Q: Can the Imaam sit on a chair and lead taraweeh prayers?
A: Yes the Imam may sit and lead the salaah of a congregation that is standing behind him. However, the condition for this is that the sitting Imam must be able to perform a full sajda. If his sujood is done via movements and indications, then his Imamat will not be valid, even for taraweeh salaah. For taraweeh, the Imam may sit and lead the prayers even if he does not have a valid excuse, but he must make a full sajda. Hence, one who sits on a chair and only makes sujood by inclining forward, will not be able to lead the taraweeh jamaat. Also note that to sit and lead the taraweeh salaah is not preferable, for the reward is halved
And Allah Ta’ala knows best.
Mufti Siraj Desai