ABSTRACT
Safety-critical displays must either be completely invulnerable to failures or must have a backup display. A display may fail for various reasons and cause various degrees of information loss. A backup display might merely duplicate the primary one or present supplemental information until it needs to serve in the primary role. In certain aviation applications, an integrated standby instrument system serves as the backup to the primary flight display in so-called glass cockpits. Pilots are encouraged to fly using the backup display on occasion so that they are better prepared to rely on it in case of a primary display failure. If a display communicates critical information, provide a backup display to ensure that users have access to critical information in the event the primary display fails. One exception to the backup rule could be when a critical display failure is part of a larger-scale failure that renders the displayed information useless.
