Qwest Chairman and CEO Richard Notebaert took the industry by surprise this morning, announcing his retirement. The 59-year-old executive, who earlier surprised the industry by taking the Qwest job at a time when the scandal-ridden company was poised on the brink of bankruptcy, is the third major executive to leave Qwest this spring.

Two other executives, both of whom worked with Notebaert at Ameritech and were recruited by him to Qwest, had earlier resigned. Oren Shaffer resigned as vice chairman and CFO effective April 1 and was replaced by John W. Richardson, who had been controller and a senior vice president of finance. Barry K. Allen steps down as executive vice president of operations as of June 29 and will be replaced by Robert Tregemba, a vice president of network operations and engineering.

Notebaert did not give a time table for his resignation and said he would remain at the company while the board seeks his replacement.

Notebaert and his team are credited with restoring Qwest’s financial health--in 2006, the company posted its first operating profit since acquiring U S West in 2000. Their departure raises key questions about Qwest’s future, however, and Qwest shares were down in trading today.

Notebaert had installed fiscal discipline at Qwest while greatly improving its customer satisfaction ratings and extending the reach of its broadband services. One key area left unresolved, however, is what Qwest will do with IPTV deployment, which other telecom providers, small and large, are pressing forward on.

In his written statement announcing the resignation, Notebaert said he was retiring to spend more time with his family and “focus on other commitments.”

Notebaert also is the third leader of a former Bell company to step down within the last year. Edward Whitacre stepped down earlier this spring at AT&T and Duane Ackerman retired from BellSouth, when it was acquired by AT&T.