In 2008, then-Chancellor Michelle A. Rhee turned over a third of the city’s public school principal posts, reassigning some leaders and hiring what the head of New Leaders for New Schools, a recruiting nonprofit, called “an army of believers.”

But struggling urban school systems chew up principals. With each successive spring, more members of the DCPS 2008 cohort have moved on through resignation, retirement, termination for poor academic performance or other issues. Officials never spell out the exact reasons, and few of those moving on ever talk.

DCPS confirmed Tuesday that at least 17 school leadership jobs will change this year. They include three more members of the class of 2008: Michael Johnson of Phelps Architecture, Construction and Engineering HS; Tanishia Williams-Minor of Washington Metropolitan HS; and Margaret Stephens-Aliendre of Moten Elementary@Wilkinson. By my count, that makes 28 of the 46 — about 60 percent — who are no longer in the schools where Rhee placed them. (This tally does not include Brian Betts, the Shaw Middle School@Garnet-Patterson principal who was murdered in 2010). While a few have moved into senior administrative posts or to other schools, most left the system.

Principal attrition under Chancellor Kaya Henderson is not as heavy as in the Rhee era. The 17 changes represent about 14 percent of the system’s principal posts. But the churn is considerable compared to Montgomery County Public Schools, where the 10 percent turnover in 2011 (the most recent year available) was “unusually high,” according to spokesman Dana Tofig. For the previous three years, he said, turnover was between 5 and 6 percent.

Also among this year’s D.C. departures are some veteran school leaders, including Katie Jones of Winston Education Campus, Gwendolyn Grant of Cardozo HS and Angela Tilghman of Garfield Elementary, a 2004 winner of The Post’s Distinguished Educational Leadership Award for her work at Miner Elementary.

Other schools or programs losing principals are:

Aiton Elementary: Irina Malykhina

Ballou STAY: Wilbert Miller

Brookland EC@Bunker Hill Education Campus: Donna Pressley

Browne EC: Rashida Tyler

Garrison ES: Rembert Seaward

Langdon EC: Barbara Campbell

Prospect Learning Center: Keesha Blythe

Seaton ES: Douglas Rice

Shaw MS@Garnet-Patterson: Kimberly Douglas

Walker-Jones EC: Melissa Martin

H.D. Woodson HS: Thomas Whittle.

An 18th school, Deal Middle School, has been operating with an interim principal, James Albright, since the departure of Melissa Kim last fall. Albright is a candidate for the permanent post, DCPS said Tuesday.