¶ … 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...

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…