FCC Chairman Julius Genachowski said to be leaving agency FCC Chairman Julius Genachowski is leaving his post, according to a person familiar with the matter, setting up a second vacancy on the five-member board of the U.S. agency that regulates telephone, cable and broadcast companies. Genachowski, a Democrat, will announce his departure from the Federal Communications Commission on Friday, said the person, who asked not to be named in discussing a personnel matter. Neil Grace, an FCC spokesman, declined to comment. To replace the 50-year-old Genachowski, President Obama could elevate either of the agency's two Democrats or name a chairman from two new members who will need Senate confirmation. Genachowski can depart without leaving behind a 2-2 partisan tie because Republican Robert McDowell announced Thursday that he'll resign in the coming weeks. The changes will leave Mignon Clyburn and Jessica Rosenworcel as the FCC's Democrats, and Ajit Pai as its sole Republican. With two seats open on the FCC, the administration can advance a Republican and a Democratic nominee simultaneously, making it easier for both to win approval from the Senate, said Andrew Lipman, a Washington partner at Boston's Bingham McCutchen law firm. Genachowski's focus on expanding access to high-speed wireless Internet service, or mobile broadband, broke with some priorities of his predecessors. His FCC levied no fines for broadcast indecency after a flurry of penalties under Republican chairmen from 2003 to 2008, and he didn't complete a loosening of media-ownership rules. Tasks awaiting the FCC's new leader include conducting an auction to free airwaves for use by high-speed wireless Internet service. The auction, which could take place next year, would sell access to airwaves voluntarily relinquished by television stations, and pay the broadcasters for giving up their frequencies. Freeing airwaves is one way to relieve a spectrum shortage, an issue that Genachowski made a touchstone of his chairmanship. In a 2009 speech he warned of a "looming spectrum crisis" and he repeatedly drew attention to the need for more airwaves to help handle increasing wireless traffic as Americans move toward mobile computing via smartphones and tablets. Policy questions include whether to restrict participation in the auction by the largest U.S. wireless carrier, Verizon Wireless, and second-largest, AT&T Inc., to ensure that smaller companies capture enough airwaves to remain competitive. The FCC also must decide how many airwaves to reserve for Wi-Fi-like services that can provide access to the Internet without going through a traditional wireless carrier. The auction could yield 120 megahertz of airwaves for wireless use, according to the National Broadband Plan that Genachowski guided to completion in 2010. That amount is almost one-quarter of the airwaves Obama set as a national goal. In 2011, Genachowski and the Obama administration opposed AT&T's bid for T-Mobile USA Inc., the nation's fourth-largest mobile carrier, saying it would reduce competition. AT&T, under pressure, abandoned the $39-billion deal. Blocking the deal helped spur wireless competition by preserving T-Mobile as a competitor and by protecting the third-largest carrier, Sprint Nextel Corp., from being overwhelmed by a new behemoth, said Reed Hundt, a former FCC chairman. Tokyo mobile carrier Softbank Corp. is seeking to buy Sprint, which wouldn't have otherwise happened, Hundt said. On March 13, Genachowski's FCC approved T-Mobile's combination with fifth-largest carrier MetroPCS Communications Inc. On Wednesday, Genachowski said the agency's review of Softbank's $20-billion bid for Sprint was on track for completion by late May.