Tachanun on Yom Kippur:
Tachanun is omitted on Yom Kippur. Hence, the Tachanun and Al Cheit is omitted from Kerias Shema Sheal Hamita and the Ribono Shel Olam and Elokeinu Velokei Avoseinu is omitted from Karbanos.
 Shaareiy Halacha Uminhag 2/258
 The Rebbe Rayatz stated that “Al Cheit” is only said when necessary and we do not add to it. [ibid]