The Nation’s air traffic controllers play an important role in maintaining the world’s safest air transportation system. Yet, losses of standard separation when aircraft do not maintain the minimum distance apart remain a significant safety concern.

At any given time, there are roughly 7,000 aircraft occupying U.S. airspace. To help maintain safe distances between aircraft, while under the control of air traffic controllers, the FAA established minimum separation standards based on the aircraft’s phase of flight and size. Controllers are responsible for providing instructions to pilots.

In January 2011, an operational error a loss of standard separation caused by air traffic controllers led to a near mid-air collision between a commercial airliner and two military aircraft near New York City.

According to the National Transportation Safety Board (NTSB), who investigated the incident, at their closest point, the aircraft came within a mile of each other. According to the Federal Aviation Administration (FAA) statistics, the number of reported operational errors increased by more than 50 percent between fiscal years 2009 and 2010.

Concerned with this increase, the Senate Committee on Commerce, Science, and Transportation and the Subcommittee on Aviation Operations, Safety, and Security requested that Department of Transportation’s (DOT) Office of Inspector General (OIG) reviewed the FAA’s ongoing efforts to assess operational errors and mitigate their risks.

OIG also received a similar request from the House Committee on Transportation and Infrastructure. Accordingly, OIG identified the reasons for the increase in losses of separation specifically operational errors from fiscal years 2009 to 2010, assessed the effectiveness of the FAA’s policies and processes to collect, investigate, and report separation losses; and evaluated the effectiveness of FAA’s policies and processes to mitigate the risk of separation losses.

According to the FAA, the dramatic increase in reported operational errors between fiscal years 2009 and 2010 was mostly due to increased reporting through programs such as the Air Traffic Safety Action Program (ATSAP) and the Traffic Analysis and Review Program (TARP), an automated system to detect losses of separation at air traffic terminal facilities.

OIG found that the increase in reported errors was linked, in part, to a rise in actual errors rather than increased reporting. For example, the FAA’s air route traffic control centers (ARTCC) which have had an automated system in place for years to detect and investigate reported errors had a 39 percent increase in operational errors during the same period.

In addition, OIG identified other contributing factors to the rise in the number of operational errors. For example, almost one quarter of the increase is due to the revocation of a separation waiver at the Southern California Terminal Radar Approach Control (TRACON) that led to the reclassification of many routine approach and landings as operational errors.

The FAA’s new policies and procedures for collecting, investigating, and reporting separation losses have the potential to reduce losses and improve reporting, but their effectiveness is limited by incomplete data and implementation challenges. Under the FAA’s new policies, the FAA uses TARP to detect losses, then examines the risk of these losses, and identifies corrective actions. OIG found that the effectiveness of these procedures is limited by incomplete data and implementation challenges. Finally, the FAA has recently developed new corrective action plans to mitigate high-risk separation loss events.

However, it is too early to determine the effectiveness of these plans. In addition, the Agency’s corrective action plans do not include all safety risks identified by the FAA and will not address all losses of separation that air traffic facility officials consider to be high risk. The FAA concurred with four and partially concurred with two of OIG’s six recommendations to improve the Agency’s policies and processes for identifying and mitigating separation losses.

Department of Transportation’s Office of Inspector General has made recommendations To improve the FAA’s policies and processes for collecting, investigating, and reporting separation losses, and mitigating their risks, OIG recommend that the FAA:

1. Include all losses of separation that are reported under ATSAP, but unknown to air traffic facilities, in its official count of such events.

2. Determine the level of staff and expertise needed at the ATO Service Areas to effectively implement ATO’s new Orders on investigating losses of separation, audit all TARP data, and initiate actions to fill those requirements.

3. Determine the extent to which ATO has successfully implemented its new orders (effective January 2012). This determination should include reviews of the quality of separation loss investigation reports, effectiveness of training, and additional actions or resources needed.

4. Include high-risk TCAS warning events in its Risk Analysis Process and System Risk Event Rate when the separation between two converging aircraft is maintained at 66 percent or more.

5. Develop actions to mitigate the following situations identified in the Risk Analysis Process: (1) poor recovery from loss of separation and (2) losses of separation involving on-the-job training.

6. Utilize analysis of the causal and contributory factors derived in the Risk Analysis Process including perception, memory, and training to identify the underlying reasons for separation losses and develop mitigation strategies to address those causes.

Please view the original article at Aviation Online magazine.