Hi Chris,

this is a known problem which could happen sometimes. Here's a copy of my FAQ which should help you:

"I could not start engine 2 and 3."

This could happen if you flew another aircraft before the BAe 146 and you stop the engines with the mixture control, or if you have saved a cold and dark cockpit situation when starting. In this case sometimes the mixture controls of engine 2 and 3 stay closed. There are now two ways to activate them. Either you open the mixture control in another aircraft or you press the keys cntr+shift+F4 when the BAe 146 is loaded to switch on the mixture of engine 2 and 3. Now it should be possible to start all engines. This will be corrected with the next update.

Best Regards
Matthias