Meanwhile, important signs of progress are finally emerging on another key FAA effort, the ERAM program. This has been among the agency's most troubled—and most expensive—projects in recent years, and the agency has been frequently lashed by congressional lawmakers and government watchdog agencies for the problems in ERAM.

ERAM is aimed at replacing the backbone operating system used in the FAA's 20 en-route centers. It actually predates the NextGen program, as the contract to build the new system was awarded to Lockheed Martin in 2002. However, it is considered an essential building block for NextGen, since it will be needed for many of the new technologies and procedures being planned.

The new system was originally supposed to be operational at all centers by the end of 2010, at a cost of about $2 billion. It was first deployed to the Salt Lake City and Seattle centers in June and September, 2009, but problems arose during operational trials. These sites were finally declared ready for continuous operations in late 2010, but further deployments did not occur for another year.

In June 2011, the program was re-baselined. The new target for completion is 2014, a slip of almost four years from the original timetable. The cost estimate was increased by $330 million.

The FAA appears to be adhering to its revised plan. Three additional centers—Denver, Minneapolis and Albuquerque—reached initial operating capability (IOC) with ERAM in December 2011, and Chicago, Los Angeles and Oakland centers followed in January 2012. IOC allows operational use for limited periods, and all of these centers except Chicago have now achieved continuous operation status, which means ERAM is used full-time.

Houston achieved IOC in April, and the latest wave of IOCs occurred during the fall in Kansas City, Indianapolis, Boston and New York.

So that means that ERAM is operating in some capacity at 13 of the 20 centers, and is in full-time operation at seven. The target is to have all at least at the IOC stage by the end of 2013. While this may appear to be steady progress, questions persist about whether all the technical problems with ERAM have been resolved.

One of the biggest critics of ERAM has been the Transportation Department's Office of the Inspector General. The OIG has for many years chronicled the problems with ERAM, and faulted the FAA's management of the program.

Even now, the OIG does not believe ERAM is out of the woods. At a congressional hearing in September, Inspector General Calvin Scovel said hundreds of software issues have been revealed during operational trials that still need to be addressed. Scovel concedes that while the FAA is making progress in deployment, “it has not fully resolved critical software-related issues.”

Analysis by the IG's office shows that further delays are possible, and that the cost overrun could be closer to $500 million rather than the $330 million estimated by the FAA.