Controller operational errors are on the rise, according to a February 27 audit report from the DOT’s Office of the Inspector General (IG), prompted by requests from the Senate subcommittee on aviation operations, safety and security and, separately, the House Committee on Transportation and Infrastructure. According to FAA data, controller operational errors at the Southern California (SoCal) Tracon, jumped from 33 in FY09 to 189 in FY10, an increase of 473 percent. Two other Tracons, at Central Florida and Houston, showed operational errors increasing by 380 percent (from 5 to 24) and 30 percent (from 11 to 44) respectively, while errors at the Miami ARTCC increased by 100 percent (from 15 to 30). Six other locations, at three Tracons, two ARTCCs and one control tower, reported increases in individual errors between 43 percent and 70 percent.

The FAA defines an operational error as an action of an air traffic controller that results in less than the required minimum separation between two or more aircraft, or between an aircraft and obstacles or an aircraft landing or departing on a runway closed to aircraft. Losses of separation due to pilot actions are called pilot deviations, but these were not included in the IG’s report.

While operational errors appear to have increased overall, the FAA’s error classification process contains some inconsistencies. On at least one occasion, controllers were blamed for separation errors that the FAA later decided were caused by its own approved procedures. At the SoCal Tracon in 2010, for example, the FAA issued a waiver to permit landings at reduced separations. But 147 landings later, the agency’s Air Traffic Safety Oversight Service revoked the waiver, reclassified the landings and added 147 operational errors to SoCal’s tab, bumping its total up by 23 percent. SoCal’s “score” was not corrected downward when the current GAO Audit Report was published.

Conversely, in 2011, Charlotte-Douglas was carrying 157 runway-incursion events on its tally. In this instance, the FAA’s local assessment that these were justified was overturned and the events were reclassified as “non-events” following a re-interpretation of the definition of a runway incursion by senior FAA officials, who determined that safety was not compromised. The 157 incursions were then removed.

There are approximately 7,000 aircraft occupying U.S. airspace at any given time. Consequently, as the IG’s report points out, losses of standard separation (when aircraft do not maintain the minimum distance apart) are a significant safety concern.

When a loss of separation occurs, it can often be unclear whether it was caused by a controller or a pilot error, or a challenging FAA procedure or even, on a number of occasions, by the aircraft following a Tcas evasive maneuver that avoided one encounter only to create a second one on its escape path. An operational error can also be assessed against a controller who fails to correct an inadequate voice response from a pilot under visual separation procedures. Unexpected go-arounds can also cause high-risk loss-of-separation events, as can aircraft arriving at the same altitude on parallel runways. So while many actual or potential loss-of-separation events reported by controllers can be clearly identified as to their cause, approximately 50 percent of their reports are classified as “unknown.”

Safety Improvement Efforts

A 50-percent success rate for an ATC safety system really isn’t good enough, and the FAA has investigated various approaches to raise that level.

For many years, the agency has used automated reporting systems at ARTCCs to spot errors, and these are still in use. But around 2010, two new concepts were introduced. First, and now in nationwide operation, the automated traffic analysis and review program (Tarp) can detect and sound an alert about losses of separation at ATC facilities, including towers and Tracons. However, the FAA has yet to publish Tarp results, although it was the agency’s early intent to examine the risks involved in separation losses detected and publicly identify corrective actions. The second concept was the Air Traffic Safety Action Program (Atsap), a voluntary, non-punitive reporting program to encourage FAA ATC employees to report safety events and concerns, with the intent of capturing all events that might lead to a breakdown in safety, provided those errors were not the result of gross negligence or illegal activity. But it was deliberately not intended to be an amnesty program. Atsap is similar to the FAA/air carrier Aviation Safety Action Program (ASAP), with similar goals.

Unfortunately, while commendable in principle, Atsap appears to have run aground on difficulties in interpretation of the program’s intent beyond its basic purpose of recording losses in separation. After de-identification of the individual submitting the report, Atsap reports and all other related reports of the event went to a three-person event review committee (ERC), composed of an FAA ATO, an FAA safety oversight person and a representative of the controllers’ union, the National Air Traffic Controllers Association.

The road to Atsap gradually became one paved with good intentions, as a result of what the IG describes as “significant challenges in identifying and addressing safety risks,” along with poor data analysis, inadequate briefings to facility managers and the frequent rejection of post-event skill enhancement training (SET). On one occasion, the ERC rejected further training for a developmental controller who was responsible for the serious loss of separation between a general aviation airplane and a Boeing 737 because there was “a lack of performance history.” The controller had been certified for his first control position just eight days earlier, hardly time to accumulate such a history. There had also been cases where facility supervisors had edited original reports. For these and several other reasons, the FAA subsequently decided to gradually phase out analysis of Atsap reports at the local facility, and replace it with a new risk analysis process (Rap).

Atsap will continue, but its reports will now be assessed by three-person Rap panels of two controllers and one pilot, and the three FAA ATO service areas in the U.S. will each host one panel, instead of the individual ad hoc ATSAP review committees previously set up at any of the 300 FAA control facilities where an Atsap report originated. Rap’s loss-of-separation standards are also simpler and based on Eurocontrol criteria, where loss of separation occurs whenever aircraft become closer than 66 percent of the approved separation (for example, less than two miles when assigned to three-mile separation).

The FAA is now putting the Rap infrastructure together at the service areas, but concerns have already been expressed about the high numbers of separation losses that the three Rap centers will be required to handle. Similarly, the service areas will also process Tarp data; FAA staff anticipate there will be 600 to 900 of those will need to be reviewed daily. The IG also questions whether the local knowledge, procedures and expertise resident at the 300 current FAA facilities can possibly be transferred to Rap personnel.