Statement on Measures Taken by the FAA To Prevent Runway Incursions
~ January 2003 ~
Since 1973, the National Transportation Safety Board (NTSB) has issued more than 100 recommendations regarding runway incursions and in 1991, the Board specifically recommended that the FAA develop a technology to prevent runway incursions. The FAA response was a software package known as the Airport Movement Area Safety System (AMASS) that it promised as the "high end" solution to incursions at larger airports.
In June 2001, the FAA conceded that the AMASS enhancement was six years behind schedule and in July 2002 reported the NAS [National Airspace System] “continues to experience about one Category A or B runway incursion per week at towered airports, thereby making runway incursions a continuing threat to aviation safety.”1 AMASS was initially introduced, on a trial basis, at San Francisco and Detroit airport (it has been suggested that this was a ruse to manipulate the program’s progress before the House Aviation Subcommittee in June 20012) and was formally implemented in May 2001. For completeness, in July 2002 the FAA confirmed that AMASS was operational in 50 percent of planned locations3.
AMASS & ASDE-3
AMASS is a hardware and software enhancement for the Airport Surface Detection Equipment-Model 3 (ASDE-3) radar system that provides safety warnings and alerts of potential runway collisions. ASDE-3 is a primary radar system designed to provide tower controllers with surveillance information – a video display – of all aircraft and other vehicle operations on an airport’s runways and taxiways. However, while ASDE-3 provides controllers with a video display to assist them in preventing potential runway collisions, controllers are not able to watch the display at all times hence the AMASS system that provides both aural and visual warnings to alert controllers to potential runway collisions. At least that is the theory. Further, ASDE-3 does not identify aircraft.
A view from the AMASS maintenance display unit at the San Francisco International Airport. This Graphic reproduced courtesy of the Volpe Centre4
In March 2000, Jim Hall, then Chairman of the NTSB, was highly critical of the real effectiveness of the AMASS enhancement during testimony he gave during a House Appropriations Transportation subcommittee hearing. He produced a computer simulation of an April 1, 1999, incident at Chicago’s O’Hare airport that showed the AMASS equipment would have given controllers just six seconds' warning. These concerns were repeated at a June 13, 2000, NTSB public meeting titled “Safety Recommendation to the Federal Aviation Administration to Prevent Runway Incursions”5:
The FAA originally developed AMASS to prevent runway incursions; however, because the FAA was unable to develop an acceptable predictive warning system, AMASS' focus was changed to prevent runway collisions. Further, the current system does not appear to be able to provide sufficient warning time to prevent even some runway collisions. Providing warnings only to air traffic controllers unnecessarily increases the time to alert flight crews of a potential runway incursion or collision, as a significant amount of time is required for the controller to detect the warning, identify the nature of the problem, and determine the necessary action before attempting to establish radio contact with the flight crew. [IASA NOTE: and always bearing in mind that there will be at least two such crews]
On the basis of its investigation of several runway incidents investigated in 1999… the Safety Board believes that an acceptable ground movement safety system should be able to provide direct warnings to flight crews and other vehicle operators of potential incursions through means such as runway edge lights and stop bars located at all runway/taxiway intersections, or by other means, such as datalink [IASA NOTE: DREADLE - an IASA developed system that is discussed later - offers such assurances]
The FAA agrees that there are limitations in their solution and have acknowledged that pilots for example are a critical component in the runway incursion prevention conundrum. Transportation Department Inspector General, Kenneth Mead, has said moving map displays, showing pilots their position and those of others near them, have the most promise of providing information to the cockpit rather than the control tower.6 Why send the alarm to the controller to relay on to the pilot instead of sending the information directly to the pilot? And there is the rub that DREADLE - for example - addresses.
The FAA is notorious for embarking on costly - ill-conceived – projects fostered by an avionics industry that is eager to sell “beyond the threshold” technology - without doing their homework, a share viewed by the General Accounting Office (GAO). In December 1998 the GAO stated:
Historically, the modernization program has experienced many problems in meeting cost, schedule, and performance goals. As a result, many of the promised benefits from using new equipment have been delayed, and the aviation community’s confidence in FAA’s ability to manage the modernization program has been weakened. Because of the complexity, cost, and problem-plagued past of FAA’s modernization program, we designated it a high-risk information technology initiative in 1995 and again in 1997.
ANTICIPATED INCREASE IN AIR TRAFFIC
Against a background of increasing air traffic the preceding makes for sombre reading. Carol Carmody, Acting NTSB Chairman, made the following comments in a speech she gave at the Air Line Pilots Association's Air Safety Forum Washington, DC August 16, 20017:
We all know about the growth of the commercial aviation industry in the last decade: eight consecutive years of air traffic growth, with significant increases in the general aviation fleet. The Federal Aviation Administration predicts by the year 2011 the number of air travelers will increase from 664.5 million to more than one billion: aircraft operations at FAA air route traffic control centers will increase from 45.7 million in 2000 to 59.4 million in 2011, growing 2.4 percent each year. The number of passengers on foreign flag air carriers traveling to or from the United States is expected to increase from approximately 137.6 million in 2000 to 239.4 million in 2011; a 5.1 percent rate of growth each year.
Along with the increase in air travelers will come an increase in transport category aircraft. According to the Boeing Aircraft Company, in 1995 there were 11,066 transport category aircraft operating around the world. That same year, there were 21 hull losses. Boeing projects that, if those trends continue by the year 2015, there will be 23,081 aircraft, about 44 hull losses -- more than double the 1995 figure.
Other technology is being touted as a possible solution such as NASA’s Runway Incursion Prevention System, or RIPS8. RIPS attacks incursions with a three-pronged approach. First, pilots can use a colour "head-down" moving map on the control panel, which graphically illustrates the runway or taxiway and warns of conflicts in either yellow (for runway traffic) or red (for runway conflict). Second, they can use a transparent head-up display, similar to that on a fighter jet, that flashes a text warning. Finally, they can hear a two-stage auditory warning. Last October, NASA tested RIPS, along with the FAA system, in a specially equipped Boeing 757 at Dallas Fort Worth International Airport. As the airliner approached to land, a van on the ground would cross a hold line and enter the runway. Out of 47 test runs, NASA's system alerted pilots 42 times, compared with 36 times for the FAA's system.9 Food for thought and certainly a technology that falls in line with NTSB criticism of a system that took the pilot out of the information loop. Other solutions include the PathProx application that has been developed by the Rannoch Corporation10 and DREADLE a technology devised by IASA (Australasia).
The DREADLE solution is simple. If each runway take-off entry or intermediate taxi-in crossing-point intersection had a holding-point treadle (weight-actuated) incursion alarm set to Tower and Ground frequencies, each incipient incursion would immediately be notified (by an attention-getting warbling tone) to pilots on both the Tower and Ground Movement Frequency (for pilots in the pattern, on ILS finals, taxiing and lined up on the runway or rolling). Any taxiing pilot who thought he’d triggered that VHF audible alarm would immediately stop/check his position. In fact, all taxiing aircraft and those about to roll would be mandated to do so (i.e., stop and check for the hazard aircraft or vehicle). An aircraft taking off in poor visibility (below decision speed) would abort.
The treadles, twin pressure-sensitive transducers a few feet apart (and similar to traffic counters seen everywhere on the highways), and associated logic circuitry and plumbing, are not that daunting a technological prospect. The installation could feature an adjacent nose wheel-activated strobe light. That would immediately pinpoint the perpetrator and also alert the offending crew, even in bad visibility. Further enhancements might include a green/amber/red light at each take-off runway entry taxiway treadle - directed at the next take-off candidate. We would suggest you visit http://www.iasa.com.au/dreadle.htm for more information.
“A chain is only as strong as its weakest link”
Sadly, in the case of aviation safety the weakest link is the FAA. On previous occasions, the FAA has been charged with a safety critical task and failed miserably. One need only look to the FAA’s record (or rather lack of record) on aviation security to realise that when dealing with the FAA theory is very different to practice.
Whilst all those engaged in aviation safety agree that the increase in air traffic, both actual and predicted, brings with it the very real prospect of incursions becoming collisions. A recurring theme in such discussions is that the pilot is an information-critical component in any system. AMASS is a controller specific decision-making tool that relies upon safety-critical information being relayed through the controller to the pilot. Further, as the NTSB simulation demonstrated the AMASS “enhancement” provides the controller with a negligible window of opportunity and as NASA has demonstrated the AMASS “success” rate was 76% compared to NASA’s 89%.
The International Aviation Safety Association (IASA) is a financially and politically independent non-profit organisation concerned in all aspects of aviation safety. Mrs. Lyn S Romano established IASA on the 4th March 1999 following the death of her husband, Raymond M Romano, when a Swissair operated MD11 crashed off the coast of Nova Scotia, Canada, on the 2nd September 1998. A total of 229 people were killed. On May 10, 2000, the President’s Executive Office declared the safety concerns associated with aging wiring in aircraft an “issue of national concern”. The President’s Executive Office praised IASA for bringing these issues to the White House’s attention. In May 2002, IASA was invited by NASA to inspect the wiring aboard the Space Shuttle Discovery during the 20-24 month maintenance mode.
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