Runway Incursion Update

Air Line Pilot, May 2001, p. 30
By Capt. Tom Duke (Ret.)

"When all seems to be going well, you obviously don’t know what is going on."—Murphy’s Law

At 0040 PST, American Flight 1991, an MD-80, autolanded at Seattle/Tacoma International Airport (SEA) in low visibility on Runway 16R. The tower controller, using his state-of-the-art ASDE-3 radar, noted that the airplane was on the runway and slowing down and cleared the flight crew to "hold short of one six left...." The first officer auto-responded, "cleared to cross...."

Simultaneously, loudspeaker chatter from a towing operation on the ramp drowned out the tower controller and supervisor and distracted them, and they missed the incorrect readback.

While the tower controller was issuing the clearance, the captain was busy silencing the autopilot disconnect warning alarm and heard only the first officer’s readback to cross.

The pilots of TWA Flight 24, also an MD-80, had been holding in position, were now cleared for takeoff on 16L, and did not note the erroneous readback because they were busy powering up and starting to roll.

The tower controller turned his attention toward helping to straighten out the towing operation. The tower’s ground radar had no AMASS conflict alarm system (not yet certified at any airport), and no one concerned detected the impending near-collision.

The American crew did not see the TWA airplane coming at them, but passengers did see the landing lights. At the last second, the lightweight TWA airplane climbed over the tail of the American airplane. The noise was loud and clear on the American CVR. Vertical separation between the two MD-80s was estimated to be 38 to 100 feet.

Will Murphy live to be right again? With only three airplanes moving on the airport, two of them almost collided. Two professional airline flight crews and one tower team totally lost situational awareness for less than a minute. If existing recommended reforms had been implemented when the print on the reports was drying years ago, this near-disaster might have been avoided completely.

If the last sentence of Federal Aviation Regulation Part 91.129(i) had been deleted, the rule would have required a specific clearance to cross any runway and, in the absence of a clearance, to hold short.

If the American flight crew had received clearance to cross near the runway crossing point, as recommended by pilots in the MITRE Report ("Preventing Runway Incursions," Part 2, August 1997), chances are the flight crew would not have been distracted or busy and would have read back the clearance correctly.

If the tower controller and supervisor had not been tempted to turn their attention elsewhere, the near-collision would not have occurred.

If newer airport traffic displays and a warning system using ASDE-X trilateration radar technology, or ADS-B satellite and datalink radio technology, had been in place, warning alarms would have lit up and sounded. Situational awareness in both the cockpit and the tower would have been much improved if military-style head-up displays (HUDs) had been adapted to airline cockpits and towers and had been approved and installed. Similar technology is available with in-cockpit moving-map displays, which also significantly increase situational awareness.

Nevertheless, the current reality is that the hurry-up rush affects operations almost all day and night now at busy airports. Controllers follow the "expedite" procedures even when they are not necessary. The tower has no real priority duty to get involved in aircraft towing and movement operations outside the airport movement area. The pilots of the departing airplane could easily have waited a few seconds until the ASDE-3 showed their traffic was clear. The alternative was to keep at least one set of tower eyeballs on the radar as a safety and redundancy procedural measure.

Current operations do not have sufficient safety barriers to break a simple, everyday chain of events. They are not designed to tolerate errors.

Ironically, a few days later, another incursion occurred as a group of airport personnel at Los Angeles International Airport (LAX) was being acknowledged for activities that reduced the annual number of runway incursions at LAX. An airline flight crew had been cleared to hold short but belatedly stopped past the hold line. The tower controller then let two more airplanes land with the transgressing airplane sitting in the safety zone. The book says, "Send them around"—another shot across the bow from the laws of Murphy.

Database analysis

Let’s look at the FAA’s runway incursion and surface incident data for 2000 and see what really is going on. The FAA database lists 429 incursion reports and approximately 950 surface incidents.

The Runway Safety Program Office provided the 248 deidentified reports in which at least one aircraft being operated under FAR Part 121 was involved in an incursion or surface incident. As requested, no airlines, airports, or flight crews were named. The FAA has about 1,400 reports for all U.S. aviation operations in its database for 2000. The remaining 1,150 or so involved mainly general aviation and air taxi aircraft. These are not official, final, or totally accurate figures, but the 248 narrative briefs show that the data provide a good picture.

After the data were scrubbed for those reports in which an airliner had a conflict with another aircraft, a vehicle, or a pedestrian (real incursions), 171 were found to involve at least one FAR Part 121 aircraft. From that, we have a good picture of airline incursion reports and problems for 2000.

When scrubbing a little harder, 127 FAR Part 121 flight crews were classified as cited for pilot deviations. Of those, 50 were for such incidents as pushing back to a taxiway without clearance or crossing a runway without clearance with no other aircraft on final or the runway. This leaves FAR Part 121 flight crews with 77 pilot-deviation runway incursion reports, or 18 percent of the reported national 429 total
runway incursions in 2000. That is 6.4 per month for the U.S. air transportation system.

However, to look at the data another way, most incursions involve at least two aircraft at risk. One is involved in the cause, and the others are affected by it and usually suffer consequences. The data include 5 aircraft being towed or taxied by maintenance and 23 involved in tower operational errors, 103 aircraft operating under FAR Part 121 were put at risk as causal aircraft, and 153 were affected as a consequence. Those numbers would indicate that about five airliners per week are involved in a runway incursion.

During the first 4 months of 1998, the frequency of events was about once every other day (see "Runway Incursions Affect an Airline Pilot about Every Other Day," February 1999). Though airline pilots make up only a small part of the overall causes, the risk of being involved in a runway incursion has increased about 43 percent in the last 2 years, according to the FAA database.

Deviations and consequences

By far the greatest transgression in FAR Part 121 pilot deviations and consequences to Part 121 flight crews is crossing or entering runways without clearance from the tower (see Figure 1). The second is similar, crossing the runway’s hold-short line. Forty percent of the deviations involved aircraft taking off, aborting, or landing with conflicting other aircraft on the runway or past the taxiway hold line. At least 15 came within 500 feet of a collision. Six directly overflew another aircraft, as happened at SEA.

The flight crews of about two-thirds (94) of the consequence aircraft were inconvenienced by go-arounds, aborts, or delayed takeoffs. Based on limited mini-narrative information, at least 44 incursion events can be said to have happened with ineffective intervention by the crew or the tower controller because it was too late—a landing or takeoff occurred without collision. As happened at SEA, the current ATC system has insufficient barriers to prevent runway incursions. We need more "saves." Better still would be to need fewer saves.

FAA prevention efforts

Many of these deviations and consequences could be prevented and fixed by quickly implementing recommendations contained in the FAA’s National Blueprint for Runway Safety, published in October 2000.

Widening hold-short lines and using reflective paint on them is improving conspicuity. Also, the FAA is circulating an advisory circular (AC) for comment on how to improve flightcrew procedures to prevent many incursions.

Negotiations are also under way to allow pilots and controllers to report near incursions themselves, with limited immunity via the NASA Aviation Safety Reporting System, in which NASA will provide the interview process and analyze data for prevention efforts. These fixes involve human factors and simple technology. Another round of regional workshops on runway incursions is being conducted this spring. The regional workshops will continue to drive changes to the National Blueprint for Runway Safety. An update is planned for the fall of 2001.

Under the FAA’s Safer Skies agenda, the Commercial Aviation Safety Team (CAST) has chartered several joint groups from industry and government to recommend strategies to reduce the number of runway incursions and to improve airport safety.

Under the CAST process, the Runway Incursion Joint Safety Analysis Team (JSAT) studied all relevant runway incursion accident and incident data, established the common root causes, and assembled a prioritized list of "blue sky" interventions to reduce the risk of runway incursions.

The JSAT published its results and analysis in August 2000. ALPA Director of Engineering and Air Safety John O’Brien co-chaired the committee along with FAA Runway Safety Program Director Sue O’Brien (no relation).

In August 2000, the JSAT report was turned over to the Runway Incursion Joint Safety Implementation Team (JSIT), whose tasks are to build a consensus and to "launch real world changes during the third quarter of this year" (see "Making Airports Safer," March). ALPA’s O’Brien is tri-chair of the JSIT, along with FAA Director for Runway Safety John Mayrhofer and Dennis Roberts, representing the Aircraft Owners and Pilots Association. ALPA staff engineer Charlie Bergman, Capt. Mack Moore (United), the director of ALPA’s Airport Design and Operations Group, and Capt. Marty Coddington (Express Airlines I, Ret.) ably assist in the process.

The JSIT meets monthly to promote the best ways to reduce future runway incursions. At this point, the JSIT has released no clues about its priorities, timelines, and final report; but the group is covering seven main project areas:

Some of the major improvements they are working on can be found in the FAA’s National Blueprint for Runway Safety (which can be found at

The following discussion is based on the Blueprint’s somewhat related but different seven main thrusts:

These topics and many more will likely receive priority attention soon. Timelines are being set. Some popular, newly available technology, like moving map displays, HUDs, datalink readout taxi instructions, and the cargo fleet’s use of ADS-B may have speeded up implementation of some of the recommendations. Some general aviation aircraft in Alaska are already being vectored or flying approaches with this non-radar satellite-based ATC system. Changing procedures to deal with runway crossing clearances is gaining support.

Other effective measures, like antiblocking radio technology, have been available since the early 1980s but have not yet been perceived as urgently needed. This is due, in part, because blocked transmissions are vastly under-reported, and many occur without any proof. IFALPA and the world’s pilot community stand behind the requirement ("Pilot Report," November/December 1999, page 42).

One aircraft radio manufacturer offers a $200 retrofit, installed, for its radios. Yet no U.S. airline will voluntarily install the antiblocking system on its own. Implementing this recommendation will require long-overdue rulemaking or another Tenerife (see "Remembering Tenerife," August 2000). The FAA actually killed the recommendation after it was made at the 1995 Safety Summit.

Reality check

Meanwhile, the situation is not improving, according to press reports. However, after the Runway Safety Summit in June 2000, the number of FAR Part 121 runway incursion reports was markedly reduced—129 actual incursions (21 per month) occurred before July, and 62 (10 per month) occurred during the rest of the year. Murphy wished this news had made the papers.

To the FAA’s credit, the agency made a concerted campaign to report every incursion after the Summit. No consequences occurred in 53 reported surface incidents involving FAR Part 121 airplanes. The reports reveal 19 runway entries or crossing incidents, 8 cases of push or power back to taxiways without clearances, 8 taxiway entries without clearances, 6 runway hold point crossings, 5 takeoffs without clearance, and 3 landings on the wrong runway. Strict enforcement was being used as an educational tool at many locations. How is success measured? By increasing enforcement, of course. Or is there another marker?

Close calls

Before the June summit, the year 2000 database showed 15 close calls in which aircraft moving rapidly came within 500 feet of colliding. The database shows none came that close the rest of the year.

Here is a short summary of the close-call events in 2000. Most happened without much fanfare. It is time to really know what went on and fix the "why."

Eight of these incidents were controller errors. Four errors were assigned to FAR Part 121 pilots, two to general aviation pilots, and one to a Pepsi truck driver. Of great significance, seven of the incidents involved a total loss of situational awareness. Flight crews saved or helped save the day in seven of the cases, and ATC only two without help. Seven incidents involved runway crossings. Ten required extreme flying skills while flying over other aircraft either on the runway, shortly after takeoff, during a low altitude go-around, or during flare before landing.

Fixing the "why"

Fixing the "why" of these close calls and all the other runway incursions and surface incidents described in this article is still in the future. FAR Part 121 flight crews are being charged with fewer than 20 percent of the incursions, and the number of FAR Part 121 incursions was markedly reduced in the last half of 2000. But, for the year, an average of five FAR Part 121 airplanes were still put at risk each week, and situational awareness is lost too easily in many cases. We need more "saves."

That problem needs priority help. With the current FAA system, the events are being chronicled; but they are not examined for human factors, analyzed individually without incrimination, and added to the reinforcement needed to get the recommended help. ALPA is working to change the process by which the FAA collects and analyzes data.

Our best promise of moving forward with reducing the risk of runway incursions, however, lies in the data-driven, consensus-based CAST process. ALPA pilots and staff members are thoroughly involved with the FAA and other aviation industry/government partners in the CAST process to identify, prioritize, and implement the most powerful interventions for preventing runway incursions.

Now that you know what "really is going on," Murphy recommends letting your leaders know you are ready now for any and all improvements. Until then, be aware of the situation.

Just heard of another incident in Florida—one airplane landed over another airplane on the runway—how do you suppose that happened? As Yogi Berra once said, "It ain’t over."

Capt. Tom Duke is a charter member of the Association of Independent Airmen and has logged more than 11,400 hours in military and Part 121 four-engine transports. The former Director of Safety of the U.S. Air Force Reserve, he has been a researcher for the NTSB. His most recent article was "A Long-Standing, Successful Aviation Safety Reporting System," January.