As mentioned above, I would highly recommend that you locate your Default Beech Air King in the FS 2004 CD's, and reinstall it....

...!
There will come a time when you will require it; (Multiplayer Flights, etc).
Missing Default Aircraft can cause all sorts of problems...(Missing Panels, Sounds, etc)...

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Paul...G-BPLF... 8-)...!
Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.