Lingering uncertainty about whether cellphone calls placed by airline passengers would cause interference with the cell system on the ground has prompted the Federal Communications Commission (FCC) to drop a longstanding proposal to relax the current ban. FCC chairman Kevin Martin said it’s unclear at this point whether cellphone calls placed from aircraft would contact multiple cell towers simultaneously, which can disrupt the overall system. Technology has been developed to prevent such interference, but cellular providers have told the commission that technical and engineering issues have yet to be resolved. As a result, Martin wants the FCC to keep the cellphone ban in place for now. This might not be the end of the story, however. So-called Wi-Fi smartphones for the consumer market are on the way. Unlike traditional cellphones, smartphones use available wireless Internet connections to route calls. Passengers one day might be allowed to use these phones on aircraft fitted with onboard Wi-Fi connections without violating the FCC’s rules, according to industry insiders. If the technology can be proved safe, the FAA is likely to allow the use of smartphones.