ATM Modernization, Business & GA, Commercial, Embedded Avionics

Five 2015 Updates on the NextGen ADS-B Program 

By Woodrow Bellamy III  | December 22, 2015
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[Avionics Today 12-22-2015] 2015 was a major year of progress, learning about equipage challenges and program re-alignment for the FAA’s NextGen Automatic Surveillance Broadcast (ADS-B) Out mandate initiative. Throughout the year, the agency worked closely with the aviation industry through its Equip 2020 initiative to provide education for operators, installers and pilots about what ADS-B solutions are available, what’s required to get in compliance and what airspace will require equipage. 
As 2016 approaches, operators are equipping slowly but surely and manufacturers are ensuring that existing and new customers have all of the information they need about complying. Over the next decade, most of the airspace throughout the globe will be using ADS-B as the primary means of surveillance, including within the oceanic environment. Here is a look back at five of the biggest achievements, challenges and new guidance associated with ADS-B that occurred in 2015.
ADS-B Out ground station. Photo: Harris. 
1. New Guidance
On Dec. 7, 2015, the FAA published revision B to Advisory Circular (AC) 20-165B, which provides guidance for installation and airworthiness approval of ADS-B Out solutions on aircraft. 
According to the agency, AC 20-165B is intended for “anyone who is applying for an initial type certificate (TC), supplemental type certificate (STC) or amended STC for the installation and continued airworthiness of ADS-B Out equipment.” One of the biggest changes featured in AC 20-165B, which supersedes AC 20-165A, is that ADS-B Out transmitters and position source are no longer treated as a major aircraft alternation. Initial approvals are still required, however ADS-B Out installations are to be treated as normal avionics, according to a summary of the revised AC provided by the Aircraft Electronics Association (AEA). 
The AC also features guidance for follow-on installation criteria of a previously approved system and for the reuse of flight test data for follow-on installations of approved systems.
2. New STCs 
The FAA now provides a total list of certified equipment available for operators that need to upgrade their aircraft to get it into compliance with the 2020 mandate within the Equip ADS-B section of its NextGen website. 
The latest update from the FAA shows that there were a combined 14 new STCs and TCs issued for new and existing ADS-B Out avionics in 2015, and three new STCs issued for ADS-B In avionics this year. For example, ACSS earned European TCs for the NXT-600 for ATR 42 and 72-600s, as well as an STC for the NXT-800 on Boeing 757s and 767s. In November, Rockwell Collins achieved a TC for its TPR-901-205 for Boeing 737 NGs. 
The FAA’s Equip ADS-B site also shows the approved position source, aircraft type and approval date for each ADS-B Out and In solution. 
If you’re a Part 25 operator, our recent ADS-B special supplement also provides in-depth guidance on DO-260B ADS-B Out compliance. 
3. Equipage Rates
During the Avionics for NextGen conference in October, experts raised concerns about the numbers crunch associated with the time remaining before Jan. 1, 2020 when ADS-B Out equipage will be mandatory within airspace that requires a transponder today. 
To help assess the number of installation facilities, workers, aircraft downtime and other parameters necessary to get all aircraft that need upgrades compliant by that date, the FAA started publishing a monthly equipage level list on its website.
As of Dec. 1, the agency estimates that between 10-15 percent of the total registered U.S. general aviation fleet is equipped with ADS-B Out, while between 7-8.5 percent of the U.S. airliner fleet is equipped with ADS-B Out. In the month of November alone, 655 total GA aircraft were equipped while 45 total airliner aircraft received ADS-B Out installations. 
The FAA reports its equipage levels as percentages based on estimates of 5,000 to 6,000 airliner aircraft and between 100,000 to 160,000 total registered GA aircraft. Percentages and estimates must be used to account for aircraft that could be operating in airspace that does not require ADS-B Out equipage as well as aircraft that could be retired.
4. Clarity for Airlines on GPS Receivers
In 2015 the FAA Flight Technologies and Procedures Division provided clarity on the type of Global Positioning System (GPS) receivers that can be used as a rule compliant ADS-B Out position source. According to Exemption No. 12555, three different variants of GPS receivers currently in use by operators satisfy the ADS-B Out performance requirements to varying degrees. 
Exemption No. 12555 states that “GPS receivers that comply with FAA technical
standard order (TSO)-C129 can meet the performance requirements over 95 percent of the time, but experience brief outages of performance daily. GPS receivers that comply with the performance requirements TSO-C196 can meet the ADS-B Out performance requirements with the current constellation of GPS satellites, and will experience outages when sufficient satellites are out of service or if there are far fewer satellites.”
FAA has acknowledged that a petition filed by Airlines for America (A4A) showed that navigation receivers suitable for transport category aircraft that would meet the ADS-B Out position source requirements will not be available for purchase or installation in sufficient qualities until closer to 2020. Therefore, Exemption 12555 provides a pass for operators of transport category aircraft from “14 CFR § 91.227(c) (1)(i) and (iii) for aircraft that are ADS-B Out equipped using qualifying GPS receivers when their performance falls below the requirement and backup surveillance is available.”
The exemption expires Dec. 31, 2024.  
5. Privacy Issues Remain
One of the biggest concerns regarding the 2020 ADS-B Out rule that has been repeatedly raised by the National Business Aviation Association (NBAA) is that the equipment transmits an unencrypted real time signal that includes an aircraft’s Mode S transponder code, call sign, aircraft type, position and airspeed. 

During a November educational session on flight tracking in the digital age, National Business Aviation Association (NBAA) Vice President of Regulatory and International Affairs Doug Carr said the organization wants to avoid the possibility of tracking of business jets being used for “nefarious purposes.” NBAA has proposed having the FAA remove Mode S data from the aircraft registry or to allow operators to randomize or change their Mode S codes as necessary. Another option, according to NBAA, is to encrypt ADS-B data, though the organization notes that “this option is complex and still in early analysis stages.” 

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