It’s the first day of school for chancellor-in-waiting Cathie Black.

The morning after receiving permission from the state to make Black the city’s new schools chief, Mayor Michael Bloomberg is taking her to meet some of the students and teachers who will soon be in her charge. Bloomberg and Black, along with Deputy Mayor Dennis Walcott, will greet parents and students as they arrive at PS 109 in the Bronx.

Home to a gifted program, PS 109 is one of the top-performing elementary schools in District 9, scoring an A on its most recent progress report and getting extra credit for boosting its weakest students’ test scores. Principal Amanda Blatter brought a focus on accountability to the school, according to Insideschools, which also reports that 16 teachers left the school during Blatter’s first two years at PS 109.

Black’s visit marks the first time she has appeared in public since Bloomberg surprised the city earlier this month by picking her to replace outgoing Chancellor Joel Klein. Black lives on Park Avenue, attended parochial school, and sent her children to boarding school, but today won’t be her first time in a Bronx public school — she was an honorary principal of IS 125 for a day in April 2000.

Conspicuously missing from the city’s press release about today’s school visit: Shael Polakow-Suransky, who is set to become Black’s chief academic officer. His promotion was key to Black’s waiver, but Bloomberg swore yesterday that Black alone would run the school system.