Checkpoint 1.12 - Flash
Progressive disclosure is used for Flash movies with complex controls
WCAG 1.0 Priority 3
WCAG Guideline 13. Provide clear navigation mechanisms.
It could be very difficult for screen reader and keyboard-only users to navigate Flash content with numerous links and complex controls, especially if these links and controls are provided on every page.
Providing a progressive disclosure of the content might where the user is allowed to drill down the content when they choose to, will alleviate this problem.
Hide multiple controls under a single control to reduce complexity of the overall navigation.
Specify shortcut names through the Flash Accessibility Panel and enable the shortcut key with Action Script.
Tab through the Flash content to ensure it is not too complex and drill down navigation mechanisms are available.
The original source of this information is located on the W3C web site (www.w3.org/TR/WCAG10-TECHS/#tech-group-links)