Hilchot Asara Be-Tevet which Falls on Friday

Q: Is it possible for a fast day to fall on a Friday?

A: Asara Be-Tevet is the only one.  Shulchan Aruch, Orach Chaim 428, 550.

Q: Is it permissible to eat before Alot Ha-Shachar?

A: Yes, if one made such a condition before going to sleep, and it is sufficient to think it (Shulchan Aruch, Orach Chaim 564:1.  Mishnah Berurah #3.  Sha'ar Ha-Tziyun #3).

Q: It is permissible to brush one's teeth?

A: Yes (Shut Minchat Yitzchak 4:109.  Yalkut Yosef – Moadim, p. 534).

Q: To bathe?

A: Even one who is strict not to bathe on Asara Be-Tevet may do so when it falls on Friday in honor of Shabbat (Mishnah Berurah 550:6.  Shut Yechaveh Daat 5:41).

Q: Can someone who is not fasting serve as Shaliach Tzibur?

A: No.  Shulchan Aruch 566:2.

Q: It there a Minhag to give Tzedakah?

A: Yes.  The reward of a fast is the Tzedakah given.  Berachot 6b.  And there are those who give the amount of food they would have eaten.  Mishnah Berurah 566:12.

Q: Is it permissible to taste the food in honor of Shabbat if there is a concern that the taste will be spoiled?

A: Taste a tiny amount and spit it out.  Rama, Orach Chaim 557:1.  Mishnah Berurah #6.

Q: Should one also put on Talit and Tefillin at Minchah?

A: The majority do not put on Tefillin at Minchah.  Sha'arei Teshuvah 34:2, 37:1.  Biur Halachah 37 d.h. Be-Sha'at.  Regarding Talit, there is no problem to do so.

Q: If the community Davens after sundown, do they still read the Torah reading of Vayechal and say Anenu in the Shemoneh Esrei?

A: Yes.  But they should take care to Daven before sundown since there is a belittling of the honor of Shabbat in doing so (Shut Dvar Yehoshua 3:63.  Piskei Teshuvot 550:10).

Q: Do we recite Birchat Cohanim at Minchah (in Eretz Yisrael)?

A: Some say in the name of the Chazon Ish that a Cohain who is fasting recites Birchat Cohanim even at Minchah Gedolah, and this is how they act in his Beit Midrash in Bnei Brak (Kehilat Yaakov Bereachot #29.  Maaseh Ish Vol. 2, p. 98), and some also follow his ruling in other places (Moadim Uzmanim 7:248).  But this is an innovation.  In general, we only recite Birchat Cohanim at Minchah Ketana (Shut Shevet Ha-Levi 8:23.  Hilchot Shlomo, Chapter 10 note 21).  And some say only after Pelag Ha-Minchah (Luach Eretz Yisrael).  See Piskei Teshuvot (128:1) and Ishei Yisrael (Chapter 27 note #116).

Q: Do we recite Vidui and Tachanun at Minchah?

A: No (Mishnah Berurah 550:11).  And the same is true of Avinu Malchenu (Mishnah Berurah 602:3), and some Sefaradim recite Avinu Malchenu skipping the parts which mention sin (see Shut Yechaveh Daat 1:54.  Piskei Teshuvot 550 note #37).

Q: When does the fast end?

A: After three medium size stars have come out on Shabbat.  Rama, Orach Chaim 249:4.