Although the media and Congress continue to wring their collective hands over the rising number of reported runway incursions, the FAA is claiming that the severity of these incursions has remained relatively low and stable over the past four years.
The question remains, however, is if that means the glass is half empty or half full. Of the 1,359 runway incursions recorded at towered airports from 1997 to 2000, 259 required either “extreme action” to narrowly avoid a collision or posed a “significant potential” for a collision. That equates to more than one “high risk” incursion event per week.
Less than a week after the FAA released its runway safety report, Congress held a hearing on the status of the agency’s technological solutions for preventing runway incursions, and several lawmakers indicated they were less than impressed with the progress.
Department of Transportation inspector general Kenneth Mead told the House aviation subcommittee that the FAA has not done enough to provide technologies to airports with continued runway incursion problems and the agency’s runway safety program director “has little authority” to ensure that initiatives are completed.
“We are concerned that close calls have not decreased,” Mead said. “It is important to recognize that over the past four years, 161, or 63 percent, of the close calls involved at least one commercial aircraft, where the potential loss of life is much greater.”
Lurking in the background of any discussion of runway accidents is the specter of the 1977 runway collision at Tenerife Airport in the Canary Islands, in which 583 people were killed, a fact referenced by Rep. John Mica (R-Fla.), chairman of the aviation subcommittee. He pointed out that in this past decade, the FAA has published four plans designed to reduce the number of runway incursions, yet the number of runway incursions has risen steadily from 186 in 1993 to 431 last year. There have been more than 165 incursions to date this year, which he said indicates that the number of incursions is continuing to climb.
Mica further expressed displeasure with the progress of the Airport Movement Area Safety System (AMASS), which coupled with the Airport Surface Detection Equipment-Model 3 (ASDE-3), is the only technology the FAA has commissioned to date to help alleviate runway incursions. He said the version of AMASS that is currently being commissioned is “a shadow of its former self,” as well as being more than five years late and more than $90 million over the original budget estimate.
The FAA’s efforts to rein-in runway incursions also has been hampered by the turnover in the position of director of runway safety, with six changes over the past five years. William Davis, the latest to hold the post, has been on the job for about three months.
Under its new system of categorizing runway incursions from A through D, the intrusions range from near collisions to accidents to incidental events. Factored in are five interdependent operational variables–available reaction time; evasive or corrective action; environmental conditions; speed of aircraft and/or vehicle; and proximity of aircraft and/or vehicle.
According to the FAA’s office of runway safety, those five operational dimensions formed the basis for developing runway incursion categories that “capture the spectrum of severity.” In other words, the runway incursion categories define the relative margin of safety for a given runway situation.
Using the five operational dimensions to evaluate an occurance, each runway incursion is assigned to a category that best represented its relative severity, but an incursion did not have to match all five dimensions in the category. The categories increase in severity from D to A, after which the incursion results in a runway collision.
Under the FAA definitions:
• Category D–Little or no chance of collision, but the incident meets the definition of a runway incursion.
• Category C–Separation decreases, but there is ample time and distance to avoid a potential collision.
• Category B–Separation decreases and there is a significant potential for collision.
• Category A–Separation decreases and participants take extreme action to narrowly avoid a collision.
Categories A and B represent major runway incursions where there is a high risk of a collision based on the operational dimensions, while C and D represent minor runway incursions where there was little or no risk of collision.
During the four years covered by the study, there were three runway collisions that the FAA included in Category A for purposes of its analysis. One was an operational error involving a privately owned twin-engine aircraft and an airport maintenance vehicle in 1997 at New York La Guardia Airport (LGA); the second was an operational error involving two single-engine aircraft last year at Sarasota/Bradenton (Fla.) International Airport (SRQ); and the third was a vehicle/pedestrian deviation involving an airport truck and a commercial passenger jet last year at Fort Lauderdale/Hollywood (Fla.) International Airport (FLL).
The FAA attributes runway incursion occurrences to operational errors (OE), where an action by a controller results in less than the required minimum separation; to pilot deviations (PD), where a pilot violates any FAR; or to vehicle/pedestrian deviations (VPD), where pedestrians, vehicles or other objects interfere with aircraft operations without authorization from ATC.
While there was a marked increase in the number of reported runway incursions at towered airports last year–up to 431 from 321 in 1999–the good news is that 96 percent were minor in severity (categories C and D). In fact, over the four years of the study, 81 percent contained little or no risk of collision.
Thirty-seven percent of all major runway incursions (A and B) and 28 percent of all minor runway incursions (C and D) occurred at the 32 busiest of the nation’s 450 towered airports. However, Davis said there was no strong correlation between the total number of operations and the total rates of runway incursions over the four-year period studied.
“That leads us to believe that airport designs are sufficiently unique that they have a bearing on incursions,” he said. “We know what happened, but we don’t yet know why.”
He said the incursion rates seem to be exacerbated at airports with intersecting runways or where aircraft have to taxi across parallel runways to reach other points on the airport. The airports with the highest incursion numbers are, in descending order, Los Angeles International (LAX), Lambert-St. Louis International (STL), John Wayne Airport-Orange County (SNA) and Long Beach/ Daugherty (Calif.) Field (LGB).
The FAA said the increase in reported runway incursions last year was primarily attributed to pilot deviations, although most were in the relatively minor C and D categories. And, although general aviation accounted for 60 percent of the runway incursions, that was in proportion to its 58 percent of aircraft operations in the National Airspace System. Commercial aircraft, which comprise 38 percent of NAS operations, had 38 percent of the incursions. The military, which comprise 4 percent of the operations, accounted for 2 percent of the incursions.
Davis said that the FAA will release the report again next spring, adding another year’s worth of runway incursion statistics to the mix. Observing that C and D events need to be looked at as precursors to A and B events, he said, “Accidents don’t happen because somewhere in the [failure] chain that link was broken.” Davis plans to take the report to his colleagues at the FAA and decide how best to reduce the frequency and severity of the events, how the agency allocates assets and whether AMASS and ASDE-X are “going to the right airports.”
Although he conceded that FAA runway incursion data doesn’t consistently show the level of detail necessary to reliably determine the root causes of runway incursions, he said the data collection forms will be revamped to provide more detailed information on the human performance, procedural, technical and environmental factors that may have interacted to contribute to runway incursions.
Davis also vowed to share the data among members of the aviation community and provide a more user-friendly system for analyzing runway incursion data according to specific parameters.
DOT inspector general Mead, long a critic of the FAA’s glacial pace in reducing runway incursions, called the new classification system “long overdue.” But he admonished that runway safety initiatives are not completed on time, completed initiatives are not evaluated to determine if they are working and regional efforts are not periodically assessed to ensure that progress is being made to reduce incursions.
Further, Mead told the House panel that the runway safety director has “little authority” to ensure that employees from other parts of the FAA are fully supporting the runway safety program.
Mead charged that the FAA’s responses to recommendations to accelerate development of new technologies and to strengthen the director’s authority over the runway safety program are “ambiguous” and seem to lack milestones. “We will be requesting that the FAA Administrator reexamine these issues and provide specific milestone dates to implement our recommendations,” he said.