In FS9 using the "W" key rotated the view from cockpit interior to outside with instruments displayed along the bottom of the frame, then the a second "W" shifted the view to the same outside view but without the instruments showing. A third "W" returned the view to the cockpit interior.
Is there an equivalent for this in FSX? FSX does show a "W" command in the menu, but clicking on the "W" produces no result (at least for me).
Thanks in advance for any suggestions...

The 'W' key still works in FSX as it did in FS9, switching the 2-D panel display. It didn't/doesn't take you outside the cockpit. It switches between full 2-D panel, mini-panel (primary gauges only), and no panel.

As Buggs explains, the difference in FSX is how you get to the 2-D panel. Press 'S' until your in the 'Cockpit view:' category.  Then 'A' until the 'Cockpit' (2-D panel) displays. The 'W' key will then cycle thru the 2-D panel variations.

Some addon ac may not have 2-D panels. Some aircraft have more 2-D panel variations. For instance, in the default C-172, the 'W' key will cycle the 2-D panel thru; Standard panel, IFR panel, landing panel, mini-panel and no panel.

Dave