ASCI 638 Assignment 3.4

The primary goal of NextGen can be summed up simply as modernization of the National Air Space (NAS) (FAA, n.d.).  Being more specific, the goals are enhanced safety, reduced airspace and terminal congestion, reduced environmental impact, and improved tower to cockpit communications.  The use of satellite weather monitoring in conjunction with advanced radar and satellite based aircraft monitoring allows for more efficient routing with each aircraft receiving an individualized route as opposed to a standard route.  This affects all phases of flight particularly approach, where the aircraft will be vectored on final with a continuous descent profile thereby saving fuel though the avoidance of stepped transitions as well as eliminating or at least minimizing time in pattern.  An additional benefit is reduced noise pollution and exhaust emissions for communities adjacent to the airport.  Metered pushbacks as opposed to the current system of first come, first served serves to minimize taxi time and taxiway congestion, also reducing fuel consumption and positively impacting the environment through the reduction of hydrocarbons (FAA, n.d.). 

One of the key integration factors of UAS operating in the NAS is sense and avoid capability.  The lack of an on-board pilot, while creating numerous design and capability benefits, creates the single biggest hurdle to an effective sense and avoid capability and presents a credible safety concern for UAS operating in the NAS.  se and avoid technology is developing rapidly and according to the Air Force’s sense and avoid program manager the biggest hurdle is not technological, it is FAA policy (Insinna, 2014).  The sense and avoid technology needed varies with the type of aircraft and its’ operating environment, for example, small UAS operating strictly in line of sight can effectively rely on the pilot or operator (Yamaha 2013), smaller UAS, such as the Raven, may eventually utilize a system incorporating on-board sensors combined with ground based radar,  while the most promising combination for larger UAS, such as the Global Hawk, will likely rely on a system integrating traffic collision avoidance system (T-CAS), automatic dependent  surveillance-broadcast (ADS-B), radar, and light detection and ranging (LIDAR) (Insinna, 2014).  All of which are mature or maturing technologies.

Another significant safety concern is that of a lost link scenario, that is a scenario where a UAS loses the control link with the ground control station (GCS) and subsequently the aircraft pilot or operator.  This can be caused by a variety of factors ranging from terrain or weather interference, to mechanical failure, or in worst-case scenarios, purposeful hacking (Paganini, 2013).  Larger or more advanced military UAS such as the RQ-170 utilize sophisticated lost link protocols.  Upon detecting a lost link scenario, the RQ-170 is designed to autonomously follow a pre-established profile until contact is reestablished, due to its’ highly classified nature, the RQ-170 is also equipped with a self-destruct feature (Carr, 2011).  Other less sophisticated UAS , such as the Yamaha RMAX utilize a simple hover and land protocol (Hanlon, 2004).  In any event, lost link protocols will need to be tailored to the specific UAS’ operating parameters and  prevailing FAA requirements.  Just as with sense and avoid technology there is no one size fits all answer.

A significant human factor consideration is loss of a direct pilot, tower verbal interface.  Traditional air traffic control methodologies rely on extensive verbal communication between the tower and pilot and much of this interface is either not needed or not practical with UAS.  NextGen begins part of the transition with  datacom protocols using digital messages instead of voice to transmit electronically much of the data and instructions that were previously communicated via voice (FAA, n.d.).  MITRE Corporation’s UAS sense and avoid technology, which sends a synthesized voice message to air traffic controllers in the event of a lost link scenario, though experimental, is receiving much attention (Van Cleave, 2011) and also lends an human, albeit artificial, touch to what would otherwise be a sterile electronic environment. 

Integration of UAS into the NAS concurrent with the introduction of NextGen will change the NAS forever and the successful combination appears to be gravitating towards a mixture of electronic and human elements.