Over the last days I have made good progress again with reading aircraft MDL files. I should directly say that not all of them will import correctly at this moment, but more and more are working. And also setting the conditions to extract a landing gear or set the flaps is working much better now. I will keep debugging the aircraft that do not yet work correctly, but this functionality is almost useful now. It can for example be used to make static aircraft out of old flyable aircraft, a task that is currently usually done using the great tool MDLtoBGL by Trevor de Stigter.
While working on reading the aircraft files I have also fixed some bugs in the code that checks the conditions of variables when reading the object. So also people converting scenery objects should see that this works better now.