{mosads}They demanded all of the FCC’s internal documents on LightSquared, including test results and communications with the company, its investors or GPS companies.

They also requested information from the Defense Department, the National Telecommunications and Information Administration and the National Space-Based Positioning, Navigation and Timing Executive Committee.

In a press release, the lawmakers said they believe a “comprehensive review of the FCC” is needed to determine why the agency did not better handle the interference issues.

Sen. Chuck Grassley (R-Iowa) has demanded the same information from the FCC for months and is holding up President Obama’s nominees to the commission over the issue.

FCC officials have said the usual order of business is to only comply with requests from committees that have jurisdiction over their agency. Although Grassley does not serve on any of those committees, the Energy and Commerce Committee is the House panel that oversees the FCC.

Energy and Commerce is the same committee leading the investigation of the administration’s support for failed solar panel firm, Solyndra.

Republicans have questioned whether the FCC and the White House have shown inappropriate favoritism to LightSquared. Last September, Rep. Michele Bachmann (R-Minn.) accused Obama of “crony capitalism” for allegedly giving favor to his political supporters, pointing to Philip Falcone, who has invested billions of dollars in the company. 

Falcone has donated to both Democrats and Republicans in recent years and says he is a registered Republican. He has denied any attempts to influence the process through political connections. 

The White House and the FCC have denied giving any special treatment to LightSquared, but expanding broadband access has been a top priority for both agencies. 

LightSquared CEO Sanjiv Ahuja resigned on Tuesday. The company said it plans to continue to fight for regulatory approval.

Testing showed that LightSquared’s signal does not bleed into the GPS band. Instead, the problem is that GPS receivers are too sensitive to filter out LightSquared’s powerful cell towers operating on nearby frequencies.

LightSquared say that it is the GPS industry’s responsibility to build receivers that only listen to their own designated frequencies, but GPS companies argue that LightSquared is trying to build a cellphone network relying on frequencies that should only be used by satellites, which transmit much fainter signals.