Robert Baron

        When I was at Milan Italy's Linate Airport in the winter of last year I had a real bad feeling about what I saw (or didn't see). I was flying a Learjet 31A, giving a Swiss businessman some training in his new aircraft. Our flight had departed Geneva, Switzerland around mid-morning. We did some airwork, and then shot the ILS 36R approach into Milan's single runway airport.  If you have ever flown in European airspace in the winter, you have found a whole new appreciation for IFR procedures, ATC clearances, and holding (yes, holding!). With the reported weather at Linate Airport right at minimums, it was just another typical morning in the area. Low dense fog was obscuring visibilities to ½ mile. At times it was less and at times it was more. We lucked out.... we were treated to ½ mile visibility on our approach!
        We had spent a few hours on the ground in Milan. When we got back to the airport to prepare for our short trip to Cannes, France, I started to get a bad feeling about surface movements in low visibility at Linate Airport. The general aviation-parking ramp has two routes in and out (please see exhibit A). There is a north route and a south route. When exiting the ramp, the normal and safest way to taxi is via the north route (this precludes having to cross the active runway). The south route, which can also be used to taxi to the active runway, involves crossing the runway at midpoint to get to the taxiway on the opposite side. Due to construction at the time, the only route available to get to runway 36R was the south route. We were instructed to taxi via R6, and hold short of runway 36R. At the time, the visibility was about 200 feet. We could barely see two taxi lights ahead. When we arrived at the runway 36R hold short line, I had made a mental comment to myself that this airport was ripe for a major runway incursion. Even on our taxi-out, there were factors in place that could have led to a serious ground incident.

Some of those factors included:

• Closed north ramp due to construction.
• Low visibility.
• Language problems.
• A "jog" in the taxi to cross 36R. Normally there are perpendicular taxiways in addition to the high-speed turn-offs. In this case they are angled. This creates more time crossing the active runway as well as confusion. During low visibility, this became quite a handful!
• No surface ground radar.
• Limited visibility of surface movements from the tower.
• Unfamiliarity of the airport.

        In an analysis of this accident, we can clearly see broken "links in the chain." Causal factors, including chilling similarities to my visit at Linate, included:

• The Business jet pilot using the R6 taxi route (south) for undetermined reasons.
• Low visibility (approx 700 feet).
• No surface ground radar (which, combined with low visibility, includes a general rule that all aircraft are prohibited from crossing the runway).
• Limited visibility of surface movements from the tower.

        I used a major runway incursion as an example from another country because of its significance and relevancy. But what is going on here in our own country? Are we safe? Could this or has this happened in the United States? Where have we been and where are we going on runway incursion mitigation? What measures are being taken to make sure that a tragedy of this magnitude can never happen? Let's take a closer look at some of these questions.
        To quickly put this into perspective, let's keep in mind that the accident that caused the greatest loss of life in aviation history was a runway collision at Tenerife Airport in the Canary Islands on March 27, 1977, involving two 747's. There were 583 people killed. The FAA defines a runway incursion as "Any occurrence at an airport involving an aircraft, vehicle, person, or object on the ground that creates a collision hazard or results in loss of separation with an aircraft taking off, intending to take off, landing, or intending to land."
        During a recent four-year period, total reported runway incursions increased 54% from 186 to 287. Detailed investigations of these incidents have identified three major areas contributing to runway incursions¹:

•  COMMUNICATIONS
• AIRPORT KNOWLEDGE
• COCKPIT PROCEDURES FOR MAINTAINING ORIENTATION

        Pilot/controller communication is paramount to airport surface operations. All instructions must be fully understood, particularly during high workload or when the frequency is busy. It is mandatory to read back runway "hold short" instructions verbatim. For effective communications, clear and concise is the name of the game.
        Airport knowledge is very important. If you frequent a particular airport, you probably know your way around pretty well. However, flying into an unfamiliar airport can pose many challenges. Having an airport diagram and asking ATC for "progressive taxi" can be a big help at an unfamiliar airport! I can say for a fact that taxiing around a large, unfamiliar airport at night (eg; Kennedy) can be the most complex part of our entire flight!
        Cockpit procedures and/or Standard Operating Procedures during taxi are also very important. The "sterile cockpit" rule is in effect during all taxi operations. There is no place for non-essential chatter while maintaining vigilance and running checklists during the taxi. Familiarity with light gun signals is essential should you lose radio contact with ground control. As a general rule, one pilot must always have his head outside to scan for other traffic and to prevent incursions. The other pilot may be performing checklists, talking on the radio, and doing last minute paperwork.

        How come we don't hear too much about runway incursions? Quite frankly, if it doesn't end as an accident with loss of life the media is generally not interested. Therefore, there are more incursions taking place than the general public knows about. For example, less than a year ago an American Airlines jet nearly collided with a cargo plane on a runway at Dallas/Fort Worth Airport. American Flight 2393, carrying 60 people en route to Chicago Midway Airport, had to lift off before reaching the proper takeoff speed because a cargo plane was in its path. The American flight crew estimated that they missed the other craft by 10-20 feet. The American jet was traveling more than 100 miles per hour when it passed over the other plane. According to the investigation, controllers had cleared the cargo plane to cross the runway, but after doing so, the pilots made a wrong turn back onto the runway². Was this in the news? Most likely not. Had the aircraft collided you bet it would have been front-page headlines!
        Runway incursions are such a high priority that the National Transportation Safety Board (NTSB), every year since 1990, has named runway incursions as one of the nation's top transportation safety issues, including it on its "Most Wanted" list of safety improvements. The NTSB believes that runway incursions are one of the most significant hazards in aviation today! Keep in mind that the NTSB can only make recommendations to the FAA and the FAA can accept or reject those recommendations. The NTSB has no regulatory or enforcement power.
        In the early 1990's, the number of runway incursions was declining. Beginning in 1994, however, that trend reversed, and runway incursions have since increased each year. Let's take a look at some numbers:

        The FAA records three types of runway incursions: Operational Errors; Pilot Deviations; and Vehicle/Pedestrian Deviations. All three of these categories are based on human error and a loss of appropriate separation between aircraft and/or a vehicle. An Operational Error is when an air traffic controller inappropriately clears an aircraft or vehicle into a situation that results in a collision hazard. A Pilot Deviation is when a pilot moves an aircraft into a position, without air traffic control approval, that leads to a loss of separation. Vehicle/Pedestrian Deviation is one where a vehicle or individual enters a runway without air traffic control approval that leads to a collision hazard.

FACT: Between the years 1994 to 2001, Pilot Deviation was the main cause of runway incursions in every year except 1994. The FAA has further broken down the data to show that general aviation pilots were most likely to be involved in a runway incursion. In 2000, general aviation pilots committed 76 percent of the pilot deviations³.
 
 

1. Los Angeles (33)
2. St. Louis (30)
3. Orange County (27)
4. North Las Vegas (26)
5. Long Beach (25)
6. Dallas/Fort Worth (23)
7. San Francisco (21)
8. San Diego/Montgomery Field (20)
9. Fort Lauderdale Executive (20)
10. Phoenix (18)

 There are a number of initiatives that the FAA and the NTSB are undertaking to make airport surface operations safer. Some are technical and some are simply education/awareness.

• Promoting aviation community participation in runway safety activities and solutions;
• Appointing nine regional runway safety program managers;
• Providing training, education, and awareness for pilots, controllers, and vehicle operators;
• Publishing an advisory circular for airport surface operations;
• Increasing the visibility of runway hold line markings;
• Reviewing pilot-controller phraseology;
• Providing foreign air carrier pilot training, education and awareness;
• Requiring all pilot checks, certifications, and flight reviews to incorporate performance evaluations of ground operations and test for knowledge; and
• Increasing runway incursion action team site visits from 25 in 2000 to a planned 130 in 2001 (2002 data not available).

• Airport Surface Detection Equipment - Model 3 (ASDE-3): This radar helps air traffic controllers manage the orderly movement of aircraft and ground vehicles on the airport surface, especially during low or no visibility conditions, such as rain, fog and night operations. The ASDE-3 display shows aircraft and vehicles as they operate on the airport ground. However, the radar does not tag aircraft -- in other words, each blip on the screen does not have an attached information tag that identifies the aircraft, nor does it contain any conflict prediction or alerting logic. It is strictly a surveillance system that effectively supplements the controller's vision. The FAA has commissioned the ASDE-3 radar at 33 of 34 high activity airports. (Ronald Reagan Washington National has yet to commission its ASDE-3, due to problems in getting the radar positioned properly.)
• Airport Movement Area Safety System (AMASS): AMASS builds on the ASDE-3 radar information by adding conflict detection and warning logic that visually and aurally warns air traffic controllers that a runway incursion is about to, or has, occurred. The system works by processing surveillance data from the ASDE-3, the airport surveillance radar, and the terminal automation system. It then determines conflicts based on the position, velocity and acceleration of airborne aircraft, as well as ground-based aircraft and vehicles.
• Airport Surface Detection Equipment - Model X (ASDE-X): The next generation of the ASDE-3 is known as the ASDE-X. The FAA awarded the ASDE-X contract to the Sensis Corporation in November 2000. An operational readiness demonstration is scheduled for September 2002. Unlike the ASDE-3/AMASS combination, which receives data from a single source (surface movement radar), the ASDE-X will receive and combine data from three sources: (1) surface movement radar; (2) multiple fixed transmitters and receivers situated around the airport property that will send and receive signals from aircraft transponders (known as transponder multilateration); and (3) automatic dependent surveillance broadcast (ADS-B), which uses the Global Positioning System to allow each aircraft to continuously broadcast its position.
• Runway Status Lights (RWSL): RWSL is a system of lights automatically-controlled through the use of surface radar data. These lights are designed to improve situational awareness of the runways' status by informing pilots and ground vehicle operators when a runway is unsafe to enter/cross or to begin take-off. When surveillance data from ASDE-3 and other airport radar indicate that an aircraft with a trajectory aligned with a runway is landing or taking off, or otherwise approaching an intersection with a taxiway, the red lights at that intersection are automatically illuminated.
• In-Cockpit Moving Map Displays: In-cockpit moving map displays are a promising new technology to improve pilots' situational awareness on the airport surface. Currently, pilots use paper maps to navigate the airport surface, and can become disoriented, leading to runway incursions. In fact, loss of situational awareness is thought to be the most common cause of pilot deviations, which are themselves the most common cause of runway incursions. With an electronic moving map display, the pilot can see exactly where he or she is on the airport surface at all times. The electronic moving map depicts the cleared taxi route, as well as real-time information about the aircraft's own position, other airport traffic, and hold short positions. Each runway and taxiway is identified by name on the moving map.
• Anti-Blocking Radios: Blocked radio transmissions adversely affect controller-pilot communications and thus pose a serious risk for surface incidents. Blocked, or "stepped-on," radio transmissions occur when one pilot attempts to transmit on a frequency that is already in use, either by another pilot, or air traffic control. When this happens, no one can hear either of the transmissions. Usually neither of the two parties attempting to transmit simultaneously knows that their transmission was not heard, nor do they know that they missed hearing someone else's transmission. Third parties in the area hear a distinctive squeal, so they are aware that blocked transmissions have occurred, but they do not know the content of those transmissions. There are air traffic control procedures designed to mitigate the effects of blocked transmissions; however, as with all procedures, they are not failsafe. A blocked radio transmission was cited by the investigating countries as a contributing factor to the 1977 runway collision of a PanAm and a KLM aircraft at Tenerife. In this accident, a KLM flight mistakenly began a take-off before the PanAm flight had left the runway, causing a collision that resulted in the greatest loss of life in aviation history. Just prior to this accident, two transmissions took place at the same time. The "stand by for take off... I will call you" from the tower to the KLM flight coincided with PanAm's warning message "we are still taxiing down the runway," which meant that neither transmission - either one of which should have stopped KLM in its tracks -- was received with clarity.

• Require, at all airports with scheduled passenger service, a ground movement safety system that will prevent runway incursions; the system should provide a direct warning capability to flight crews. In addition, demonstrate through computer simulations or other means that the system will, in fact, prevent incursions. (A-00-66)
• Amend 14 Code of Federal regulations (CFR) Section 91.129 (i) to require that all runway crossings be authorized only by specific air traffic control clearance, and ensure that U.S. pilots, U.S. personnel assigned to move aircraft, and pilots operating under 14 CFR Part 129 receive adequate notification of the change. (A-00-67)
• Amend Federal Aviation Administration Order 7110.65, "Air Traffic Control," to require that, when aircraft need to cross multiple runways, air traffic controllers issue an explicit crossing instruction for each runway after the previous runway has been crossed. (A-00-68)
• Amend Federal Aviation Administration Order 7110.65, "Air Traffic Control," paragraph 3-9-4, "Takeoff Position Hold," to discontinue the practice of allowing departing aircraft to hold on active runways at nighttime or at any time when ceiling and visibility conditions preclude arriving aircraft from seeing traffic on the runway in time to initiate a safe go-around maneuver. (A-00-69)
• Adopt the landing clearance procedure recommended by International Civil Aviation Organization Document 4444-RAC/501, "Procedures for Air Navigation Services-Rules of the Air and Air Traffic Services," Part V, "Aerodrome Control Service," paragraph 15.2. (A-00-70)
• Amend Federal Aviation Administration Order 7110.65, "Air Traffic Control," to require the use of standard International Civil Aviation Organization phraseology (excluding conditional phraseology) for airport surface operations, and periodically emphasize to controllers the need to use this phraseology and to speak at reasonable rates when communicating with all flight crews, especially those whose primary language is not English. (A-00-71)

        In conclusion, we can be optimistic in that the most recently released data on runway incursions (last part of 2001) has indicated a decline for the first time in many years. This is encouraging! But we have a lot of work ahead of us. As is typically the case, FAA is moving at a painfully slow rate to implement all the new technology that has been previously discussed. The equipment is long overdue and is way over budget (typical bureaucracy).  We can only hope that a catastrophe such as Milan or Tenerife can be averted until the technology and education is in place.
        In the meantime, we always need to be extra vigilant in airport surface operations. Know your airport marking and signs. Read back all "hold short" instructions. If in doubt, ask for progressive taxi instructions. We know we can never eliminate runway incursions. But with a concerted effort, we can continue the trend downward and make airport surface operations as safe as possible.
 
 

1.  Federal Aviation Administration Website (2002). Runway Incursions-A Growing Problem at Controlled Airports. Washington, DC.

2.  U.S. House of Representatives Website (2001). Subcommittee on Aviation: Hearing on Runway Incursions, Focusing on the Technology to Prevent Collisions. Washington, DC.

3.  Federal Aviation Administration Website (2002). Runway Safety. Washington, DC.