Should the One Who calls the Iqamah lead the Prayer?
Question :
Is it permissible for the Mu'aththin, after calling the Iqamah, to lead the worshippers in prayer?
Answer:
Yes, it is permissible to for one person to fulfill the offices of Mu'aththin and Imam. If the Mu'aththin is more knowledgeable in recitation than others, then he should lead the congregation. Likewise, if the regular Imam is absent and he deputizes him to take his place, just as it is permissible for him to be employed as the regular Imam.
Source:
Ibn Jibreen
Fatawa Islamiyah, Vol. 2 Pages 130