The FAA assumed that its chosen ADS-B program bidders–Lockheed Martin, ITT and Raytheon–would submit competitive offers on the expected system configuration. This service would be provided to GA through the FAA-developed 978 MHz UAT system, and to other users through the internationally standardized 1090 MHz frequency. More than 500 dual-frequency ground stations nationwide would “translate” incoming UAT signals to 1090 MHz and rebroadcast them, alerting 1090 MHz users to a UAT aircraft’s presence, and vice versa. Raytheon has proposed that GA drop UAT and adopt 1090 MHz, permitting worldwide ADS-B access (UAT is unique to the NAS) and allowing removal of legacy mode-A/C transponders. The plan needs only single-frequency ground stations, which sources tell AIN could save more than $200 million of the estimated $1 billion program cost. The FAA’s dilemma is whether it should reject Raytheon’s bid, since it changes the contract’s concept, or whether its potential savings make it admissible as an “innovative solution,” which the agency encouraged bidders to submit. A decision is imminent.