ads-b – where are we now?

March 25, 2019

At heart, ADS-B is the new way to manage air traffic. But how does it exactly work? Where does the legislation stand? Steve Nichols reports

It has been a couple of years since we had a detailed look at ADS-B. So what is the current legislation and where are we now? But first, what exactly is ADS-B?

The acronym ADS-B stands for Automatic Dependent Surveillance – Broadcast, which on its own is pretty meaningless. ADS-B is “automatic”, because requires neither pilot nor other inputs. It is “dependent” because it depends on data from the aircraft’s navigation system.

Pioneered originally in the USA, an ADS-B-equipped aircraft finds its own position using a global navigation satellite system (GNSS), typically GPS, and periodically broadcasts this position and other information to ground stations and other aircraft equipped with ADS-B.

ADS-B-equipped aircraft broadcast their precise position in space via a digital datalink (the global interoperable frequency is 1090MHz) along with other data, including groundspeed, altitude, and whether the aircraft is climbing or descending. This broadcast capability is sometimes known as a “squitter”.

ADS-B receivers that are integrated into the air traffic control system or installed aboard other aircraft provide users with an accurate depiction of real-time aviation traffic, both in the air and on the ground – although this does require additional equipment to be installed on the aircraft.

Unlike conventional radar, ADS-B works at low altitudes and on the ground, so that it can be used to monitor traffic on the taxiways and runways of an airport. It’s also effective in remote areas or in mountainous terrain where there is no radar coverage or where coverage is limited.

One of the greatest benefits of ADS-B is its ability to provide the same real-time information to both pilots in aircraft cockpits and ground controllers; so that, for the first time, ADS-B equipped aircraft can both “see” the same data, as long as all aircraft in the vicinity are similarly equipped.

To ensure that the system is as compatible as possible with both older and newer technologies ADS-B can be used over several different data link technologies, including Mode-S and 1090MHz data link (in Europe).

The great thing about ADS-B is its automatic nature – the pilot concentrates on flying the aircraft and the system merrily transmits his position without any mechanical intervention.

It also benefits from its relative low cost when compared to other surveillance systems, such as radar, its high accuracy, and the fact that it can also support other airborne surveillance applications, which will enable many future updates.

The safety benefits of ADS-B are huge and include improved visual acquisition, especially for general aviation under visual flight rules (VFR) and reduced runway incursions.

While ADS-B therefore offers air traffic controllers useful information about aircraft in their area, some ATC providers were not convinced that it is currently suitable for use in high traffic volume areas, such as in UK and Northern European airspace.

In the US, ADS-B equipment can also support Traffic Information Services -Broadcast (TIS-B), whereby details of all traffic known to an ATC system can be transmitted back to suitably-equipped aircraft.

There are two commonly recognized types of Automatic Dependent Surveillance for aircraft applications.

ADS-B Out transmits GPS-based position and other aircraft or vehicle information and implementation is now mandated in 2020 (more of that later). ADS-B In allows transmitted signals to be received by other aircraft as well as ground stations, but this is not part of the 2020 mandate.

There is no mandate for ADS-B “In.” However, this optional “In” capability — which receives the tracking data for display in the cockpit — should be a popular upgrade, since it can clearly enhance situational awareness by giving pilots a view of the same basic traffic data that ground controllers are monitoring on their scopes.

Additionally, in the US, FAA inducements for adding ADS-B “In” include free datalink weather and various other flight information services.

But while ADS-B is quite well established in the USA, over here in Europe pilots might be forgiven for being confused.

The European Commission (EC) issued a notice of proposed rulemaking (NPRM) announcing its intent to mandate carriage of Automatic Dependent Surveillance – Broadcast (ADS-B) transponders by 2015. This was to apply to all aircraft, both European and non-European, but those weighing less than 12,500 pounds and with cruise speeds below 250 knots was to be exempted.

But the EC then delayed the mandate for ADS-B out in its airspace, with the new dates being June 8, 2016, for new aircraft and June 7, 2020, for retrofit.

This applies to aircraft with a civilian registration operating IFR/GAT in Europe and with a maximum certified take-off mass exceeding 5 700 kg or having a maximum cruising true airspeed capability greater than 250 knots.

These are required to carry and operate Mode S Level 2s transponder(s) with Mode S Elementary Surveillance (ELS), Enhanced Surveillance (EHS) (for fixed wing aircraft) and ADS-B 1090MHZ Extended Squitter (ES) capabilities.

The revised date for retrofits is more closely aligned with the U.S. ADS-B out mandate that requires the equipment to be operational in aircraft that fly where transponders are currently required after midnight on Dec. 31, 2019.

Not surprisingly, there is a big push by manufacturers to get ADS-B equipment retrofitted. Rockwell Collins says it doesn’t expect the mandates to be delayed and is urging owners to move head now, saying ADS-B is a cornerstone of future airspace modernization programmes.

Aaron Child, Principal Marketing Manager, EuMEA for Rockwell Collins, said: “We’ve seen the pace of ADS-B Out upgrades increasing. However, thousands of business aircraft remain to be equipped so while we’re encouraged with what we are hearing from the market we still have lots of work ahead of us to get everyone equipped by 2020.

“For in-service aircraft, we are focusing on ADS-B Out equipage at this time. Operators will not see benefits of ADS-B In until a critical mass of aircraft are equipped for ADS-B Out.”

“Customers in Europe will be limited to traffic only applications as FIS-B broadcasts providing weather and airport information are only available in the United States on 978MHz UAT. Furthermore, ADS-B In traffic applications are not all fully defined nor implemented in both Europe and the USA.”

Rockwell Collins says it has developed airspace modernization packages for Pro Line 21-equipped King Air and Hawker aircraft. The company says the packages are attractively priced compared with buying each upgrade individually.

Child concluded: “Start discussing upgrade options, costs and aircraft downtime with your maintenance providers today. Procrastination will put you in long queues for the upgrade, higher costs, and risk of non-compliance when the mandate takes effect; effectively grounding their aircraft.”

Honeywell Aerospace is also engaged in a big ADS-B marketing push. While the 2020 mandate does not include ADS-B In, it says there are significant benefits for aircraft that are equipped with it.

At present, aircraft crossing the ocean at altitudes commonly used by most airlines are required to stay in a track at a given flight level with defined time-based separation “in-trail,” an approximately 80 nautical mile buffer, between aircraft.

It says ADS-B In reduces that buffer to less than 15 nautical miles, allowing pilots to utilize In-Trail Procedures (ITP), enabling an aircraft to safely move to a more optimum altitude thus reducing fuel costs, improving ride quality or both. In this way, more aircraft will be able to fly at the most optimum altitudes for overall fuel savings.

Honeywell says it has ADS-B Out solutions for the 23+ aircraft types equipped with Honeywell cockpits, but since each aircraft type has a different cockpit configurations, there is no-one-size-fits-all solution. It encourages operators to contact their local service center.

Garmin says it has ADS-B options for any budget or aircraft. The solution may be as simple as upgrading your Garmin GTX-330 transponder for $1,300 MSRP and/or installing an entry-level ADS-B in/out solution starting at $3,995 MSRP.

Garmin says there are a lot of things to take into account when planning your ADS-B installation — like your current aircraft configuration and what ADS-B benefits you’d like to take advantage of. It has a planning tool on its web site to get a detailed hardware recommendation based on your specific needs.

Jessica Koss, Garmin’s Aviation Media Relations Specialist, said: “From our perspective, aircraft owners are realizing the benefits and value-add of an ADS-B solution and the demand is steadily on the rise. This increase has caused a backlog in avionics and ADS-B installation quotes – sometimes several months out. Going forward, we expect the demand and installation backlog to continue to increase as we near the deadline.”

But are people opting for ADS-B “In” as well as “Out”?

“Many customers are electing to go beyond ADS-B Out and upgrade to receive the benefits of ADS-B In because the benefits are realized immediately,” Koss said.

“Subscription-free FIS-B weather in the US alongside traffic on a moving map with reference to flight plan information, significantly increases situational awareness in-flight and on the ground. With these tools, equipping to receive the benefits of ADS-B In is a simple and straightforward decision.”

Garmin says don’t wait and plan ahead. As demand and avionics shop backlogs continue to increase, aircraft owners may find it difficult to complete the installation in the timeframe they prefer.

Universal Avionics has joined forces with Rockwell Collins to bring an affordable ADS-B “Out” solution to aircraft operators. The incentive package program is designed to allow operators to combine the Rockwell Collins TDR-94(D) Mode S Transponder with Universal Avionics SBAS-FMS.

Universal is also a strong advocate for ADS-B “In” technology. It has prepared a white paper called “Understanding Compliance with Automatic Dependent Surveillance – Broadcast (ADS-B) Out” that explains the mandates in detail.

Robert Randall, Universal Avionics’ Senior Sales Manager, United States, said: “There has been a significant increase in operators upgrading to ADS-B Out as they are realizing that there are a large number of aircraft that must comply, and suppliers and install facilities may become very busy as time moves closer to the deadlines.

”Some MRO facilities are taking reserved slot orders with low deposits in place to hold these slots for upgrades.

“To help our customers economically perform the required SBAS upgrade, Universal has several incentive programmes with our FMS, including a package programme with the Rockwell Collins TDR-94D transponders. These seem to be helping customers budget the upgrades more cost effectively.”

Universal Avionics advises customers to really study and understand their aircraft operating requirements, not only for ADS-B, but also for RNP and CPDLC operations that are also on the FAA’s NextGen roadmap.

“For some of these future operational and current operational requirements a ‘stand-alone GPS and transponder system’ may seem enticing and cost-effective, but may lead to additional costs later on,” Randall said.

Universal said it would also encourage operators to evaluate the incentives the FAA is offering for ADS-B upgrades as well as the continued tax incentives approved by the US congress for “Bonus Depreciation Expensing Allowances” that could allow a business to take credit for up to 50 percent of the cost of any aircraft modifications including labor.

The FAA has a $500 ADS-B incentive, but it applies to single engine piston aircraft. Companies are also offering deals on ADS-B upgrades.

ADS-B will soon no longer be restricted to line of sight. Aireon is deploying a global, space-based air traffic surveillance system for Automatic Dependent Surveillance-Broadcast (ADS-B) equipped aircraft over the entire globe.

In 2018, Aireon says it will provide the first global air traffic surveillance system using a space-based ADS-B network that makes it possible to extend visibility across the entire planet. Aireon is working with Iridium to place ADS-B receivers on 66 of its Iridium NEXT satellites, with six in-orbit spares and nine ground spares.

Iridium Communications announced the successful launch of its first 10 Iridium NEXT satellites, with Aireon ADS-B receivers, into low-Earth orbit in January. Aireon told me its receivers can pick up any aircraft with a top-mount ADS-B Out antenna that’s transmitting on 1090MHz, so that can include business aircraft. It added it is starting to run flight trials on 125 Watt systems in March 2017 and will have better data once those are completed.