In reading the report into the crash of UPS Flight 6, I noticed that one of the items of feedback from pilots in a simulated inflight-fire scenario utilising a smoke-filled simulator was (page 287 of the report):
In the thickest smoke, only Braille will help. What bigger font does to you, if there is any "break" in the smoke, it allows you to see more letters (group), therefore part of words. From that you can deduct what the action on the checklist is for the next step.
Which makes sense, as Braille, unlike most scripts, is read by touch rather than by sight, and is, thus, unaffected by limited or nonexistent cockpit visibility, while visual scripts, even with large, simple glyphs, have their legibility severely impaired by a smoky cockpit (in dense smoke, the pilot(s) essentially have to wait to do anything until the smoke momentarily lifts), and are completely useless in a zero-visibility environment.
With this in mind, do any airlines (passenger and/or cargo) have Braille checklists for use in situations of severely degraded cockpit visibility (such as a cockpit filled to the brim with dense black smoke)?