I recall it was replaced in the early/mid 70's by a 4th Edition (?) ... which came in a small blue plastic ring-binder if my memory serves me correctly (which was difficult to stuff in the leg pocket of your flying suit unlike the earlier editions !) ... by which time the Carb Air setting was declared "wired hot"
"Carb Air" was certainly Wire-locked 'Hot' by end 1969. Anybody know what actually precipitated this?
(one presumes to make it "idiot proof" against carb-air icing, but was there an actual incident?)