane to get out of sync with the platform and causes software faults/ctds.

Figuring that out can be done through a massive research investment, or dumbing down our products to make them use only the default platform's data...

 

That's right Rob, I quite agree. However I was responding to the comment from the initial OP and tried to help serviceceiling on his query about it.

On ‎23‎/‎10‎/‎2017 at 5:11 PM, serviceceiling said:

Nope. I had addon aircraft set as default for ages. From the A2A Cessna, to the PMDG 777, Aerosoft Airbus or the Majestic Q400 now. Never had any problems. 

I tried one of your sample set and true enough the aircraft could be saved in a flight file and enabled as the default flight file without causing problems even when loading other aircraft after. So in the current context we would class this as a 'simple aircraft' safe to use in a default flight. Which is the point others are making about starting the sim with a default flight. Some aircraft may not be so friendly saved in the default flight file and so classed as a 'complex aircraft' in this context. Your experience is what most expect and  most get. I hope that helps.