Cost-benefit analysis of legacy versus next-generation aviation terminal navigation systems

¶ … pros outweigh the cons of airport navigational systems upgrades. Specifically, the study conducts analysis of the perceived costs and benefits of maintaining legacy versus next generation (Nextgen) aviation terminal navigation systems (NAVAIDS). The study tests the hypothesis that the cost-benefit ratio of upgrading NAVAIDs to Nextgen systems justifies the expense when compared to continuing to use existing legacy systems. The null hypothesis is that the cost-benefit ratio of upgrading NAVAIDs to Nextgen systems does not rationalize the expense when compared to continuing to use existing legacy systems. To test this hypothesis, a literature review is conducted of reports in the National Transportation Safety Board database as well as in journal reports and correspondence between agencies regarding Nextgen upgrades in order to determine the extent to which navigational systems were a factor in accidents or present a going concern for stakeholders. The Federal Register's Proposed Provision of Navigation Services for the Next Generation Air Transportation System (Nextgen) Transition to Performance-Based Navigation (PBN) and its attendant request for comments provided ample material for examination regarding going concerns, and data from this collection of comments (366 total) was gathered and assessed so as to provide a better working framework for analysis. Included in the literature review are descriptions of legacy and Nextgen systems, current articles and reports, and federal aviation regulations on the topic. Recommendations based on the findings are provided.

Introduction

When deciding whether to upgrade airport navigational systems, it is important to perform a cost-benefit analysis in order to determine which course (to upgrade or not to upgrade) is the better option (FAA, 2011). Upgrading from legacy systems can be expensive in terms of implementation and training while the added value of the next generation (Nextgen) aviation terminal navigation systems (NAVAIDS) is as of yet unknown aside from the projected estimates supplied by the FAA (Materna, Mansfield, Walton, 2015).

Following the FAA's 2011 request for feedback in the Federal Register on its proposal to upgrade legacy navaids such as VORs to Nextgen's GPS/WAAS RNAV, over 300 comments were provided from the public that ranged from trepidation for safety ("The elimination of the VOR system and reliance solely on GPS for navigation would be a grave mistake") to concern for environmental issues (Bello, 2012). Eliot L. Engel (2012) of the U.S. House of Representatives took the opportunity to respond to the FAA, writing

"While I agree the modernization of our aviation system is necessary to bring it into the 21st century it must also keep pace with the increased number of flights and maintain our technological advancements by implementing new equipment to keep our system the safest in the world. I do have several concerns as the transition takes place. The first concern is that the combination of the Nextgen implementation and the airspace redesign will put an undue burden on the residents of Rockland County. These two changes will direct more flights, closer together over this suburban community. This will directly lead to increased noise and increased pollution. My other concern is that some aspects of the Nextgen implementation may be exempted from the proper environmental review. I strongly object to this. While, it is claimed that Nextgen will lower overall pollution, Rockland County should not be the test case for this. The increase in flights will add to pollution and could exasperate the already too high childhood asthma rate." (Engel, 2012)

The concerns expressed by the Congressman regarding the update are not directly related to issues of safety for pilots and passengers but are rather related to noise pollution (upgraded systems could mean more flights being flown over residential townships) and environmental pollution, which could detrimentally effect the health of children and adults. These are, in other words, safety issues that impact stakeholders on the ground -- and, as a result, can be viewed as issues impacting the decision about whether or not to upgrade systems. As GPS systems will alter routes and raise political issues as well as social and environmental ones (as can be seen from the Congressman's letter -- one among many -- to the FAA), the Nextgen upgrades are not as clear cut or as simple as the FAA's initial proposal (based purely on technical and economic variables) appeared to suggest.

While these concerns may be valid, the cost-benefit analysis of this study focuses not just on such issues as these but also on safety issues and whether Nextgen systems will provide any better safety features and mechanisms than legacy navaids already in place. For example, Jan and Kao (2013) assessed the tracking performance of the GPS Nextgen system and identified the "major concern to aviation authorities" regarding its use -- namely that the GPS signal could be jammed rather easily by radio-frequency interference (p. 6636). Or, as Sueki and Kim (2016) point out, "many vulnerabilities of Nextgen stem from the increased interconnection of systems through wireless networks" (p. 201). Thus, the fact that security measures still need to be addressed regarding these interconnected systems indicates that the upgrade may present more cost and less benefit in terms of safety. Jan and Kao (2013) moreover note that will simple algorithmic retrofitting, the current legacy systems could be enabled with the ability to track aircraft in real-time, just as the proposed GPS Nextgen systems would do -- without the cost.

Background

As Karp (2016) notes, currently the FAA is in the middle of completing "an 18-year ATC modernization initiative encompassing a variety of technologies and procedural changes, all coming under the umbrella of Nextgen." With mega-contracts awarded to companies like Lockheed Martin, tasked with producing an infrastructural piece of equipment called the Terminal Flight Data Manager (TFDM) at a price tag of $344 million, the FAA is spending a substantial amount of money on upgrades that many critics are not seeing the value of (Karp, 2016). The FAA has stated that a full sense of the benefits of upgrading legacy (current) systems to Nextgen will not be felt until 2030 when all the components of Nextgen have come together. In short, according to the FAA, the industry is being broken up and put back together again piece-meal, like a puzzle, and only when the final piece goes in will the picture suddenly make sense to opponents.

The problem with this is that critics already see the picture that is emerging and believe the costs associated with Nextgen outweigh the benefits (Public Submission, 2015). While supporters of Nextgen can point to any number of technological upgrades that make the industry safer, opponents can point to any number of issues or problems that emerge from those upgrades that make the whole initiative seem like a lark -- like little more than an unnecessary exercise in contracting work to companies like Lockheed, routinely and historically known for obtaining lucrative contracts from the federal government (Karp, 2016).

In 2007, the FAA released a Fact Sheet to explain its approach to upgrading airport navigation systems. Nextgen was described as a "wide ranging transformation of the entire national air transportation system -- not just certain pieces of it -- to meet future demands and avoid gridlock in the sky and in the airports" (FAA, 2007, p. 1). Nextgen was designed as a deliberate and total move out of the legacy ground-based systems, which would be replaced by a "more dynamic satellite-based technology" using GPS to show where aircraft are at every second (as opposed to seconds-long intervals of legacy radar sweeps leaving gaps in real-time knowledge of an aircraft's position) (FAA, 2007, p.1). With GPS installed along with a number of other navigation tools, Nextgen would allow aircraft to fly more closely together in more streamlined routes. Some of the major elements of Nextgen systems would include Automatic Dependent Surveillance Broadcast (ADS-B) -- the "backbone of the Nextgen system" as a result of its GPS technology and real-time access to continual surveillance (FAA, 2007, p. 1). As of 2007, the FAA's President's Budget request for ADS-B had reached $564 million (FAA, 2007, p. 1).

Other components of the Nextgen upgrades included the System Wide Information Management system (SWIM), which the FAA identified as the source for "infrastructure and services to deliver network-enabled information access across the Nextgen air transportation operations" (FAA, 2007, p. 1). By 2007, its budget request total stood at $173 million.

The Nextgen Data Communications system was promoted as an improvement upon the voice-only communications of legacy systems and would allow aircraft that are "data-link equipped" to participate in the exchanged of "routine controller-pilot messages and clearances via data" so as to allows traffic controllers to better and more safely monitor traffic (FAA, 2007, p. 1). The budget request total for Nextgen Data Communications by 2007 had reached $126 million.

Other features identified in the Fact Sheet were the Nextgen Network Enabled Weather, the NAS Voice Switch, and the Nextgen Demonstrations and Infrastructure Development. The benefits of these and the other upgrades described above were then discussed by the FAA in somewhat fanciful terms, considering the justification for GPS surveillance put forward by the FAA in more recent years (as well as the actual developments that have emerged -- more flights condensed over the same routes) (Public Submissions, 2015): for example, the FAA asserted that because of Nextgen's Trajectory-Based Operations, "in the future, many pilots and dispatchers will be able to select their own flight paths, rather than follow the existing interstate-like grid in the sky" -- and, the FAA allowed that "what enables this is information" (FAA, 2007, p. 2) -- a purely hypothetical point that has not been proven accurate. If anything, flight routes have become less dynamic (Guy-Ryan, 2016).

According to the FAA (2007), Nextgen would also promote more collaborative air traffic management, reduce weather impacts, "improve airport surface movements" at high density airports by reducing "spacing and spacing and separation requirements" and more effectively managing "flows into and out of busy metropolitan airspace" (p. 2). Yet, as Materna, Mansfield and Walton (2015) showed nearly ten years after the FAA's Fact Sheet was published, even high density airports would be unable to effectively utilize the Nextgen upgrades without further expansion of the airports themselves (p. 137).

Figure 1. High density airports need expansion in order to fully take advantage of Nextgen. (Source: Materna et al., 2012, p. 267).

Regardless of whether the upgrades would have a beneficial or costly effect on the industry and the U.S. economy, at the outset of the initiative, more than $1 billion had already been allocated to the FAA's upgrading plan -- a plan, which the FAA advised in 2015, would save the industry more than $11 billion through 2030. Those savings were said to come from En Route Automation Modernization (ERAM), ADS-B, Datacomm, and Performance-Based Navigation (FAA, 2015). In the same FAA (2015) Fact Sheet, it was revealed that estimates for Nextgen upgrade costs had reached more than $32 billion -- a projected budget covering the years from 2007 to 2030 -- with nearly half of that going to private sector contract costs (FAA, 2015).

Objective

The purpose of this paper is to explore the pros and cons of upgrading navigational systems at airports. The goal is to answer the question of whether the cost-benefit ratio of upgrading the systems justifies the investment.

The study tests the hypothesis that the cost-benefit ratio of upgrading NAVAIDs to Nextgen systems justifies the expense when compared to continuing to use existing legacy systems. The null hypothesis is that the cost-benefit ratio of upgrading NAVAIDs to Nextgen systems does not rationalize the expense when compared to continuing to use existing legacy systems.

Scope

Within the scope of this project and the included cost-benefit assessments, the term benefit may be understood in terms of both safety, strategy, and cost-efficiency. Safety can be understood in terms of all stakeholders -- not just industry leaders, but those within communities under flight paths and those working within the industry.

This study is limited in terms of time, resources, and access to relevant information and data. First, the study is limited in terms of information. The systematic review is conducted using data gathered from the National Transportation Safety Board (NTSB) federal database and its links, such as the FAA Aviation Safety Information Analysis and Sharing (ASIAS) database. The documents released and published on their websites are, however, not the only data sets that will be analyzed for this study -- studies gathered from scholarly databases that are relevant to this analysis will also be assessed.

While this study was intended to primarily serve as an investigation based on information released by the NTSB and its affiliates, whose links are provided directly by NTSB on its database homepage, a review of documents obtained through these databases provided little in the way of answering the hypothesis stated in this study. Airlines for America (A4A), the Flight Safety Foundation and IATA were also consulted for statistical data. In so doing, the study has aimed to include analyses of current articles and reports in order to contrast the limited findings on the NTSB with what other researchers in the field have shown as well as with what stakeholders impacted by the Nextgen upgrades have directly experienced. For these reports, the Hunt Library has been utilized and the appropriate keywords used to conduct searches for the relevant literature. As Figure 2 indicates, issues of safety in U.S. aviations suggest that the cost-benefit ratio regarding Nextgen upgrades cannot be determined by statistical analysis regarding safety. A separate approach that addresses other aspects of "cost" and "benefit" has to be explored -- precisely because U.S. aviations currently provides the safest form of transportation in the nation, according to the NTSB (A4A, 2015).

Figure 2. Airline Safety -- best among modes of transportation in the nation (source: Airlines for America).

Federal aviation regulations are consulted as part of the specific data set utilized for this study.

Study Methodology

This systematic review tests the hypothesis by identifying the relevant body of work pertaining to the issue of legacy versus Nextgen navigation systems for airport terminals. Because few incident and/or accident reports relating directly with navigational systems were found in the National Transportation Safety Board database, key word searches directed the research to the Office of the Federal Register and its 2012 communication: Proposed Provision of Navigation Services for the Next Generation Air Transportation System (Nextgen) Transition to Performance-Based Navigation (PBN). This FAA proposed policy and request for comments from the public provided a look into going concerns regarding Nextgen upgrades and safety features that might impact whether or not to implement designs. In all, 366 public comments were recorded and made available for view. These comments were analyzed and themes identified and categorized, with a correlation analysis conducted to accompany the qualitative assessment of incident/accident studies and articles retrieved from scholarly databases using key word searches.

Literature Review

Bowman's (2012) letter to the Docket Operations, M-30, U.S. Department of Transportation provides a window on the type of going concerns that Fedex had regarding the FAA's policy proposal of implementing Nextgen. The letter identifies several technical problems with the policy proposal: 1) The update proposal would "mandate equipage, equipage that is not offered by major airline airframe manufacturers" (Bowman, 2012, p. 1); 2) the approach is "inconsistent with the concept of PBN to stipulate a specific sensor solution" -- no consideration is given to "other Global Navigation Satellite System (GNSS) constellations that support multiple frequencies for complying with the accuracy and integrity requirements of CAT I approach operations" (Bowman, 2012, p. 1); 3) "GBAS should be identified as a suitable replacement for CAT III Instrument Landing System (ILS) approach operations. It is otherwise assumed that ILS's will still need to be funded from Facilities & Equipment (F&E)" (Bowman, 2012, p. 1); and, finally, the most important issue raised by Fedex indicates that in terms of pragmatism, the proposal falls short where international commerce, trade and shipping are concerned: 4) companies like Fedex

"are spending millions of dollars in training and equipment to exercise RNP AR, which yields a similar accuracy to WAAS CAT I minima. China's Civil Aviation Authority Performance-Based Navigation PBN implementation program states that "RNP will be available on 30% of instrument runway ends by 2012, 100% by 2016, and RNP will be mandated at certain airports." The PBN Roadmaps for Canada, Australia and India support the same timeline for RNP implementation. Fedex operates globally, we must equip our aircraft to be capable of interacting with systems worldwide. Fedex recommends that RNP AR approaches with Fixed Radius (RF) legs are implemented at more runway ends in the conterminous U.S. (CONUS) and Alaska to instill confidence in those operators that have already invested in this technology, rather than requiring them to invest in another." (Bowman, 2012, p. 1-2)

As Vice President of Flight Operations at Fedex, Captain James Bowman's (2012) letter to the FAA carries a significant amount of weight: it is comprised of technical, business and pragmatic and safety considerations that should be well considered by the FAA. The issues show that upgrading to Nextgen systems is essentially an inevitability -- however, the upgrade should be performed in a manner that provides cohesion and uniformity rather than more problems for carriers, pilots and airports, all of whom will have to contend with different systems and designs within a larger global context when various instruments are placed into use at the same time.

Among the 366 respondents to the FAA's request for comments on its Nextgen Proposal was a brief letter from Schmidt (2013) who identified a number of safety issues related to GPS technology in aviation and the abandonment of VORs. Schmidt (2013) argued that safety is very important in aviation and that "a primary component of safety is redundancy. Eliminating a large percentage of the nation's primary air navigation system eliminates a primary component of safety. Eliminating VORs is a bad idea." Schmidt's (2013) acknowledgement of the benefits of GPS and WAAS is important, as he notes that both have been able to "serve the aviation community very well." His problem with the Nextgen proposal is mainly that "GNSS navigation is susceptible to many forms of failure, ranging from scheduled outages, to unavailability of satellites, to interference, to intentional sabotage. These failure modes are not hypothetical. GNSS systems often fail" (Schmidt, 2013). He supports this argument with personal experience of GNSS failures "several times in just the past several months" further arguing that "as GNSS evolves into the primary navigation mode for U.S. airborne navigation, it is imperative that the current primary system (VORs) be available as a failsafe" (Schmidt, 2013). Schmidt's final point identifies a substantial cost related to the FAA's Nextgen proposal, a purely practical consideration that raises question about what will happen to carriers who cannot update to GPS systems: "many aircraft are not yet and may never be equipped with GPS receivers. Eliminating the VOR airway system will render these aircraft debilitated or useless for IFR and even some VFR flight" (Schmidt, 2013). Thus, the upgrade proposed by the FAA, according to this respondent, could do much more harm than good in numerous areas -- from safety to practicality to risk management and prevention.

Testimony before the Subcommittee on Aviation, Committee on Aviation, Committee on Transportation and Infrastructure, House of Representatives, published by the United States Government Accountability Office (2011) revealed that "delays have resulted in increased costs and reduced benefits" for stakeholders in the aviation community and that "going forward, FAA must focus on delivering systems and capabilities in a timely fashion to maintain its credibility with industry stakeholders" (p. 3). However, the timeliness of acquisitions and implementations has not been adequately upheld and nor has the FAA been forthcoming in terms of ensuring that its flight routes' environmental safety (Will, 2013). Noise pollution has negatively impacted several cities where new routes have been adopted as a result of Nextgen: Boston, New York, Baltimore, Phoenix, San Jose, Santa Cruz and San Francisco have all seen escalations in noise pollution. Low-flying aircraft have also plagued Palo Alto, where Dremann (2014) reports that 4/5ths of flights over the region are in violation of the 8000 ft. elevation rules regarding aircraft approaches.

Accidents and Safety

In terms of research on accidents and safety, the study by Ho and Burns (2003) indicates that navigation systems do play a part in reducing the risk of catastrophe occurring. However, these are isolated incidents, and as the study notes, part of the reason for the risk of crash comes from the fact that there are too many instruments for pilots to choose from. Accidents such as midair collisions are infrequent occurrences; nonetheless, they have happened in the past and the 2002 collision of a DHL cargo jet with a Russian airliner revealed the extent to which navigation systems issues do prevail: The Russian plane, for instance, was alerted both by the ATC and the onboard TCAS systems of the risk of impending collision -- yet, had only one navigation instrument been in use, the complication that ensued could have been avoided (which is the crux of Bowman's letter to the FAA -- too many instruments and designs lead to confusion in the skies). As for the Russian airliner-DHL plane collision, the Russian pilot made a decision to follow ATC directives. The pilot ignored the TCAS maneuver recommendations, adhered to ATC recommendations, and a crash occurred. Human factor was certainly an element in the crash -- and today's Nextgen systems are being implemented in order to reduce the risk of human factors playing a part in navigations. In this sense, Nextgen navigation systems are being utilized to take the risk of human error out of the equation. In fact, the TCAS's worldwide usage and the up-and-coming ACAS X indicate that the technology exists to help limit the extent to which human factor risk can become an issue (Kochenderfer et al., 2012).

However, TCAS systems are more than 40 years old, and Nextgen systems such as ACAS X have been designed to update the manner in which logic is "used to select pilot advisories" and control navigation options made complicated and hard to adjust with the introduction of surveillance information from new sources (Holland et al., 2013). As Jeannin et al. (2014) note, the ACAS X is a Nextgen system currently being installed in planes around the world and tests have shown that it is able to reduce the likelihood of collision by 59%, the need for alerts by the same amount and the frequency of disruptive alerts by nearly 30% (Holland et al., 2013).

In terms of ground navigation, the FAA's push for ADS-B Nextgen navigation systems is viewed to be highly impactful on industry's safety and efficiency. As reported in 2016 by The Economist, airplanes that are outfitted with ADS-B transponders work with GPS satellites to give a precise indication of location every second -- unlike legacy radar system. The ADS-B system can, moreover, couple location information with data relating to the plane's flight number, trajectory, speed, and maneuvers. All of this information is signaled by the Nextgen systems with a 150-mile radius: "By knowing at any instant exactly where they are relative to other aircraft in the sky, planes so equipped can travel closer together without fear of colliding. They can also take more direct routes to their destinations, instead of zig-zagging their way from one control tower to the next. That saves fuel and time, while minimizing aerial congestion" (The Economist, 2016). In this regard, Nextgen systems are maximizing air space, reducing times in the sky and conserving fuel. Opponents of Nextgen systems argue, on the other hand, that the reduction in emissions is relative: the actuality is that with air spaces and flight paths condensed, Nextgen systems allow more flights to take place -- which really puts more not less emissions into the atmosphere -- and does so over tighter regions instead of dispersing the emissions over a range of regions/routes, which in turn raises the risk of destroying the environmental health of those regions.

Sueki and Kim (2016) point out that the "critical part of the Nextgen, Automatic Dependent Surveillance -- Broadcast...is an easy target for attackers" precisely because it "transfers essential information via wireless network without encryption" (p. 201). This is an especially troubling finding in the Digital Age where cyber warfare is a continual threat at all times. If this kind of information can be hacked and/or manipulated, it could become a catastrophe waiting to happen. Thus, even for passengers, crew and the industry as a whole, Nextgen risks associated with safety could be assessed as far greater than the profits foreseen by the industry as a result of streamlining routes and putting more planes in the sky at a time.

Jan and Kao (2013) assert in their study of radar tracking versus GPS navigation systems that the former is a needed back-up in the event of a GPS outage (such as would result from an attack on satellites or via radio-frequency interference. Jan and Kao (2013) note that in order for the current radar system to meet ATM system levels of performance, it would have to be enhanced with a special tracking algorithm. This would allow the current legacy system to remain a viable and suitable navigation system in the event of a GPS blackout. The researchers use the Kalman filter as a baseline for evaluating their algorithm and find that the legacy system can and does meet the standards for surveillance should Nextgen GPS fail. This finding indicates that not only is legacy still relevant, it may even be necessary in the event that GPS tracking cannot perform. Moreover, it indicates that a total navigation upgrade is not even required but rather that a simple algorithm may be applied to the current navigation system so that it is brought up to standards presented by ATM systems.

Approach and Landing Accident Reduction (ALAR) has been the focus of the Flight Safety Foundation (FSF) for years. Approach and Landing accidents have been reduced in recent years thanks to "safety products and international workshops" geared towards educating pilots and controllers about issues related to these types of accidents (FSF, 2015). As FSF (2015) notes, in 2009, there were 17 major aircraft accidents involving aircraft weighing 5,700kg or more -- and 9 of those accidents were ALA related -- less than half of the number the previous year. Thus, the issues related to ALAR are deemed substantially based in human factors -- where education, training and safety products have helped to significantly reduce these numbers -- and less so on technological systems issues.

Cost

According to testimony given by James May, President and CEO of Air Transport Association of America, Inc., before the Subcommittee on Aviation of the House Committee on Transportation and Infrastructure (2009), "the current ATC system limitations impose significant costs on society in general, and the airline industry in particular. The Joint Economic Committee estimates air travel delays impose $41 billion annually in costs on the U.S. economy" (p. 2). May's perception of legacy systems is that they are responsible for these delays -- though outside of his testimony there is no evidence indicating that travel delays are the direct or even indirect result of legacy navigation systems. Nonetheless, May's testimony indicated that unless Nextgen upgrades are implemented, the cost to the U.S. economy of continuing to use legacy systems would only increase. May's assessment is based mainly on the FAA projection that flight operations will essentially double by 2025 from where they were in 2007. This projection, however, could easily be impacted by any number of economic, social or political variables, causing it to be revised downward. Thus, justification for upgrades, according to May's testimony, is based on hypothetical future scenarios/calculations and no-evidence-based claims.

On the other hand, the cost of implementing ADS-B Out avionics on planes could prove to outweigh the benefits, according to Thurber (2015). With a minimum investment of $6,000 per installation of ADS-B Out technology, the price is deemed "far too high for many GA operators," as AOPA President Mark Baker told the FAA (Thurber, 2015, p. 8). Considering that "the general aviation fleet includes at least 81,564 certified, piston-powered, fixed-wing aircraft that are valued at $40,000 or less, and that GA owners have no way to recoup their costs," Baker points out "there are alternative means" to adopting a GPS strategy navigation system that the GA community can rally behind -- but that ADS-B is not it (Thurber, 2015, p. 8).

However, not updating systems, according to the FAA would cost the U.S. economy $22 billion a year "in lost economic activity" -- a figure which the FAA expects will rise to "$40 billion by 2033" if airport navigation systems are not upgraded (Materna, Mansfield, Walton, 2015, p. 136).

With the President's Budget for ADS-B alone already at half a billion dollars in 2007, the Nextgen upgrades are proving to quite expensive (FAA, 2007) -- as Thurber (2015) notes. The issue is complicated by the acknowledgement of the FAA regarding current airports' ability to really take advantage of Nextgen systems in order to condense flights and generate more revenue by putting more planes in the skies on less circuitous routes (Materna, Mansfield, Walton, 2015).

Looking into the future, other considerations about funding and cost emerge as a result of spaceport-airport mergers, as demand for commercial space operations grows. According to Materna et al. (2015), the funding needed to support commercial space operations and maintain them is estimated at $1 billion per year -- simply to keep the Unmanned Aircraft Systems (UAS) from being inhibited. In order to fund the expansion of the UAS sector and to facilitate its growth, the FAA will require further monetary assistance from the federal government -- and in a time of uncertain economic activity (with the possibility of a recession looming on the horizon), the question of where these funds will come from or whether they will be available at all in the future remains one that is unanswered.

Figure 3. Commercial spaceports equipped for UAS.

The issue of cost is further exacerbated by contradictory indicators. For example, the International Air Transport Association "expects 7.2 billion passengers to travel in 2035, a near doubling of the 3.8 billion air travelers in 2016" (IATA, 2016). Yet, as Materna et al. (2015) show, since 2007, cargo traffic at the world's busiest airports has been in decline. For Anchorage International, the decline is at 25% of traffic -- caused mainly by the "increase in belly capacity on Boeing 777" (Materna et al., 2015, p. 135). Moreover, economic contraction on a global scale with industrial deceleration indication recessionary red flags suggests that the type of growth foreseen in the Compound Average Growth Rate is not in step with statistical figures representing underlying economic currents. As the IATA observes, economic growth is the only factor that will carry this expected projection -- and if growth is slowed, these numbers will not be met (IATA, 2016). Thus, while optimistic projections indicate that future traffic will be higher, current rates suggest a different picture altogether -- which makes justifying necessary expansion problematic. This problem is increased when the issue of cost is touched upon -- as Materna et al. (2015) show, "transportation infrastructure funding has always been challenging, but with infrastructure costs rising and funding limited, airports have been forced to dealy or scale back capital infrastructure projects" (p. 132). Where funding will come from, short of federal intervention, is difficult to surmise. Bond sales make up 36% of funding sources, and airports that desire to maintain strong bond ratings have to meet specific revenue goals -- "between 125% and 150% of expenses plus debt service" -- in order to maintain high-level investment worthy status (Materna et al., 2015, p. 132).

With traffic down, meeting those revenue goals could prove increasingly more difficult -- and as raising future capital through bond sales depends upon revenue goals being met, the problem of how to sustain growth could spiral out of control even as the cost of implementing Nextgen increases without the utility of implementing Nextgen adding any substantial financial incentive (Materna et al., 2015). Thus, the rise of lobbying power as a supplement to user-fee systems and in the case of Nextgen upgrades an essential element to their implementation now plays a dominant role in the life of the airline/airport industries -- not just in the U.S. but in the world over (Holloway, 2008, p. 247). However, compared to the budget allocated to the EU's Nextgen upgrades via SESAR -- "set at $2.9 billion" -- the projected costs of $32 billion for upgrades in the U.S. are more than 10 times that of the U.S.'s European counterpart. Justification for this figure is indeed problematic as Materna et al. (2015) indicate considering current trends and airport capabilities.

Figure 4. Funding sources for airport costs.

Environmental Impact

Thus, one of the drawbacks of Nextgen navigation systems is also one of its positives -- and the way in which it is viewed depends upon the stakeholder. For those in the industry, the ability of Nextgen navigation systems to improve "airport operations, trajectory management, system-wide information management (SWIM) and ease of coordination for aerospace operators" has enabled the industry to see an "increase in the density of flights" at any given time over any given region (Blasch, Paces, Kostek, Kramer, 2015, p. 7). Yet, for stakeholders on the ground -- those living in communities that will see an increase of air traffic over their neighborhoods, the concerns are real: noise and environmental pollution to the atmosphere are issues frequently expressed in the registered responses of the public to the FAA proposal in the Federal Register (Public Submission, 2015).

As Guy-Ryan (2016) reports, Nextgen navigation systems are creating problems for people on the ground while creating solutions for people in the skies. This complexity of results for stakeholders makes assessing the cost-benefit ratio of implementation all the more problematic. For instance, as the FAA points out, the new Nextgen systems allow for planes to be monitored at all times as opposed to the 8-10 second sweeps of the old radar system (GPS technology gives a constant view of the planes in flight). Nextgen also allows for more flights to take place in more direct routes, freed from having to fly over grand equipment. GPS infrastructure allows for planes to travel in more direct routes. With planes being "positioned more closely together, creating new flight path opportunities," the industry is able to benefit immensely (Guy-Ryan, 2016). People in communities now situated directly under the "barrage of overhead flights," however, tell a different story: they speak of having to reinforce windows with Plexiglass to keep the noise out, of pollution, and of noise complaints spiking "2,500%" in Nextgen's new, condensed flight path regions (Guy-Ryan, 2016).

The environmental concerns that would result from Nextgen systems' ability to condense flights over a given range were brought to the attention of the FAA in the 366 responses from the public. The following is a sample of the objections raised by the public:

"Airline profits come before the peace and quiet of citizens" (Brandeis, 2014).

"Non-stop plane noise all day and all night" (Frank, 2014).

"Constant airplane noise, every 30 seconds another plane flies by" (Christianos, 2013).

"Since implementation of Nextgen affecting the incoming planes to New York's Laguardia Airport, the quality of my life has deteriorated and I am facing anxiety and stress due to the noise and pollution (Weiselman, 2012).

"The elimination of the VOR system and reliance solely on GPS for navigation is a grave mistake" (Bello, 2012).

"I live in Williston Park and can't deal with the constant airplane noise every 30 seconds. The planes fly directly over my house and extremely low. My quality of life has dramatically changed. I am pregnant and depression has set in due to the plane noise. It is awful!!!!! The noise keeps me up at night. During the day I avoid leaving my house and try to drown the airplane noise by blasting the music in my house. My family is suffering along side me. I have lived here for 13 years and love my community. However, if this continues I will be forced to move. I dread that day, but my sanity is at stake here. Something needs to be done. I want this to stop. It feels like I live in a nightmare. I know that planes need to be in our skies, but not so low and in one constant path. Something needs to be done!!!! People are being affected!!!!!" (Salinas, 2012).

The issue of low-flying aircraft clearly has a social impact that registers in degree of severity alongside the environmental impact -- and it apparently is one that the FAA did not consider. Low-flying craft are extremely loud and disruptive to community life, and with several respondents to the FAA's proposal citing a sharp decline in quality of life, it is an issue that brings a high degree of negative cost to the Nextgen upgrades -- one that could lead to severe blowback in terms of negative will towards the industry overall, which could impact political will and economic outcomes.

Finamore (2012) wrote to the FAA following its request for comments, stating that on October 20th, 2011, when Phase 2A of the Airspace Redesign was formally implemented, the community of Nassau County, New York, was forever changed "due to aircraft noise and pollution." Finamore (2012) cited the confusing language of the Bill #HR 658 as essentially to blame for pulling the wool over voters' eyes -- and that now, a year after implementation, the reality is plain to see: "increased flight density using concentrated tracks at lower altitudes that characterize Nextgen procedures" will ensure that "our environment will only get worse." Finamore (2012) acknowledges that improvements may be needed in the aircraft transportation system, but he expresses great concern that those improvements should come at the expense of stakeholders' quality of life on the ground.

The point made by Finamore (2012) that improvements in the aircraft transportation system are justified may be rhetorical -- but it is a point that should be addressed, as it relates to the cost-benefit ratio of upgrading systems. But as Jan and Kao (2013) state, such upgrades that provide safety and continuity can be achieved with relatively little alteration in the current system.

From assessment of the 366 comments published by the FAA in response to its proposal, it appears that the upgrades are felt most negatively by those communities directly beneath the new flight paths. Thus, while the paths open up new opportunities for carriers and airports to move traffic more quickly, they present significant challenges for stakeholders on the ground who must bear both the noise and environmental pollution from the planes' exhaust.

Social

The social cost of the upgraded systems is evident in the numerous complaints registered by the FAA. A clear and uniform image emerges -- namely that the upgraded systems are benefiting the companies contracted to perform the work (such as Lockheed Martin) and those members of the industry able to utilize the systems -- but for individual stakeholders who do not stand to profit financially from the upgrades, the situation has quickly become intolerable.

In terms of the upgrades' ability to reduce landing and take-off mishaps, even this has been called into question, as Schmidt's (2013) comments revealed. The technological benefits of GPS in other words do not necessarily mean that the technology is a good fit for the aviation industry -- and while it can be helpful in some regards, it should not be relied upon as a fail-safe way forward (Schmidt, 2013).

The social ramifications of these upgrades are evident in the reports primarily surrounding stakeholders' desire for quality of life within communities on the ground beneath flight paths generated by Nextgen. On the opposite side of the spectrum, however, social ramifications of Nextgen upgrades can be measured in terms of quicker and more direct flights, making flight schedules better and giving air travelers and cargo shippers more flexibility. The trade-off in terms of social dimensions of the issue is again situated in terms of those who are positively impacted vs. those who are negatively impacted. The issue of why one set of society should benefit at the expense of another set does not appear to adequately serve the social notions of equality and fairness embedded within the constitutional fabric of modern life. Moreover, these social repercussions are intertwined with the political repercussions and fallout of the FAA's upgrades as well.

Engel's (2012) letter, for instance, indicates that as a representative of constituents situated beneath a flight path, he is responsible for voicing and representing their concerns and bringing changes to legislation if need be in order to ensure that the FAA is meeting all environmental requirements -- which per the comments made is as of yet not the case. However, the federally mandated upgrades signifies that a greater political context is at work -- one in which Nextgen systems have been legislated and now must be implemented, regardless of the actual costs and/or benefits. The picture that emerges for a review of the available literature pertaining to Nextgen's social and political outcomes is one in which the merger of business and state is allowed and in fact federally mandated so as to provide better technological advantages that many researchers and workers in the industry describe as having several shortcomings and offering inadequate protections (Schmidt, 2013; Jan, Kao, 2013).

Political

Judi Bosworth (2012), Nassau County Legislator, District 10, wrote in response to the FAA's request for comments to its proposal, stating "that the improvements should be done with a full understanding of any harm that may be done to the families living under the new flight patterns and under the new procedures." Her request of the FAA correlates with that of other members of the community, such as Finamore's (2012), in which the aim is to urge "rules associated with section 213 of Bill #658 be structured to allow the FAA the flexibility to streamline the Nextgen program but still provide for environmental studies of the programs." Yet, addressing the environmental impact is only one aspect of the social issue that political representatives now face -- the other issue is quality of life and its evident deterioration in the face of increased noise levels, more frequent traffic overhead, and lower flying planes.

Politically speaking, the Nextgen upgrades indicate an apparent conflict of interest. The rise of special lobbies and corporate lobbying among Congressmen have become a focal point of the Trump campaign (Durden, 2016) and blowback could be felt here as well, further aggravating the issue of funding if ties are cut between politics and lobbying.

With the Century of Aviation Act 2003, the performance-based Nextgen systems have already been mandated, and the FAA's Joint Planning and Development Office is responsible for overseeing "research, planning and transition" (Holloway, 2008, p. 247). However, the "political will to change" is the most important variable in the success of the Nextgen implementation project -- and if the social, environmental, economic and technological aspects of the project become too problematic over the course of the next few year, the political will to change could potentially be reversed (Holloway, 2008, p. 247). Already, community members have successfully moved governor Cuomo to order a noise compatibility study to address the noise complaints from residents impacted by the new Nextgen flight paths out of Laguardia (Al-Muslim, 2013). The fallout from more noise complaints from residents directly impacted by low-flying routes could potentially lead to a catastrophic derailment of the Nextgen program -- especially if it results in further delays, which will trigger a chain effect of stalled acquisitions, higher maintenance costs, and a ballooning budget resulting in considerable government waste and inefficiency.

Technology

Legacy systems include terrestrial-based systems, such as, Instrument Landing Systems (ILS), Very High Frequency (VHF) Omnidirectional Range (VOR) and Nondirectional Radio Beacon (NDB). In contrast, Nextgen systems couple space-based Global Positioning Systems (GPS) with Distance Measuring Equipment (DME) systems located at airport terminals. As Schmidt (2013) observes, the VOR should be a standard back-up system in case of Nextgen failures, as he notes are often the case with GPS and GNSS systems.

Globally, the technological issues associated with systems upgrades have taken different courses. In Europe, the EU developed the Single European Sky (SES) legislation in order to promote institutional overhaul. Out of the SES has come the "functional airspace blocks" design, inspired by traffic flows as well as the development of Nextgen ATM technology, described by Single European Sky ATM Research (SESAR) (Holloway, 2008, p. 247).

The current legacy ATC system was adopted in the postwar years and has been in use for over half a century. It is based on voice communication navigation using ground-based aids with radar surveillance or in some cases "procedural separation" (Holloway, 2008, p. 248). The Nextgen system is focused on utilizing modern satellite-based GPS navigation systems. The ICAO's projections regarding commercial flights indicate that the number of aircraft departures in 2005 will have doubled by 2025 (from 25 million to 50 million). While any number of factors could impact these numbers -- from global recession to World War to Boeing's 777 -- the role that technology will play in the Nextgen upgrades remains one that will be enriching for the producers contracted to assist in the upgrades.

Databases and Records Searched

Statistics were gathered from the following resources: Airlines for America (A4A) (formerly Air Transport Association); Flight Safety Foundation (FSF); International Air Transport Association (IATA) and other applicable industry and aviation trade journals; interpretation and analytical review of reports from NTSB Accident Reports. The database maintained by the Office of the Federal Register was used primarily for gathering information related to the FAA's Proposed Provision of Navigation Services for the Next Generation Air Transportation System (Nextgen) Transition to Performance-Based Navigation (PBN) and the attendant 366 comments submitted by the public and public officials. These comments provided substantial qualitative information regarding the perceived cost-benefit ratio related to the Nextgen upgrades.

Variables Evaluated

Variables evaluated for this study are those related to the perceived cost and benefit of Nextgen upgrades and thus include:

Safety: Issues reported related to legacy and/or Nextgen systems are included as variables in this study. Negative issues are categorized as costs and positive issues are categorized as benefits.

Environmental Impact: Issues related to how Nextgen is perceived to negatively impact the environment are categorized as costs. Issues related to how it is supposed to be better for the environment than the current legacy allows are categorized as benefits.

Quality of Life: Stakeholders citing a decline in quality of life either explicitly or implicitly within registered responses to the FAA's proposal for Nextgen upgrades are categorized as costs.

Political Consequences: These are largely implicit and surmised via interaction with the texts gathered from the searched databases as well as from a cursory assessment of the current political climate, which is very turbulent on the eve of the presidential election, considering that the country could go in one of two directions depending upon the outcome of the race. Either of these two directions could have very impactful results on the Nextgen upgrades.

Financial Cost: The actual financial costs of Nextgen, though quantifiable, are still relative and therefore somewhat qualitative in nature, as there is no real answer to the question -- how much is too much? Thus, these costs are only categorized as costs to the extent that they are viewed as an impediment: for example, costs of upgrading are categorized as "costs" if they oblige carriers to take a loss, the public to take a loss, the federal government to take a loss, or airports and the industry overall to recognize a loss. Current FAA projections indicate that no such losses will be recognized because of the savings that the upgrades will allow stakeholders to realize. To the degree that an assessment can be made, these costs are included as variables in this study.

Determining the Perceived Cost-Benefit Ratio

Because of the subjective character of the perceived cost-benefit ratio, data was primarily most useful when taken directly from the 366 responses of the public to the FAA's proposal. These were categorized according to the variables described above and tallied appropriately.

Data obtained from the NTSB and other databases were used to provide a qualitative framework, while correlation analysis was used to generate an assessment of the 366 responses to the FAA's proposal.

Variables collected from the 366 respondents were categorized according to the issues raised within the text: of the 366 responses, virtually every one was either implicitly or explicitly related to the issue of quality of life. Several Nassau County legislators filed form responses raising the issue of environmental safety. Technological safety was a common variable found in the responses, and political impact was an implicit variable in several responses as well. Financial costs were also cited in numerous responses, such as the comment by Scott (2012), which noted that the region affected by Nextgen in Nassau "is one of the highest tax paying areas in the state" and that "real estate and revenues in Nassau County are suffering" as a result of the low-flying aircraft, the noise and pollution.