The FCC today sent an inquiry (PDF) to Google and the major US carriers to explain their early termination fees (ETFs). Adding Google to an already ongoing debate, the US agency wants the search firm to explain its mystery Equipment Recovery Fee that doubles the cost of canceling Nexus One service early. While it praises Google for offering a new business model, the FCC questions Google's decision to charge an ETF above and beyond T-Mobile's when no other carrier or phone involves that fee.