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Issues in the Interactions of Airline Dispatchers and Flight Crews with the Traffic Management System
August, 1997

* Cognitive Systems Engineering Laboratory, The Ohio State University, ** Department of Aviation Ohio University, *** NASA Ames Research Center

In order to explore issues of concern in the interactions of airline dispatchers with flight crews and with the traffic management system, a panel was convened with 11 experts representing these different system perspectives. A set of 9 scenarios representing actual events was collected to focus the discussion.

In very general terms, the resultant discussions emphasized the need for:

•  Better mutual understanding of the viewpoints and capabilities of others within the system;
•  The need for increased and more effective communication and information exchange;
•  The potential value of collaboration shared decision making in identifying potential problems and
in developing solutions to these problems (both at a programmatic level and in terms of daily
strategic planning and the tactical handling of situations that have developed);
•  The importance of making the system less susceptible to impact of the inevitable slips and
mistakes that individuals will occasionally make;
•  The importance of understanding where there are significant capacity limitations so that, in
the short run they can be dealt with as effectively as possible, and so that in the long run these
limitations can be reduced or eliminated.

As a specific example, the first scenario discussed illustrates the potential for human error when, to reduce cognitive complexity, the overall task of selecting safe routes of flight and of operating these flights is decomposed such that each of the participants (pilots, controllers, dispatchers and traffic managers) has only partial information. In particular, within the current air traffic management system, tactical decisions are made by flight crews and controllers without always having the information necessary to develop the same big picture about weather system developments available dispatchers and traffic managers. Additionally, at times, controllers are initiating reroutes of flights which do not have sufficient fuel for that route, indicating the need for dispatchers to be included in all reroute planning where the changed route is significantly different from the filed route so as to ensure compliance with applicable FARs. Although this distribution of information and responsibilities generally affords an efficient operation, it is susceptible to occasional errors due to false assumptions about "what the other guy has already considered." In addition to providing insights into the causes of such problems, potential solutions were also outlined as part of the panel discussion, such as the use of technology to provide alerts to the relevant parties in such situations.

Later scenarios further emphasized concerns over information access, such as the need to better inform flight crews about the likelihood of encountering air traffic control programs while enroute due to developing weather, and the need to communicate the rationale behind flight plans developed by dispatch under the expanded National Route Program, making explicit situations where refiling direct is likely to be less efficient than staying on the filed NRP route because of winds. Similarly, there were clear illustrations of the need for dispatchers to access to forecasts about potential traffic bottlenecks and to have the tools to help them consider such forecasts when developing flight plans.

Still other scenarios emphasized the importance of more effectively incorporating different systems perspectives in daily decision making, so that they don't introduce unnecessary inefficiencies. This applies to the interactions of airline operations centers with the traffic management system as well as to interactions within components of the FAA traffic management organization. For example, one problem that was highlighted during the discussion had to do with a failure to adequately consider the "terminal perspective" when instituting ground delay programs:

TRACON Manager: "We are not great advocates of ground delay programs before severe weather. From the terminal perspective, we know that the enroute facilities need them. However, there are a lot of other facilities surrounding us that aren't enroute facilities, and we can move airplanes at low altitudes through the enroute structure, through the nine approach controls that butt into our area. They can get penalized in ground delay programs, and the problem really is that the programs are not surgical enough."

Additional examples and details on such concerns are provided in this report under the summaries of the discussions associated with each of the 9 scenarios.

Overview As part of the annual Airline Dispatchers Federation Safety Symposium, a panel was organized to discuss issues dealing with the interactions of Airline Operations Centers (AOCs), flight crews and traffic managers. The panelists included:

2 commercial airline pilots (2 additional pilots were invited but could not attend)

4 commercial airline dispatchers

4 traffic managers (3 from ARTCCs and one from a TRACON)

1 specialist from the Air Traffic Control Systems Command Center (ATCSCC)

To focus the discussion, a number of actual events or scenarios that had actually occurred prior to the meeting were documented for discussion by the panel. These scenarios were presented one at a time to the participants, who were then asked to discuss them from their different perspectives. Below, the scenarios and the resultant discussions are summarized.

Scenario 1 This first scenario involved a Boeing 727-200 from Dallas/Ft. Worth to Miami. As part of his job, the dispatcher responsible for this aircraft was required to provide the pilot in command information regarding any hazardous enroute weather. In this case, the dispatcher noted a line of thunderstorms that he felt potentially jeopardized the safety of the flight and issued a reroute to the aircraft, with the Captain's concurrence. During this process, the Captain was briefed on the situation. That reroute was coordinated with ATC and approved, but as the flight progressed along its refiled route of flight, the receiving Center rejected the reroute and put the airplane back on its originally filed route of flight. As a result, the aircraft became trapped south of the line of weather.

More specifically, Figure 1 shows the aircraft situation display (ASD) for this flight, showing the aircraft as it was enroute from the Tallahassee VOR to Miami. As the aircraft was going across the Florida panhandle, there was a line of thunderstorms arcing from the Tampa Bay area southeastward down to the Miami/Ft. Lauderdale area.

Figure 1. Situation Display for Scenario 1.

At that point, the dispatcher contacted the captain, briefed him on the enroute weather conditions, and recommended a reroute taking the aircraft direct Ormond Beach and then down the east coast of Florida into the Miami airport from the northeast, ahead of the weather. The Captain concurred with the reroute and contacted the appropriate Jacksonville Center frequency to coordinate the reroute. The reroute was approved. The aircraft made a turn to the east and was proceeding direct Ormond Beach on the Florida East Coast. At the point where there was a hand-off made from one controlling Center sector to the next Center, the receiving Center sector advised the Captain that, due to traffic along the east coast of Florida, they would not be able to accommodate the reroute and that the aircraft would have to return to the originally filed route of flight. The aircraft made a fairly abrupt turn back to the southwest, got offshore along the west coast of Florida and proceeded down toward the Ft. Myers area. Furthermore, the aircraft was slowed to 180 knots due to traffic, increasing fuel burn.

At that time, the line of thunderstorms was sinking to the southeast moving down toward Miami/Ft. Lauderdale/Sarasota/Ft. Myers. As the aircraft arrived in that vicinity and was preparing to turn to the east for the final to Miami to land to the east, the weather came across the airport and shut down the operation. As a result, as shown by the signature on the ASD display, the aircraft entered airborne holding and was given "expect further times from ATC" that continued into the future. Thus, the crew was faced with an indefinite situation as to when they would be released to proceed into Miami.

It was not until this point that the Captain contacted the aircraft's dispatcher and advised the dispatcher that the reroute the Captain and the dispatcher had agreed upon had been refused by an ATC sector, that the aircraft had ended up back on its original filed route of flight, and had encountered airborne holding. The dispatcher's attention had been diverted to another situation and he had not noted the ATC-mandated reroute. Thus, at that point the aircraft was holding with thunderstorms between its position and the intended destination. What complicated this scenario is that Sarasota, Ft. Myers, Ft. Lauderdale and West Palm Beach, which were all of the other usable alternate airports for this aircraft, were either unusable due to thunderstorms or were now north of the weather as well. The aircraft was basically trapped south of its intended destination and south of its usable alternates. (This aircraft was not authorized to use the Key West airport.) Consequently, the crew was faced with a situation of being very low on fuel with limited options in terms of available diversion airports. The aircraft finally broke through the line of thunderstorms as the weather passed south of Miami, and was able to land at Miami. However, they picked up significant turbulence going through the line of weather. It was not a comfortable ride for the crew or the passengers, but the aircraft finally landed having encountered severe turbulence.

It is also important to understand that the dispatcher working this particular flight on this day had about 30 other flights that he was responsible for at that time, and felt as though this situation had been resolved and had turned his attention to other situations that required his attention.

Issues Raised by Panelists | A number of important considerations were highlighted in the resultant discussion. These included issues dealing with information access, communication, training and coordination.

Situation Assessment from an ATC Perspective | To interpret this scenario, it is important to understand the motivations of the controller involved.

Traffic Manager: "It seems like everything was going smoothly until it got closer to Ormond Beach and they were advised to reroute over the west side of the state. On a daily basis, when there are thunderstorms, the approach that Miami Center takes is that they send all their Miami/Ft. Lauderdale/Palm Beach departures up the east coast, and Jacksonville Center usually goes single stream over St. Pete, coupled with miles-in-trail over ??? Lee County, and will come there. Preferably we'll take the Palm Beach and Ft. Lauderdale traffic through the center of the state because they are the first ones that get off. The Miami traffic is taken around the horn, so that they can get them from the south side.

It was stated that one sector refused to take the hand-off. According to the map, it appears that this happened very close to the boundary line between Jacksonville and Miami Centers. At that point, Miami probably requested all aircraft be rerouted over one fix, so that they could get their departures up the east coast and their arrivals down the west coast.

Thus, that is where this happened. It was the hand-off from Jacksonville Center to Miami Center."

Traffic Manager: "It is important to understand that Orlando and Miami are very busy airports. Consequently, there is a standard route, ??? Norfolk-Charleston-Ormond Beach, ??? 57, to keep the traffic density manageable. Thus, if, when the Jacksonville controller approved the reroute, he did not coordinate with the Miami controller, it is easy to see how the Miami controller might subsequently reject the reroute from his local perspective.

Specifically, if a Miami controller is looking at his traffic for Orlando, all coming over Ormond Beach and being routed down ??? J74, he's likely to want to reject the reroute because he's got to deal with a heavy volume of traffic coming in from Europe. This traffic has got priority over U.S. domestic flights because it's already in the air and is running on minimum fuel.

In this particular case, however, we have a conflict between this standard traffic management strategy and constraints due to weather."

Information Access, Communication and Coordination | Because we only have partial data on this situation, it is impossible to determine exactly what transpired. However, the probable explanation for this situation is that:

•  The receiving controller at Miami Center was unaware of the potential hazard that could result from putting the flight back on its original route because he did not have access to a display of the weather in that area. As a result, his request for the flight to return to its original route was based on his standard method for achieving a smooth traffic flow;

•   The flight crew had been informed of the potential hazard when they talked with the dispatcher, but assumed (incorrectly) that the controller was making the request based on updated information about the weather;

•   Because of this assumption, the crew accepted the controller's request without raising questions about the weather situation, and furthermore did not contact dispatch to make sure the weather had indeed cleared sufficiently to make the original route of flight safe.

As stated by one of the panel members:

Pilot: "I think a couple of issues come up. One is the big picture issue. At our airline, the dispatcher has a view of the weather that the ATC folks [controllers] do not have."

These comments seem to have several implications:

•   Given the current distribution of access to weather information, flight crews - a. need a good understanding of the limited access that controllers have regarding weather information, so that they are less likely to assume that the controller has considered that factor adequately; b. need to understand the importance of talking with dispatch to get an updated view of the weather situation and to ensure compliance with applicable FARs;

•   Given the tendency for people to unintentionally make assumptions, improved training of flight crews may be insufficient. A further protection against such errors would be to institute a procedure whereby, when reroutes are approved that are based on safety critical weather concerns, the reason for the reroute should be tagged on the flight strip. Some simple code like Wx Reroute could be used to communicate this. (Such a code might further indicate whether the request came from the airline or from a traffic manager.) This would inform the controller that there are factors outside of his or her scope that need to be considered, and that appropriate parties (dispatchers and traffic managers) need to be included in the decision making.

In the long run, this scenario further suggests the value of giving everyone access to a bigger picture, so that they have a common framework for considering and discussing alternatives. Equally important, it also suggests the potential value of developing software to monitor for "significant" reroutings of flights, so that the appropriate parties can be alerted automatically. (This could be done within both airline and FAA software.)

These conclusions were supported by a number of comments by the panel:

Pilot: "That's probably a fault of the crew to a certain extent. Quite frankly, it's just not sufficiently common knowledge out there [among pilots] that they need to contact the dispatcher and tell them what's going on because of their ability to have the big picture and help us make the smartest choice. Then we can tell the ATC guy: "Hey, if we do that, we're going to get stuck. We cannot get to our destination, so we need to think about landing somewhere short, or you need to think about giving us some leeway, and letting us go down the east coast.'"

Pilot: "This tunnel vision or narrowing of focus happens to all three parties in this very situation. The problem starts on this flight in Dallas/Ft. Worth when the pilots started out that morning. Where was their weather briefing? What was their preparation to have this big picture that I've heard seven or eight people allude to so far? Folks, it doesn't exist. I've got news for you. We get the best weather information before we start on a flight from the Weather Channel in the morning. That works great if it's my first flight of the day, but maybe I'm into my thirteenth or fourteenth hour of duty, and this is my fifth leg of the day, and my weather information from the Weather Channel at the Holiday Inn is about sixteen hours old now. Where's my big picture? ... That's where the problem starts. I would ask as my first question: "What kind of big picture did this crew start out with before they got to the panhandle of Florida?" Second question. Where is their most recent weather information enroute? We're still depending on voice, trying to get to the dispatcher with our other workload. I'll agree with the gentleman at the end of the panel all day long that the decision to not try to get back with the dispatcher was obviously a flawed one. But what if we can't get to that dispatcher in time? Maybe set up holding there if you can. Maybe try to renegotiate another clearance on the east coast of the state. I don't know. There are several solutions here. I've been in this situation several times and I've gotten as far out as Bimini ??? . On the other hand, the controller may not have time to talk to you, and they'll flat out tell you: 'I don't have time to deal with you. Turn right to heading 220, descend and maintain flight level 220 and shut up until you're spoken to!'

So when I'm in my fourteenth hour on my duty, I've got a few problems too. So we turn right, and maybe some other things are happening. We haven't called dispatcher right away. A rather weak excuse, I'll admit, but I can see how this kind of thing can happen. The solution? Better information earlier on, and the solution you raised, the key point of where to raise the flag. Alert points maybe."

Dispatcher: "I hate to say it, but I think the onus goes back to the crew. They were originally briefed on the reroute and told that they could not file their original flight plan route, and then they were rerouted back on the flight plan route that they were just told by the dispatcher that they couldn't fly. They should have called the dispatcher and said: 'Hey, I just got a reroute back to my original route. Can I get some help from you?' Then they could have had the dispatcher working through the Command Center to try and resolve the problem."

Dispatcher: "I think often times when air traffic control communicates a route to an aircraft, the Captain on that aircraft is lead to believe, or believes, that the route that they are being given has been evaluated and is perceived to be safe. I'm not sure that the flight crews are as aware as they should be that often times ATC isn't aware of the full situation. They're looking at traffic flows, reducing saturation, and not necessarily what's happening in south Florida. The controller has his sector up there and he's managing aircraft there, but he's not really looking as far ahead as the dispatcher might."

Traffic Manager: "They are trying to establish their flow. They have to realize that, when Miami Center gets their aircraft, we going to put these airplanes going southbound, because we've got the northbound push coming up. So he's not supposed to be just looking out for his particular sector. He's suppose to look out for the overall effect on the system, and how he is going to get those aircraft in a safe position, and still have operations continue north and south."

ATCSCC Specialist: "Well, as far as the Command Center perspective, a lot of times, especially in the Miami area and Jacksonville, they do such a good job on their own that we don't initiate a lot of standard reroutes. They usually handle their concerns in-house between Miami and Jacksonville. Maybe it's something that we need to get more involved in if we knew it is going to be a problem. Maybe we need to take a bigger look at this at the Command Center, and monitor it more."

Scenario 2 | The description of Scenario 2 was very straightforward: One form of cooperation between airline operations centers (AOCs) and traffic managers is the use of pathfinders to help locate routes that are opening up after a severe weather disturbance.

Issues Raised by Panelists | Three issues were discussed in the context of this scenario. The first emphasized that this was an example where there was useful cooperation between the airlines and the ATM system. The second had to do with the legality of releasing such "pathfinders". The third had to do with the need to involve dispatch in such decisions.

Cooperation Between AOCs and the Traffic Management System | One of the points made in this discussion was the value of cooperation between AOCs and the ATM system in such circumstances. Dispatchers, flight crews, traffic managers and controllers are all interested in determining when the weather has cleared sufficiently to safely open up a route.

Traffic Manager: "From the Center viewpoint, we like pathfinders. We encourage them. It's normally a route that we're looking to re-open and the pathfinder that's going out there is going into an area where we don't have any traffic anyway. So we're looking for that airplane to open that route so that we can get back to business as normal. So we encourage them. The only problem we get into is when the pathfinder goes through and says its clear, and the next three guys come and won't take the route."

Command Center Specialist: "At the Command Center, we find pathfinders by calling the dispatchers, by calling ATC reps. In addition, a lot of times the Centers will call us and say: 'Hey, I've got a pathfinder.' We'll talk directly with the pilot, that usually works out really well. The guy takes off, he'll zig zag or do what he needs to do, and we'll find out if the route is open. For those who don't know what a pathfinder is, it's somebody that we send out just to see if a route is open, if we can open it again, or what the situation is.

We get a lot of calls from the dispatchers or ATC reps who say: 'Hey, this looks pretty good over here. How about if we go over this way? I've got a couple of guys that want to try it.' So we go: 'Okay, we'll take care of it' and we call the particular Center or the particular terminal."

Issues Regarding Legality | mOne of the issues that arose concerned the circumstances under which it was legal for a dispatcher to release such a flight.

Dispatcher: "Pathfinders, a term dear to my heart! A pathfinder is an airplane that is sent out to try and open a route. It's my understanding that when the Command Center or one of the controllers agrees to take a pathfinder, they've taken it under the assumption that there is the possibility that this airplane may not be able to penetrate, and they have built room into the airspace in order to accommodate in case the airplane has to deviate. ... The fact is that this airplane may have to do some deviating to go around it. But as far as the selection of pathfinders, I think you got to talk to the crew."

Dispatcher: "I've offered some of my airplanes as pathfinders in the past, but one of the questions that no one seems to be able to answer is what is the regulatory protection for pathfinders? In other words, we are not suppose to dispatch our aircraft through severe weather, right? So, from a regulatory standpoint, what protection do these crews have when they accept the role of pathfinder? What if there is an incident? What if there is some kind of deal where they hit turbulence? What protection do I as a dispatcher have when allowing the crew of my aircraft to be a pathfinder if something goes south?"

Traffic Manager: "FAR 121.663 says that you cannot release a flight, or a Captain cannot accept a reroute without conferring with the dispatcher. You as the dispatcher are not going to put a flight on a route that you feel is unflyable. So therefore, you as a dispatcher would never recommend a flight as a pathfinder unless you were confident, based on what the radar pictures are showing you, and everything that is available to you, that that crew could not safely execute that route."

Traffic Manager: "From my own perspective, although there is a possibility that the pathfinder won't make it, the fact of the matter is that we don't put airplanes through severe weather. So when we release pathfinders, we believe there is a very good chance of success. We expect the airplane to get through. We expect to find out what the route is like. We expect to find what the band width is of the system at that time. How many can we take? How wide is he deviating, and where is he going to go to? But he's going to get to where he is going in most cases. We're not going to put him out in a scenario like the last one [Scenario 1]. We're not going to put him up the backside of that thunderstorm, and hope he's going to pick his way through."

Dispatcher: "Apparently, if we need a pathfinder, there has got to be some element of doubt that this is a safe way to go or we wouldn't be calling it a pathfinder. Otherwise we'd just start clearing airplanes that way. I personally will not give clearance for any of my pilots to act as a pathfinder. As many sophisticated tools as my company has, if somebody needs a pathfinder, they better find somebody else to dispatch it, because I don't have the tools to take the chance."

Dispatcher: "My experience with pathfinders has been that the request for a pathfinder originates with the dispatcher because he thinks ATC has got everything stopped up when it shouldn't be. In other words, he's evaluated whether he feels his airplane can go through this area with no turbulence and no weather encounter, but ATC is not letting us go there. So it's the dispatcher and the carrier that suggests: 'Hey, we think we can get through there safely, with that dispatcher's signature on there certifying that yes it can.' We clear it with the Captain."

Traffic Manager: "Going back to what your original question was, I think the answer is, it's your decision as the dispatcher. If you do not feel the route is a legal route that you can release him on, then he doesn't go. It's up to you. It's your decision. You have to make that decision along with the Captain."

Dispatcher Involvement | There was further concern over cases where such pathfinders proceed without the involvement of dispatch in the decision.

Dispatcher: "There are instances where dispatch is cut out of the loop on this, where air traffic will offer the route to the pilot in command. It's too fast. ATC will say to a pilot: 'You want to go through this area in bad weather and be a pathfinder for us?' And away it goes! This happens especially when there is airborne holding where flights are trying to get through."

Traffic Manager: "Under FAR 121.663, they cannot accept a reroute without conferring with the dispatcher."

Pilot: "But 8410 says each operator will specify how much of a deviation is allowable from the planned dispatch release before the dispatcher needs to be involved. Your limit could be 100 miles or 4,000 feet or a change affecting the ETA by 15 minutes either side."

Pilot: "That's what they pay you for. You make that decision. If you think you need to speak to dispatch and get his advice on that, then you do so. But I mean, you've got your radar, you're talking to ATC, and there is a certain amount of judgment that has to be involved. If I had to stop every time my flight path changed ... I'd be out of gas a long time before I reached my destination! I'm trying to keep the dispatcher as much in the loop as I can, but realizing that person is not just concentrating on me, he's working thirty other flights. I have to be allowed a certain amount of judgment."

Scenario 2 - Summary | Although the discussion ended with a certain amount of disagreement among the panelists as to whether and when such pathfinders should be allowed, several points were made. First, it appeared that there was agreement that such flights should be released only when there is a clear belief that the route to be explored was likely to be open. Second, it is important to ensure that contingencies are available just in case the data suggesting the availability of a route are incorrect. Third, in cases involving significant reroutes, dispatch involvement is required from a legal perspective. In cases involving smaller flight amendments, the pilots emphasized that judgment regarding whether to involve dispatch is necessary (keeping in mind that dispatch has access to information that may be unavailable to the flight crew and controllers).

Scenario 3 | The third scenario presented a situation where collaboration between the airline and the Command Center proved beneficial, and emphasized the potential value of information exchange between AOCs and the Command Center. In this scenario, there was a line of weather tracking just south of Chicago from Kansas City, pretty much up to Detroit.

Command Center Specialist: "To deal with this weather situation, the south departures out of Chicago were going west, then down to Kansas City and around backside of the line and then back on course to the Florida airports. That routing had been in place for probably an hour or so, and the weather started breaking up so that it really wasn't any longer a solid line, but the Command Center staff hadn't had time to notice that because things were pretty hectic down at the severe weather unit, dealing with a lot of Centers and a lot of different events.

At that point, a dispatcher from one of the airlines called the Command Center and said: 'Hey, we're getting some guys through here and there. How about going back to the normal route?' As a result the Command Center took a look at the situation, talked to the affected Center, and found out that it was in fact breaking up a little bit.

The conclusion was that it was now possible to allow flights back on the normal route, but not at the normal capacity. The approach we took was to call up a couple of airlines and say: 'Hey, listen. You can continue to go down the Kansas City way with no miles-in-trail and no delays. Alternatively, you can go ahead and go back to the old route, but we will have to restrict you to 30 miles-in-trail so that the affected Center can deal with any necessary deviations.' This worked out well. If the dispatcher hadn't called, we might have kept that other routing for an hour and the airlines would have continued sucking up gas. Thus, this is a story that really worked out well for everyone."

Information Exchange | One of the things this scenario emphasizes is that the airlines and the Command Center sometimes have access to different sources of information. Furthermore, the Command Center has staffing limitations that may divert its attention away from a particular situation as long as it is under control from a traffic management perspective. (As the Command Center Specialist commented: 'We had the reroutes that we needed in this area and things were running smoothly, so now we were focusing our attention on other parts of the country.')

However, because communication between AOCs and the Command Center is increasingly becoming a standard practice, it was possible for the airlines to call attention to the opportunity to go back to the standard, more fuel efficient routing in this case. Without this collaborative exchange of information, the Command Center might have unnecessarily kept the weather routing for an additional hour.

Providing Options | This scenario also illustrates one approach to traffic management: Informing the airlines about the available options and letting them make the decision as to which option to select. Thus, in this case, the Command Center indicated that there were continuing restrictions, but that because the weather situation had improved, additional options were now available. This gave the airlines an opportunity to make decisions about which flights to file along which routes.

The importance of this approach was further emphasized by comments made by the Command Center Specialist:

"I want to encourage everybody to call us on different options. Just because you see an advisory, okay, that's the decision we made with the information that we had. If there are different ideas out there, or different things that you think that we could do or if you see things differently, or you get a better weather forecast, give the specialist a call and we'll take a look at it. There are a lot of different ways to deal with a reroute or a lot of different programs that we can try. If you guys would rather take the miles-in-trail and sit on the ground for a half hour versus going 300 miles out of your way, let us know.

There are different things that we can do, but we can't think of them all on our own because there is a lot going on and we focus in on a lot of different areas. When things get busy, we really don't have time. So give us a call."

This attitude was further emphasized by the TMO from Chicago Center: "I think we've made great progress in the last few years, mainly in the area of SWAPs. ... My unit in Chicago works very well with United Airlines, its ATC reps and dispatchers, as far as coordinating SWAP routes. ... We talk to them so that everybody is planning ahead so it's not a surprise when an airplane gets to the runway. I think we've made some pretty good progress on that in the last few years."

Scenario 4 | Command Center Specialist: "This was a situation where there was a thunderstorm. It wasn't going to hit Chicago. The weather was, however, going to affect the south fixes. Consequently, Chicago was a two fix operation, or was going to be shortly.

Checking with the severe weather people, the Command Center Specialist involved discussed the possibility of putting an enroute program in effect, but not necessarily one at the airport. Only the south departures and the two south arrival fixes were being impacted so they were still getting through, but it was only a matter of time. To deal with the situation, four of the major users into O'Hare were called up. The options were discussed for about half an hour. The Command Center Specialist felt that a program was necessary based on an estimate that it would be an average twenty-three minute delay if a program was put into place then. (Looking back, we should have put this program in effect two hours earlier to take care of the already airborne inventory.) The maximum was about a forty minute delay. During the discussion, the airlines brought in their weather people and all four of them basically said: 'We'd rather go with airborne holding.' We responded with: 'Okay, we'll do that, but just keep in mind if we have to go into a national ground stop, the only way we're going to be able to get out of it is probably with a program.' One of the dispatchers called back about ten minutes later and said: 'Hey, I can support you on a program, if you really think it's necessary.' So I think he was unsure at the time. We ended up putting out a program with a forty-five minute average delay, with a sixty/sixty-five minute maximum delay.

I guess the bottom line is that there are certain ways you can handle the system. Unless the weather is actually impacting the airport, the airlines tend to want us to stay away from programs, as they think programs are bad things. They really are not. In this case for example, we were still leaving two fixes to an airport that normally has four fixes, and even though the weather isn't going to impact the airport, it's impacting the area, and it's impacting the departures. It's impacting the arrivals. The airplanes still have to get there, whether it's from the East coast or the West Coast. So there is still an impact on the airport."

Traffic Manager: "I'll just add a couple of comments. I remember that shift pretty well. The two south fixes did end up closed off. We wound up taking everything off the West Coast up over our northwest cornerpost, coming in over Mason City/Ft. Dodge, up in that area. Everything from the East Coast was coming into the northeast fix. We had asked for programs too, but we were turned down and told: 'Well, the users don't want it since the airport is not going to be impacted by the weather.' But there were many diversions that night also. There were sixty plus diversions. Many of them ended up down in Indianapolis. I'll tell you who really had to work that night was Kansas City/Indianapolis/Cleveland, because they had all our airplanes. The users got what they wanted, but did we do the right thing? I don't know."

Moderator: "Do any of the airlines have thoughts on whether they did the right thing?"

Dispatcher: "I have to give it to you. You were right that day! (laughter) But we could sit here and talk for the next eight hours about ground delay programs as opposed to ground stops in thunderstorm situations. The majority of the time, a ground delay program on a station because of thunderstorms only delays my airplanes into the thunderstorms. I would prefer, speaking for my carrier, to see a ground stop. But in this case, the south fixes were impacted and to me, when I talk about O'Hare, I don't talk about the airport, I talk about all four fixes around the airport as well. So a ground delay program in that case was warranted. We were wrong, and you heard it here first!"

Traffic Manager: "A ground delay program really isn't that bad. If you see the effects of the alternatives it's sometimes pretty ugly. You've got miles-in-trail that sometimes get up to forty, to fifty, to sixty miles-in-trail. You've got delays that can reach forty-five to sixty minutes. You've got ground stops that can last up to sixty minutes, and then it's hell trying to get out of them, especially with O'Hare. You basically have to come out with a whole new program. So you've really got to consider the possible consequences. With the program, even if you're looking at an average twenty-five minute or thirty minute delay, you can still substitute flights. To me, it's a lot more organized. You're slowing down the system and it's not as chaotic for the Centers. It's not an exact science and it probably never will be, but it's getting a lot better with the increased collaboration with the airlines."

Dispatcher: "I just wanted to back up your statement that ground delays aren't all that bad. Speaking from a dispatch standpoint, after you've been doing it for a few years, you come into work in the afternoon, you look at the maps, you look at the weather, there is no program in place and you know it's going to hit the fan. You have to start to building in extra holding fuel on your aircraft because there is no program in place. Especially in the northeast corridor."

Traffic Manager: "We often request the ground delay programs for enroute weather even when the airport is not going to be impacted. We know the program is not going to be that successful, because when the storms move in, everybody's going to move. Everybody is going to deviate. We're probably going to ground stop anyway. What it allows us to do, though, is to let us get a little measure of comfort out there. Instead of running with 100% traffic, we're running with 85%. Those extra few airplanes not in that scenario make it much more manageable."

Moderator: "It's clearly useful for everyone to have a better understanding of the other guy's perspective. In addition, however, there is the issue of who and how should decisions be made when there is disagreement."

Command Center Specialist: "We're in the middle because the airlines don't want a program and the Centers do want a program. If we do put in a program, however, the end result is it's a lot smoother for the Centers. You usually don't get the miles-in-trail, and the delays are often brought down to fifteen minutes instead of forty-five minutes. I'm not saying that in every case a ground delay is warranted, but when it is, it helps out."

TRACON Manager: "We are not great advocates of ground delay programs before severe weather. From the terminal perspective, we know that the enroute facilities need them. However, there are a lot of other facilities surrounding us that aren't enroute facilities, and we can move airplanes at low altitudes through the enroute structure, through the nine approach controls that butt into our area. They can get penalized in ground delay programs, and the problem really is that the programs are not surgical enough."

Pilot: "It sure seems to me that the tail is wagging the dog on this issue. What's the system there for? It's to allow the operators to take passengers back and forth across our system. I understand that you all have constraints, but if the airlines choose to put extra fuel on board because they want to hold because they've got to run an on-time operation and they'll pay the fuel penalty, I think they ought to be getting some discretion or some latitude. Obviously when the ATC System simply cannot handle the load, then there has to be some tradeoff, but I think too many times the tradeoff tends to slide towards ATC. Another point is it would be nice from a pilot's point of view to know when we can expect these things. I get a little blurb on my flight plan that says 'fuel for enroute delays,' but it would be nice to know that ground stops, or ground holds, or whatever, are anticipated, so we might think a little bit further ahead."

Audience Question: "I work for a regional carrier out of O'Hare. Every time a flow control program is implemented, after the delay we see other airlines getting clearances, while we're still under the understanding that we're still involved in a flow control program. We see aircraft that are departing from the majors, but we're not.

Dispatcher: "If there is a ground delay program on at O'Hare, the majors are probably running slot substitution programs, which means they have canceled flights in order to get those other flights out on time. You have the opportunity to do the same thing if you want to do it, and it should be easier with new procedures being developed for the Collaborative Decision Making program. That will change a lot of this stuff."

Audience Question: "At one time, I had something to do with ATC coordination. Is ATC still under the restriction that you can't plan for holding?"

Command Center Specialist: "There was an order that used to be out, but it expired and has been replaced by the managed arrival reservoir (MAR) program. Even though the order is canceled, however, it's still a philosophy at the Command Center. What we do now, though, is we front load the program so that if Chicago or Atlanta or whoever we are running the program for that day say they can handle a 38 rate, what we'll do is put in 44 or 46 rate at the beginning of the program. In addition, before putting in a program, we look at the numbers and if there is enough capacity there at the beginning of a rush to be handled by MAR without putting a program in, we'll do that."

Scenario 4 | Summary A number of important issues were highlighted in the discussion of this scenario. First, the importance of keeping everyone apprised of possible developments was noted. In this regard, it was suggested that the airlines may need to provide pilots with more information about the reasons for adding extra fuel, so that they can better monitor how the situation is actually developing and plan appropriately.

Second, the discussion raised issues about the decision-making process when bad weather develops. On the one hand, it is clear that if there is a potential for safety concerns to develop, then there is unanimous support for the traffic managers involved to take appropriate actions. On the other hand, sometimes there is disagreement between the airlines and traffic managers about likely weather developments and about the appropriate control actions to deal with these developments. When these disagreements only deal with concerns over efficiency rather than safety, a challenging question arises: On what basis should the final decision be made?

In this scenario, all of the airlines disagreed with the traffic managers during their discussion. Since only concerns over efficiency were involved, the traffic managers elected to go with the airlines' judgment (which after the fact the airlines concluded was an incorrect judgment). The reasoning was that, in such a case, it was the airlines who would pay the price for the resultant inefficiencies if their judgment was wrong, so it seemed reasonable to let them recommend how to deal with the weather situation.

Such judgments are not always clear cut, however. Some solutions that result in inefficiencies may also, because they result in more complex traffic patterns or congestion, have unanticipated impacts on safety. Hence, it was suggested that approaches that give the airlines additional but limited flexibility (such as the MAR program) may provide an appropriate compromise in many cases.

In part because of time limitations, these issues were not fully resolved in the discussion. A number of important issues merit further discussion between the airlines and traffic managers, including:

•   How can the airlines best be involved in discussions about how to handle severe weather problems? What information needs to be distributed among the discussants so that everyone has a broad enough view of the system?

•   When only concerns about efficiency are involved, who should have the final say in how to respond to a weather problem? (Interesting variations on this arises when the airlines - or the broader user community - are not in agreement among themselves, or where an individual airline's preference based on it's business concerns is in conflict with solutions that maximize overall system efficiency.)

•   Given concerns over efficiency and safety tend to interact in many situations, how do we ensure that the process leading to decisions based on efficiency has ensured adequate consideration of safety issues?

•   Do programs like MAR provide an effective approach to give the airlines the flexibility to deal with their business concerns while giving traffic managers the tools they need to ensure safety? If so, are there similar programs that could be instituted to further increase flexibility?

In addition, a very important question was raised about the impact of ground delay programs on TRACONs and other terminal facilities. It was suggested that current practices unnecessarily limit certain traffic, that they are not "surgical enough."

Scenario 5 | The fifth scenario focused on an issue that arose with the introduction of the expanded National Route Program. Specifically, this issue concerned cornerpost loading (see Figure 2).

Traffic Manager: "Okay, this is the noon arrival push to DFW. It starts hitting our boundary at about 10:30 to about 10:45. We have two arrival fixes at DFW for flights from the Southwest. One is over the northwest corner, which is Bridgeport. One is over the southwest corner. Because of upper winds, the user preferred route of flight to DFW from Southern California is often to the northwest cornerpost. The FAA preferred route out of Southern California from Los Angeles /Ontario/ Long Beach/ John Wayne/ San Diego and Phoenix is over El Paso to the southwest cornerpost. On this particular day, a number of aircraft were originally filed up over Texaco to the northwest cornerpost. When they departed Southern California, however, we moved some of them south via Albuquerque Center, and brought them in over El Paso. That was to give the two northern sectors, the arrival sector and the sector on the west side of Ft. Worth Center some relief. We also pulled an additional four aircraft, the one's that are in the little box (see Figure 2), down to Tuscola to fit in with the southern stream in order to further relieve the congestion. Additionally, the sector near the little cluster shown in the panhandle that says TXO or Texaco often has departing aircraft that file to depart in that direction going to Denver and Seattle. Quite often we'll take those aircraft and reroute them up over Ardmore and just west of Oklahoma City up over Liberal.

We're supposed to try to leave NRP flights alone. Unfortunately, all the flights that come out of Southern California are NRP and if we were going to leave those alone, we would have to pull flights from the north such as from San Francisco and cross them over the top of the flow of traffic. That's not very efficient, so we wind up moving some of the NRP flights."

Dispatcher: "What was the criteria for picking which airplanes you wanted to move?"

Traffic Manager: "Generally, when they start departing, we look at them out around the LA/Albuquerque boundary. We look for the aircraft that are going to be involved in the congestion and for the aircraft furthest south in that group. We normally move the flights that are furthest to the south."

Dispatcher: So what your saying is that you could be moving an MD80 which has, by he time it gets to Dallas, maybe 30 minutes of fuel capacity instead of the airplane right behind him which is a 767 and which may have enough fuel on board to orbit Dallas for three or four hours. Do you coordinate with the user in case there is a preference for which one to move?"

Traffic Manager: "We normally don't have enough time to coordinate with the user, because the decision has to be made in just a few minutes. LA has asked us at times to try to do it before the flight is off the ground, but that doesn't work because then we could move an aircraft that might be 20 or 30 minutes later than normal and we will have moved him unnecessarily."

Figure 2. Cornerpost Balancing Problem

Dispatcher: "This is a great argument for giving the airlines monitor alert. It's a classic case where the airlines could help you out when they know a sector is going to go red, planning for an airplane to take a little more deviation, and maybe moving that airplane for you, getting you out of this situation. Right now we don't know when it's going to happen, so we can't help you. But if you give us monitor alert, when it works, it would help us both out."

Moderator: "Do you think it's feasible to give the airlines more information so that they can help make these decisions?"

Traffic Manager: "I'm sure it would help. However, most of these decisions are made after the flights depart. So although it's a daily occurrence, I don't know which flights are going to be affected ahead of time. I need to have the leeway to say: 'These three flights here are right in the middle of it. I need to move those flights.' The 767 brought up earlier as an example may be a non-issue in such a case."

Traffic Manager: "I don't think it's feasible. I've heard a lot about how we are suppose to get all these people involved, that I should get on the phone every time we have to move a plane and talk with dispatch, and get the pilots onboard, and talk to the controller who's working these airplanes. Have we ever heard the expression: 'Too many cooks spoil the broth?' Certainly we should talk about this in forums like this, but when we get down to it, who are we going to move? We're going to move the first plane or the plane that's going to make our situation work better, and meet our obligation to provide a safe, expeditious flow of traffic. If that means breaking off NRPs at some point, yes we are going to have to. When you talk about these high capacity airports, you have a problem when the airlines all try go to the same point at the same time."

Dispatcher: "We fly a schedule. I can take some deviation on a flight if it's going to help alleviate the situation and still maintain my schedule if I know enough ahead of time, if I know before the airplane leaves Los Angeles. Then you guys don't get involved."

Traffic Manager: "I have yet to see where a airline scheduling department really takes into consideration the capacity of the air traffic system. So part of the problem is that different parts of the system are only considering part of the picture. The air traffic bottlenecks somehow need to be taken into consideration."

Dispatcher: "I'm not going to open up the can of worms of scheduling. Somebody mentioned the other night that, at one of the last classes they took at the air traffic Command Center, one of the controllers brought up the discussion about scheduling, saying: 'Why don't the airlines fly their airplanes at night? Eastern did it?' The comment back to him was: 'You don't see anybody here from Eastern do you?' We have got to fly the airplanes when the people want to fly. Otherwise we aren't going to make any money. If you get into scheduling here, it's out of our hands. We have no choice. We have to work with what the marketing department gives us to work with. To go back to what I said originally, I think the sooner we know that you've got a problem there, the better. It's much more economical if I have to reroute an airplane that's back in California's airspace then it is if I have to reroute the airplane when he gets into Texas airspace. I can do the first with a slight deviation on the route, whereas the other one is going to cost me more money. The further back I am, the sooner I know that we've got a problem, the sooner I can help you deal with your problem."

Command Center Specialist: "One of the airlines that flies into Newark, which I won't name, calls us occasionally and checks with us about NRPing over Slate Run rather than coming over Robinsville. Depending on the weather that day, depending on the traffic that day, and depending on a lot of things, it seems to help. If we're going to get a heavy flow over Robinsville and they send a majority of their airplanes over Slate Run, we can reduce the restriction over Robinsville. Or if we have some heavy weather over Slate Run, blocking Chicago and Cleveland getting to New York, it takes a lot of the workload off of us if they just take the pref over Robinsville. To deal with these problems, we could be communicating back and forth to reduce the delays and get the airplanes in."

Dispatcher: "As a dispatcher, I don't see any problem if you move a guy one fix north or one fix south when he is coming in from the last fix before a terminal area. That's not major to me unless there is some weather down there. What I do have a major problem with, though, is a flight coming out of Denver/Phoenix to New York which has been planned on a minimum fuel burn route at a specific speed to minimize the fuel flow, and which, as soon as he gets in the air, ATC orders him to fly just about to Atlanta and then come up to New York. We just cannot do this! You brief the crew. You put it on the release, and then the next thing you know, you see them out in the middle of nowhere, knowing he does not have the fuel to do this! For traffic reasons. It's similar to the Jacksonville example we looked at earlier. The decision to put that guy out on the west coast was made for traffic reasons without any regard for weather, and it's not right! Somebody needs to be looking at this big picture! I though the TMUs were doing it, but..."

Scenario 5 | Summary This scenario, dealing with the cornerpost balancing problems that have arisen with the expanded NRP, serves to emphasize several points:

•  Through the expanded NRP, the airlines are expressing their preferences for flying certain routes. In some cases, such as the example illustrated in this scenario, the system has some significant capacity limitation that is interfering with the use of such user preferred flight plans. Thus, an important question in such cases is: Can capacity somehow be increased to reduce or eliminate these bottlenecks?

•   In the short run, in cases where such bottlenecks do exist, the airlines may want to be more conservative in filing such routes (if their goal is to reduce flight times or fuel consumption), filing them only when the estimated savings (based on estimates ignoring air traffic considerations) are sufficiently high;

•   If sufficiently accurate data can be provided to the airlines regarding predicted traffic bottlenecks and the likely response of the traffic management system to these bottlenecks, flight planning systems could take these data into account to adjust routes. Similarly, if better forecasts could be developed to allow an airline to predict which flights will be impacted by a bottleneck, the airline could make adjustments pre-flight (when it is most cost effective to do so). A good example of this is flights from Washington, D.C. to Cincinnati, which are filed under the expanded NRP but are frequently held to lower than planned altitudes because of crossing traffic. In such a case, the airline must start carrying extra fuel on all flights from DC to Cincinnati because it doesn't know which ones will be held at lower altitudes.

Scenario 6 | Another issue that has arisen with the expanded NRP has to do with overflights crossing departure and arrival lanes at airports.

Traffic Manager: "The problem for Chicago arose when the expanded NRP first came in. Chicago Center is obviously set up to feed O'Hare. Our arrival sectors sit on the four corner posts, and our ??? sectors sit on the straight south, straight east, straight west, straight north. We are set up to feed the airport. A lot of our sectors, specifically on the south side (sectors that are just north of J80 prior to getting into either Indianapolis or Kansas City Center and sectors that are south of J60 ??? 64) were designed for specific traffic flows, for departures only. These sectors didn't work any enroute traffic, because that's not where the jet airways were. Well, along came the NRP and now the airplanes are not on the airways anymore. They are criss-crossing through sectors where we didn't used to have traffic. These are small sectors. They have flight times of six or seven minutes. They were designed for transition traffic. They move a large volume of airplanes in a very quick, efficient fashion. Early on when this started we had some big problems. We had to make some adjustments and ended up opening super highs above all of them, but it took a while to get them open and to get the controllers to buy into it and support the program.

Compounding this was the direct routes problem. Controllers often resolve traffic conflicts by giving an airplane direct. That's just the easiest way to do it. If somebody is too close to somebody, he's overtaken somebody, instead of slowing them or S turning them, he picks out some VOR, two states away, and says: 'How about direct here?' The pilot says: 'Sure, that's a shortcut.' Away he goes. Sometimes they leave NRP in the remarks section of the flight plan and sometimes they don't. An increase in directs with the NRP was causing other traffic flow problems.

All in all, in the two years since we started the expanded NRP, we struggled early on, but we adapted and managed, and now we really have very little problem with NRP flights or direct routes. It really works pretty well.

We have one scenario left that's still a problem, that's the Iowa City/Waterloo route. What happens is that, with the NRP, they identify a point where the NRP stops and the flight must join a published preferred IFR route or a STAR that feeds the arrival route into Minneapolis. That's what this point is. The 200 mile point which is a common reference point is Iowa City, and it feeds the transition for the ??? arrival, which feeds Minneapolis from the south. The preferred IFR arrival route since time began, for everything from New Orleans to Jacksonville or even further north, always came up J89 over Badger and fed over the top of O'Hare so it didn't intermingle with departures going east or departures going west. Everybody knows the best way to cross a busy airport is to go over the top. But now, with the Iowa City/Waterloo route being filed under the NRP, the airlines are saving twenty, twenty-five, twenty-six, twenty-seven miles by being able to go direct to Iowa City. So it's a significant savings in fuel and in time for many airplanes, especially when they fly their winter schedule. Our problem is that it goes through right when O'Hare is flushing their west departures. We've got three strings of departure traffic going out, three independent areas, which used to be pretty sterile. That's how we moved so many airplanes so fast, by segregating the airspace. The problem now is that we are going to have to learn to work it with those NRP flights in there. We may have to go to a miles-in-trail restriction. We've already experimented with splitting a sector. Maybe if we ever get to some reduced vertical separation standards, maybe that will help. It's a big nightmare for the controller when he's crossing three streams of departure traffic, and not only that, the flight is descending. He's transitional. That's the problem we face.

When Northwest Airlines doubles their flights starting later this fall, coming out of Portland going to Minneapolis, they'll all want to go over Iowa City/Waterloo. Guess what? That crosses right through the three main departure routes of O'Hare. That's going to be a big problem for us."

Dispatcher: "I've got a question for you. What if we go SID to STAR and knock off the 200 mile egress/ingress restriction?"

Traffic Manager: "Are you going to let me redesign the STAR?"

Dispatcher: "I'll work with you on it!"

Traffic Manager: "It's also worth noting that we've had similar problems with other overflights and sources of traffic congestion that we have been able to deal with, such as east-west overflights over O'Hare. We dealt with it by talking with the other Centers early in the day to see what was coming. This made the traffic management units more dynamic, reaching out much further, talking to each other. Everyday Cleveland Center is now not only working with us, but they are working with Minneapolis and Denver and looking at the Newark problem. If the dispatchers could become a part of this, and plan a little better based on information about traffic flows, we wouldn't have to react quite as much. But by looking ahead more and communicating, we have learned to react when the traffic flows are there."

Scenario 6 | Summary In this brief discussion four points were made. First, that in some Centers there is a serious problem with overflights filed under the expanded NRP interfering with and thus delaying departures from major airports. Second, to deal with this capacity constraint at present, either departures have to be delayed, NRP flights have to be rerouted, or miles-in-trail restrictions have to be imposed. Third, potential solutions to reduce problems like the Iowa City/Waterloo example include redesigning sectors, developing procedures and technologies to reduce required minimum vertical separation standards or redesigning egress/ingress restrictions. Finally, in other cases (like the east-west flights over O'Hare) improved communication and early coordination among Centers and with dispatchers may be sufficient to greatly reduce problems.

Scenario 7 | Another scenario that has become important with the institution of the expanded NRP has been the refiling of NRP flights to fly direct. In Scenario 6, it was indicated that the air traffic system has learned to cope with this in terms of air traffic control. It remains a problem, however, from an airline perspective.

Dispatcher: "I know of one case where the direct route was so bad compared to the originally filed NRP route that the flight wound up an hour and a half late because they had to land short and refuel. And there are lots of examples where the original route was filed to take advantage of the jetstream, so it wasn't filed direct and where, once enroute, the pilot accepted a direct route. This resulted in lost time and fuel. In these cases, the pilot perspective seems to be: 'The hell with dispatch. I'm in the best position to know about the weather. I'm here. I'm flying this bird and I know what's going on. We'll take a direct.'"

Dispatcher: "There are a lot of internal issues at the airlines concerned with the National Route Program. There is a real big communication breakdown. If we're not all singing off the same sheet of music, then nobody really knows the rules and everybody is rolling their own, and that doesn't work!"

Pilot: "I want to come to the pilots' defense on this. ... If I'm the pilot in command of an airplane and I've got a flight and I see NRP, it doesn't tell me anything. If I see route "B", it doesn't tell me that that is the most economical route. All the airlines have to do is to let the pilot know that the flight plan he has been given is the minimum cost route and he won't take directs. But when he doesn't know why the route was selected and he's offered a direct, he thinks he's cutting corners and knocking mileage off, when he may actually be losing the tailwind or going into a headwind."

Dispatcher: "You're right. We don't tell the pilot why he's flight planned where he is. It would go a long way for us to start doing that, to let the pilot know when direct is not the best."

Scenario 8 |
Moderator: "The next scenario was an: 'I can't believe this really happened scenario.' It touches on an extreme situation, but nevertheless, it did actually happen. We'd like to ask the group to look at what happened and evaluate why, so that maybe how we could prevent it in the future.

We're going to look at a Boston to New York/LaGuardia 727 flight. The flight was planned by the dispatcher on a weather avoidance route, southeast of a line of thunderstorms. The route was coordinated with the Command Center before the aircraft left the gate. As soon as the aircraft became airborne, the crew contacted the dispatcher and advised him that they had been given an ATC reroute. What you see (see Figure 3) is that reroute put the aircraft behind a line of thunderstorms, with its intended destination south of that weather. After the flight had continued for nearly an hour, it actually had to double back almost to its origin, and then flew the route that the dispatcher had filed in the first place.

More specifically, this is the valid composite weather radar display at 2110 Z (see Figure 3). This is about 5:10 p.m. The aircraft was enroute from Boston through New York/LaGuardia. There is an ATC preferred route in this particular market that would take the aircraft westbound out of Boston, over Barnes, almost to the Hudson River. Then it would turn to the south, down into LaGuardia. The dispatcher had coordinated a route with the Command Center over Sandy Point, Rhode Island/Hampton, Long Island, and then into LaGuardia from the east. That route had been approved before the aircraft left the gate. The dispatcher gave the Captain a very complete and thorough briefing on the enroute weather conditions, with specific reference to the location of the thunderstorms and made mention of the fact that, based on what the dispatcher was seeing on the ASD, it appeared as though ATC was attempting to take aircraft northwest bound out of Boston, over Manchester/Cambridge/Albany, and then into New York from the north.

The dispatcher told the Captain: 'If that route is offered to you, refuse it, and advise me thereof.' [Based on the tape of the interaction between the dispatcher and the pilot]: the Captain has just told the dispatcher that shortly after take-off he was given an ATC reroute that took him from Boston direct Manchester/New Hampshire/Cambridge/Albany, Victor 157, down to LaGuardia. This aircraft became airborne at 2050 Z, about twenty minutes before this photograph (Figure 3) was taken. The dispatcher upon hearing this stated to the Captain on the radio that he did not concur with that routing, and would not approve the aircraft to fly on that route, and he requested that the Captain advise ATC of that fact. He further stated that if the flight was not allowed to fly the filed route of flight, it should go on airborne hold until it could get this situation resolved. The crew talked to ATC, and then came back to the dispatcher. What the Captain told the dispatcher was that ATC told him that if he went Boston direct Hartford, he would not be able to pick his way through the weather enroute to LaGuardia. That communication took place at 2055 Z. Again, this is at 2110 Z, so that communication took place about 15 minutes before this picture was saved. But the dispatcher, upon hearing that said: 'Negative. There is no weather between your present position and Hartford. The weather is northwest of Hartford, northwest of New York, and you should have no trouble at the very least going direct Hartford, radar vector direct LaGuardia. So if we can't fly the filed route of flight over Sandy Point, Hampton, let's at least try to go direct Hartford, and if you can't get resolution with the controller your working with, try to get a supervisor on the frequency and ask the supervisor to intervene for you.

The Captain said: 'We've got the supervisor on the radio, and he told us that the only route that ATC will allow us to fly is Boston direct Manchester/Cambridge/Albany victor 157 LaGuardia. We have the choice of orbiting Boston until this is resolved, or accepting the reroute as mandated by ATC. Now as you can see on here, there are a few breaks in this line of weather, and as you'll see (Figure 4), there were aircraft getting through that particular area of thunderstorms. So the dispatcher, given the available options, concurred with the reroute at this point, and basically advised the Captain that there was enroute weather. So when he goes direct to Albany, he will have to pick his way through the weather to get down to LaGuardia, but it appears that aircraft are getting through that particular area.

Then we go to the next picture (see Figure 4). This is the ASD display. Here's the departure airport, Boston, and destination airport, LaGuardia. Here's that same line of weather that we looked at, and here's the aircraft that we're talking about. Having departed Boston now, you can see that it's over southwestern New Hampshire, proceeding direct Albany. Victor 157 comes down in this approximate area. You can see Kingston/Valre/Hart/LaGuardia, that's Victor 157, the standard route into LaGuardia. Obviously the dispatcher now is very concerned about this situation. The aircraft is not where he wanted it to be. There is a good deal of enroute weather. He's looking at factors such as fuel. He's looking at factors such as airborne holding, and he's keeping in close touch with this aircraft.

This dispatcher had assigned duel alternates to this flight. Philly to the southwest. Bradley to the northeast. This 727 departed from Boston with 30,000 pounds of fuel. 30,000 on a 727 is about 4 hours of flying. The dispatcher obviously anticipated that this would not be a routine flight down there and fueled the aircraft accordingly. I also will say that this is all that airplane could handle with the passenger load, and that, if the dispatcher could have put more fuel on it, he probably would have.

At 2130 Zulu, the aircraft was placed in airborne holding at the Albany VOR, and given an EFC, an expect further clearance time 30 minutes later than his arrival at the fix. This little area of weather that you are seeing northwest of Valre had expanded and the aircraft was unable to penetrate the weather in this particular area. As a consequence, New York Center gave the aircraft holding with an EFC of 30 minutes from the time that he arrived there.

Finally, due to the inability of this aircraft to proceed south from the departing VOR to LaGuardia, ATC gave him a revised routing into LaGuardia, which basically put him back to the east, over Hampton/Long Island, and then into LaGuardia. As you recall from the beginning of this scenario, the filed route of flight on this aircraft was Boston/Sandy Point/Hampton/LaGuardia. Thus, ATC returned this flight to the route it was originally filed on.

I have three questions. First, how is it that a route that has been coordinated and approved with the Command Center is refused as soon as the aircraft gets airborne? Second, how is it that a swap route that has obviously been constructed by the ATC folks positions an aircraft behind a line of thunderstorms with its intended destination south of the weather? Third, what do we as dispatchers do when we are placed in a situation where we do not want to accept a route, but the only option available to us is to stop?"

Figure 3. Initial Situation for Scenario 8

Figure 4. Later Situation in Scenario 8

Traffic Manager: "I'd like to just take a couple of stabs at this one. I'd say just from the onset it was an ill advised flight in the first place. We have 57 airports in the New York Metro area and we run about 7,000 operations a day. Not a whole lot of LaGuardia flights occur south of Hartford. Everything else is north. You don't want to be down over Long Island. We work within a very rigid, structured system. We get efficiency through that. It is not a fluid, flexible system. It's able to respond rapidly to a moving line of thunderstorms. So when I say it's an ill advised flight, if you see that weather and you've dispatched before, you probably know that you don't very often go out over Long Island to get into LaGuardia."

Dispatcher: "This is a 4:30 p.m. departure from Boston to LaGuardia. The 5:30, the 6:30 and the 7:30 all flew Sandy Point/Hampton direct LaGuardia and operated on time. Furthermore, on days with this type of weather situation, that's the routing that works and that's the routing that was worked out with the Command Center before this flight departed Boston. So I don't know that I would say that this is an ill advised flight. It was a legal flight on a route that was coordinated with ATC, free of any severe weather. The flight had sufficient fuel on it, the alternates were solid and I can't frankly see where that's ill advised."

Traffic Manager: "Okay, fair enough."

Traffic Manager: "The decision to push them up north in the first place would reside outside the New York area. Boston Center would have had a reason for going up there, but I don't think that it was an intention to put an airplane behind the weather when they moved him up there. However, if you look at the tools people are using out in the field, most of this stuff is because the controller that is making those decisions has a very poor picture of what is going on. In addition, usually the dispatchers have different information than the traffic managers. The reasons that we're making decisions are never the same, and we're not making them with the same tools. For that reason there is a extreme discontinuity in what happens in our system. So when you look at why this happened, certainly it was not intentional. Not out of malice, but out of ignorance. And not out of stupidity."

Dispatcher: "I used to work that sector for my airline and, in defense of ATC, I think Boston looks as though they were trying to deliver aircraft over the fix that New York Center wants them over. They just stretched out a little bit too long. In defense of the people in Boston, New York Center and the TRACON, I've also had crews call me, either taxing in at LaGuardia or on final and say: 'Hey, we just came down whatever that Long Island fix is. You might want to tell the guys behind that ATC is doing a nice job', or on the other hand: 'They sent us up over Albany and we came right down the river and that was good.' So I'm not so sure this is really an anomaly. I don't know how this particular situation happened, but we're talking about a really compressed time here. This is not a Transcon. This is a 40 minute trip and I don't know what we can do about stuff with that time compression."

Dispatcher: "In this case it was a 40 minute trip that took 2 hours and 10 minutes."

Traffic Manager: " Your points are all valid. However, I don't have the answer to the problem. I can't explain to you in short order what happens to the air traffic system when you move a line of thunderstorms like that so close to New York or Chicago or a Dallas."

Command Center Specialist: "Just before we move on, I want to encourage everybody to call us on different options. When you see an advisory, that's the decision we made with the information that we had. If there are different ideas out there, or different things that you think that we could do or if you see things differently, or you have a better weather forecast, give the specialist a call and we'll take a look at it. There are a lot of different ways through for a reroute and a lot of different programs that we can try. If you guys would rather take the miles-in-trail and sit on the ground for a half hour versus going 300 miles out of your way, let us know. There are different things that we can do, but we can't think of them all on our own.

Traffic Manger: "As a success story, I think we've made great progress in the last few years, mainly in the area of swaps. My unit in Chicago works very well with the airline ATC reps and dispatchers as far as coordinating swap routes. They have to agree to these routes, so that everybody is planning ahead, so that it's not a surprise when an airplane gets to the runway. I think we've made some pretty good progress on that in the last few years."

Scenario 9 |
Dispatcher: "This is August 20, 1996, 1935 Z. Detroit is ground stopped. I'm sitting on an airplane in Chicago trying to go to Washington. O'Hare is on ground stop, all eastbound departures have been stopped coming out of Chicago to the East Coast. As you can see, you've got a line of thunderstorms that extend from Ft. Wayne up to Buffalo. At 2010, Cleveland Center's traffic from Washington Center is rerouted until 23 Z. At 2024, the Detroit ground stop is extended until 21 Z. 2027, Boston/New York traffic to O'Hare is rerouted. I believe the reroutes were up in through Canadian airspace if my memory serves me right. At 2056 Z, Detroit's ground stopped till 22 Z except for Aurora and Minneapolis Center. Bear in mind that traffic is still sitting on the ground in Chicago and building up. 2021 Z, O'Hare eastbound traffic is rerouted until midnight Z. 2221 Z, Detroit is rerouted until midnight Z. 2226, O'Hare is ground stopped until 23 Z, and that's only one map. I have subsequent maps for every hour after that one. I believe that one is at 21 Z when it was taken.

The weather really never got to Chicago. The weather stayed basically where it is shown (see Figure 5) through the whole afternoon. It took me 4 1/2 hours to get from O'Hare to Dallas. I had an airplane sitting on the ground that was trying to go to Grand Rapids, and they would not let him go, mainly because he was backed up so far in the line, they couldn't get him to a taxiway so they could get him out of line to get to the end of the runway so he could take off. Because now Chicago was just about virtually gridlocked. Without going through all the advisories through the rest of the day, let me just summarize by saying that Chicago finally came out of the ground stop, I believe, at ??? 2 Z. That's the scenario."

Moderator: "Does anybody from a traffic management perspective have a comment on why this problem arose?

Traffic Manager: "Do I have to? That was one very frustrating shift! I remember it very well. The traffic management coordinators even wrote into our log that night: 'Traffic management is nonexistent.' We got so far behind that coordination really broke down that night. That was part of it. We were shut off east into Cleveland. That's what stopped it for us. Cleveland would not take anything going eastbound out of Chicago. Normally when that happens, we get routes into Canada or we get routes down through Indianapolis. The Canadians weren't taking anything up north of us. A few Boston flights did go, but I think they stayed out of Canadian airspace and we got them up through the ??? sector in Cleveland. I'm not sure what the problem was that night. I heard that the Canadians had what we call "resource problems," or "staffing issues," and they wouldn't accept anything that night. As you can see, with the weather where it is, to go south down through Indianapolis was an extensive reroute which involved not only Indianapolis, but then Washington Center. I know that at one point, we coordinated routes for the East Coast airports to come down south, come through Indianapolis. The Command Center was on, Indianapolis Center was on, and Indianapolis agreed to the routes. We no more than launched, we no more than got aircraft started off O'Hare, and sectors at Indianapolis wouldn't take the hand-offs because Washington had already shut off Indianapolis with high altitude holding. So we shouldn't have even been departing. That's how far we were behind in the communications. So it's one of the things we've got problems with when weather affects a vast area. Here you've got weather that's impacting not only Chicago, but also New York and Washington, the three busiest metroplexes in the country. It didn't work well. It was a very frustrating shift that evening!"

Figure 5. Situation for Scenario 9

Command Center Specialist: "I was lucky. I was on leave at the time. I checked my book when you brought this scenario up. Any time you've got a line in that area, it's going to have a big impact. Even if it doesn't hit the airports, it cuts off a lot of your major routes, and just getting in and out of Chicago and getting to the east coast is tough. It really depends on who's working, right down to the controller, all the way up to who's working in Indy that night in the TMU unit. It's just a lot of negotiation. We deal with the Canadians, and the Canadians are very temperamental when it comes to staffing problems and the weather. If the weather is up in their airspace you might as well not even call them. They are getting better though. They are starting to call us and say: 'Hey, do we need to keep staff on overtime, does it look like it's going to be a problem?' So we are getting some help there. That's one of our major relief routes up that way, and if the Canadians aren't cooperating, you don't even get a fighting chance. When your dealing with Cleveland and Indy, if you've got airplanes in there, they expect you to move other airplanes that are normally in their airspace further south into Atlanta. Now your dealing with Atlanta and it just depends on who you are dealing with that night."

Dispatcher: "I have a question. If what you are looking at is a printout of an ASD display, all those little red dots that you see, those are airplanes. You can't tell on very well on this copy, but if you look at the map here that I have a copy of, you will also find little red dots within that thunderstorm activity. Those are airplanes are going through that area. If those airplanes can get through the area, why can't I?"

Traffic Manager: "We ran into several problems like that this year. What we found in many cases was that, especially in the New York area, the pilots that have less sophisticated airplanes have no problem flying absolutely anywhere in any kind of weather, because they can't see it. They will visually deviate. I'm not saying that taking radar out of the aircraft is the answer, but at the same time, the pilot in the more sophisticated aircraft sees the weather and says that he's not going to go through it, period. We've found that to be pretty much the case, and when your dealing with 250 or 280 departures an hour on a selected number of routes, once you throw a cog in the wheel, the whole thing falls apart. "

Dispatcher: "One other thing that I should point out. What you are looking in this picture as far as the radar is what's called "echotops." You really can't see it on that picture because the colors are not that good. But looking at the map, I'm looking at tops in that system somewhere between 30 and 35 thousand feet in isolated areas. The majority of it is down below 20,000 feet. My ops specs tell me that I can top a thunderstorm by 5,000 feet and fly right over top of it. So part of the problem is that we're not looking at the same picture. I'm looking at this and I can't see why I can't get airplanes through that area, because I'm going to fly over the top of the whole thing. The picture that the Command Center has is not necessarily the same thing, however."

Traffic Manager: "One of the things that is going on there is that the cloud tops are often not consistent. There are some out there 35,000/40,000 feet and there are some areas that are 20,000/25,000 feet. The areas that are 20,000/25,000 foot tops are where the few airplanes that are out there are located. But there is very little airspace left out there, and you can see how much traffic is in the air. The areas that are available are already being used, and that's part of the reason why you get into ground stops and you can't hardly get out of them. The other thing that we talked about is the gridlock. O'Hare turns around every hour, hour and a half, I mean it has to turn. They come in, they fill up the gates and then they have to leave. If we have departure restrictions and we're not getting out, then they don't get off the airport and that's when we start approaching gridlock. If you don't slow down the AAR, the arrival rate, pretty soon you have no room left to turn somebody off the runway. We can turn around 155 airplanes an hour. So O'Hare, even though it's a nice sunny day and is sitting there clear and dry, we may have a 60 arrival rate because of the weather out East. It's hard to understand when you see 112/125 airplanes backed up waiting for departure that you have to slow them down or they won't be able to turn off the runway because we'll have a gridlock situation."

Dispatcher: "My question is, for the future, for next summer, what can we do?"

Command Center Specialist: "There are two aspects to your question. One is communications. We employ a hotline in New York when severe weather like this is in place, and we get all the traffic managers on it. It's a good communications environment. It works extremely well for us. The other issue is the information side of it. How much do you know? Where do you get your information from, and is it the same picture that everybody else has? The answer to that is no. It's not the same picture. We have very few tools. That's where I think some of our bigger efforts have to be, in providing common tools for people to make shared decisions."

Dispatcher: "What I don't understand is, if the Air Traffic System does not have the tools to deal with severe weather situations like this, why didn't they just default to what the airline wanted to do in the first place, which was to fly where the weather wasn't! Stop trying to do the job for us."

Command Center Specialist: "I wasn't there that day so I can't speak about the situation, but you guys are focusing on the operation of your airline alone. You're not looking at the big picture. The big picture is that when you have weather in the Indianapolis airspace and you move those airplanes into somebody else's sky, they are also working the airplanes that are suppose to be there. So you're pushing additional workload on the controllers that are working in that sector. So you get into sector alerts which leads to miles-in-trail and other restrictions. Some airplanes just can't go that way."

Dispatcher: "Okay, there are times when that is true. But what about this situation here?"

Command Center Specialist: "Again, I can't address this situation, I wasn't on."

Dispatcher: "I think the Air Traffic Manager made a mistake. I think they were wrong."

Command Center Specialist: "If it was slow moving, and we didn't go down the East Coast ???, then we were wrong. But there could be some reasons behind it that I don't know about."

Traffic Manager: "Let me jump on the sword here. If you want me to say that there was a mistake made in this particular case, absolutely. But if you expect us in Traffic Management to stand back and watch the airlines run the Air Traffic System, I'd love to do it, but I'd like video of it also! Because the first time airline XYX takes his airplanes and reroutes them over a fix that airline ABC is using today, there goes our system. We provide balance. You can't say that every decision that's made by the airline is absolutely correct, nor are ours. Somehow, we need to find a way to make it together."

Summary | The scenarios discussed above are all real. It is therefore important to step back and ask how they can be avoided in the future, or at least how their occurrence can be minimized.

Several of the scenarios emphasized that, if you want to change a person's behavior, it is important to give them the information needed to adequately consider the alternatives. Whether the problem is pilots deciding whether to fly direct, dispatchers deciding whether to file a flight on the FAA preferred route or an NRP route, or traffic managers deciding to restrict flights, it is important to ask whether access to a more complete picture will lead to better decisions. It is also important to understand that, to get this complete picture, people may have to talk to each other. It's not always just a matter of displaying data on a screen.

A second point that was made is that there are real constraints in the current system, and that while sharing information may lead to better solutions within those constraints, they still limit decisions. Scenarios like the NRP flights from LAX to DFW, or the NRP flights through Iowa City/Waterloo tell us where those constraints are. An important question is thus raised: Can we change the system to reduce these constraints, through new procedures, through new system architectures or through new technologies?

Thus, in very general terms, the discussions summarized above emphasized the need for:

•  Better mutual understanding of the viewpoints and capabilities of others within the system;
•  The need for increased and more effective communication and information exchange;
•  The potential value of collaboration shared decision making in identifying potential problems and in developing solutions to these problems (both at a programmatic level and in terms of daily strategic planning and the tactical handling of situations that have developed);
•  The importance of making the system less susceptible to impact of the inevitable slips and mistakes that individuals will occasionally make;
•  The importance of understanding where there are significant capacity limitations so that, in the short run they can be dealt with as effectively as possible, and so that in the long run these limitations can be reduced or eliminated.

Finally, the panel highlighted the need for improved feedback from system users to the traffic management system, and vice versa, about how well various aspects of the system are working.