There’s good news to report on the NextGen front: It’s progressing! That progress is measurable and visible in the expanding ground-support infrastructure for Automated Dependent Surveillance-Broadcast (ADS-B) and a continually lengthening list of Instrument Approach Procedures that build on the operational Wide Area Augmentation System (WAAS).

Dave Higdon  |  01st January 2011
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Dave Higdon
Dave Higdon

Dave Higdon is a highly respected, NBAA Gold Wing award-winning aviation journalist who has covered all...

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Getting To NextGen From Here:
ADS-B backbone takes steps forward... and some back too.

There’s good news to report on the NextGen front: It’s progressing! That progress is measurable and visible in the expanding ground-support infrastructure for Automated Dependent Surveillance-Broadcast (ADS-B) and a continually lengthening list of Instrument Approach Procedures that build on the operational Wide Area Augmentation System (WAAS).

In 2010 regulatory folks at the Federal Aviation Administration issued its final rules- mandating the installation of airborne ADS-B Out-compatible equipment- setting a long deadline for compliance – all the way out to 2020 – and verbally encouraging early adoption- based on the believable goal of completing the initial ground-based nationwide network by 2013.

We started seeing parts of the network go live- with ADS-B Out aircraft detected and tracked through a few operational regional networks of ground stations. A slow increase in ADS-B compatible airborne systems fed the enthusiasm that NextGen’s infrastructure and systems are coming together.

Less capable of generating any breathless enthusiasm is what that progress means- and how it may- or may not actually contribute to moving the United States forward toward NextGen (the Next Generation Air Traffic Management system).

So the sum of the situation stands as follows: just how much progress has been achieved is difficult to weigh beyond the updates on the support infrastructure…more stations- steady expansion- all on-track to finish on-schedule in two years. But in other areas of the ADS-B story- doubts are taking root.

The doubts span the spectrum of what NextGen promises - whether that be the operational benefits- the user adoption- or the efficiency gains likely (or unlikely- depending on your perspective). It can be easy to ignore promises of “new”- “improved- “faster”- “better”- and listen more to the doubters and skeptics.

Increasingly pilots and aircraft owners- avionics makers and shop owners question: What if you built a better ATC system – and nobody came?

Occasionally an advance comes along with such promise and potential that supporters gradually begin to extend that potential far beyond the original needs until it’s viewed as a ‘Nirvana for aviators’.

Imagine the potential: a piece of equipment that broadcasts position data accurate to within a few meters – in all three axis – while throwing in comparably accurate groundspeed- altitude change-rate and direction of flight for good measure. Controllers receiving this information benefit from its precision and accuracy- plus its frequency since the system updates itself a hundred times a minute.

Controllers aren’t the only recipients of this flight information- though. Every properly equipped aircraft within 150 miles of your airplane receives- and displays the same information on yours- and every other ADS-B Out airplane. And aircraft with the ADS-B In technology required to receive ADS-B Out broadcasts also benefit from other data- including graphical weather data (NexRad Radar images) and text weather data (METARs- TAFs- PiReps and NOTAMS).

Traffic and weather- through the ATClink - with no charge- and without individual sensors for the weather and traffic shown. What’s not to like?

That’s why the FAA has- for years- touted these benefits as reasons for pilots to invest in ADS-B for their aircraft. But that embrace didn’t include the FAA itself- which ignored ADS-B In equipment in its new rules- and has since left the future of those services – the main draw for pilots - up in the air. The FAA only started selling those benefits back in the 1990s.

While the enthusiasm generated by early progress was clear- the disappointment from the rules and subsequent actions has served to pull the brakes on that enthusiasm and feed a growing sense of doubt in the entire idea. These and other wounds in the promise of NextGen appear largely self-inflicted. Those wounds include:

• A wholly lopsided- unfulfilling equipment proposal;
• New installation-approval constraints;
• A total failure to embrace the aspect of ADS-B that could directly benefit pilots.

The high degree of accuracy- improved separation standards- more direct flights and improved runway acceptance rates should hold appeal to both the FAA and the commercial operators- alike- but the cost estimates have the airlines questioning the investment.

Furthermore- there’s a compounding effect in play. Business Aviation insiders - many long supportive of- and early adapters of NextGen-enabling technologies like GPS and WAAS - are also less enthusiastic than before the equipment rule was finalized.

Those wounds don’t include recent government audits that challenge whether the FAA is managing and spending properly for the project- or growing evidence that the FAA seems to know little about how it plans to make ADS-B work to produce a better air-traffic product capable of handling the growth driving NextGen.

The FAA’s new rules requiring ADS-B equipment for airspace access by 2020 covered only the so-called “Out” functions: equipment to broadcast the WAAS-GPS data for the FAA to process on to controllers’ screens. The system- if put on-line and working as promised- will give the FAA the higher accuracy and faster update rates needed to work with other technologies to increase airspace capacity.

With higher accuracy airplanes can be routed more closely to one another and at staggered altitudes with smaller divisions – and with the right computing power open up the national airspace to full free-flight- or GPS-direct routings. The FAA wants those benefits as quickly as possible.

But in light of the STC-approval requirement for new installations- the need to maintain the old transponder- and a general lack of direct benefits for the aircraft owner- airlines and private operators alike are digging in and beginning to push back.

The biggest mistake- FAA insiders concede- was in ignoring the ADS-B In technology – the side of the ADS-B coin that actually delivers information to the in-flight cockpit. Equipped for ADS-B In- the pilot can see traffic – both other ADS-B-equipped planes- and those coming through the ADS-B broadcast via a radar datalink. ADS-B In provides the link for nearly live datalink weather- METARs- TAFs- texts of NOTAMS - even lightning. But the FAA- aside for approving the TSO for such equipment- only alluded to the potential of those products- and hinted at possible rulemaking action on ADS-B In at a later date.

As one avionics company executive noted- “It’s not that I don’t appreciate the FAA trying to increase my business- it’s just that the owners absolutely do not like the idea of complying with the new ADS-B Out requirements only to have to do something different to stay in compliance and have ADS-B In. “Actually- scratch that-” he added. “I don’t appreciate them leaving out the main selling point of the whole thing – the service pilots can get. It’s keeping us from selling much of any ADS-B hardware right now.”

Yet that is not the only challenge facing ADS-B and NextGen. Other issues are in play- even as the need for NextGen continues to close in on the FAA.

FAA and industry forecasts predict that air traffic will double again in the next two decades. Absent substantially more runways- some of the growth can be absorbed with larger airliners flying more flights.

To keep all flights flowing to their destinations as quickly- and as directly as possible the FAA needs technology better able to track and manage those flights than today’s combination of ground-based radar triggering airborne transponders; accuracy alone precludes increasing traffic density.

ADS-B offers a level of accuracy unparalleled in transportation management – down to a tenth of a nautical mile en-route. The technology blends satellite-navigation-system-derived position data- corrected by an accuracy-enhancement system- with affirmative reporting of position- speed- altitude and flight vector – a hundred times a minute.

Compared to a technology that- at best- updates flight data a few times a minute- ADS-B delivers more- and with more accuracy – even at the highest speeds domestic traffic flies. We’re talking about equipment going online- on-schedule; OEMs with airborne systems… so what’s holding back the typically gadget-happy aviation community.

After what critics label recent missteps by the FAA- what the aviation community needs- ultimately- is some incentive to adopt. Right now the FAA is in the dubious position of trying to sell a program – one that will cost users billions – on the basis of the ‘someday-benefits’ indirectly promised from making ATC’s job easier and more accurate.

As it currently stands- as the users move to the new equipment- they’ll be required to continue carrying a piece of equipment they thought was headed to museum-piece status – the Mode C Transponder. In fact- some operations with ADS-B may even need two – even if one performs the both roles.

So- in a nutshell- ADS-B is (on its own) advancing largely as promised at the agency level- and should be nationally operational on-schedule. Whether equipment manufacturers have equipment legally approved for installation- however- operators may choose to sit out the change – at least early on.

The equipment specifications have been in place for about a year; but given some of the FAA’s less understandable actions- OEMs are understandably slowing their new-equipment development efforts in the hope that some of this will get sorted out.

In another threat to a happy change-over we must also note that faith in benefits expected to accrue to the early adopters will be sorely lacking. It’s happened before- of course: it happened with another promising system- one that could have vastly increased airspace capacity in over-saturated terminal areas… could have- but ultimately didn’t. The similarities could not be more striking.

The much-vaunted MLS proved its potential in some of the nation’s toughest landing environments. It broadcast a signal from a ground station that the on-board receiver used to provide position reporting and approach guidance. More accurate than ILS- MLS and the airborne receivers allowed for the creation and use of curving- three-dimensional approach control that could precisely lead a pilot to a runway threshold in conditions below the level entrusted to ILS.

If this idea sounds familiar today- take a look at Required Navigation Performance 0.1 – a system that provides a WAAS-equipped aircraft with the proper Flight Management System to fly curved- three-dimensional approaches with a degree of accuracy unavailable with radar- and impossible with the straight-line guidance of an ILS system.

Sadly- the FAA’s plans to embark on a widespread installation program – starting with airports like Aspen and Washington National ran headlong into multiple issues- some of them as much the fault of the community as the FAA. For example- its up-front costs and the uncertainty of its deployment stifled development of the cockpit systems needed to use the ground-based technology; that helped further drive up expected prices- reducing OEM interest.

Feeding the resistance were detractors who pointed out the potential of the then-infant idea of satellite-based navigation. They reasoned that investment should go full steam into satellites and not into what they considered a bridge system on the way to the space-based solution.

For those reasons – which would be another 20 years approaching maturity – the FAA and the community abandoned a here-and-now winner that would have had an impact. Despite the failure of MLS to catch on- the idea - the promise of MLS - resides in the promise of a technology that vastly improved landing accuracy and position info during approaches. It’s ADS-B that’s kept that idea alive and well.

Now here we are- nearly 30 years later- and the accuracy and flexibility in MLS is still held out as something GPS can do – and it can…now that we’ve added WAAS- multi-lateration- and ADS-B to the latest advances in GPS satellites and navigators.

ADS-B went on-line to controllers’ screens in several areas last year. The largest of those regions was the Gulf of Mexico- where about 3-800 platforms daily produce nearly 8 million cubic feet of natural gas- and in excess of 1.5 million barrels of crude oil.

Daily approximately 2-000 helicopters fly about 7-500 missions moving supplies- equipment- fresh water- food and the thousands of workers who operate and maintain the production platforms working 24/7- 365. The energy-production industry- helicopter operators and the FAA collaborated in the installation of a network of ADS-B ground stations on producers’ platforms.

Twenty-three ADS-B stations- 35 Automated Weather Observation System stations- and a similar number of communications- relay stations went on-line in January 2010- allowing a huge increase in IFR traffic monitored and coordinated through Houston Center.

Ongoing as of this writing was the final push to finish installing- connecting and initializing the last of 320 ADS-B ground stations required for initial operational coverage. There are- however- two problems:

First- even as the FAA works on its ultimate plan to expand ground stations to more than 800- it doesn’t help ATC if the planes aren’t equipped. The FAA recently added complexity and cost for installing ADS-B equipment in the plane by changing policy to restrict such installations to equipment STC’d for the airplane and other equipment. Field approval has been working fine- according to the Aircraft Electronics Association- the lead in a group of Associations questioning the policy change- and insisting the change be rescinded.

Second- the FAA seems- according to a Government Accountability Office (GAO) report- to be having trouble with implementation and costs. NextGen officials reported that full fleet equipage by 2025 could increase ground and airborne costs from earlier estimates of $40 billion to $160 billion.

Delaying required full compliance until 2035 would lower total costs yet remain substantially higher than the earlier $40 billion estimate; getting costs down to $40 billion- the report said- can come with reductions in NextGen capabilities.

The combined impact of these missteps and missed estimates: A commercial and private aviation public questioning the costs- the impact and the need of ADS-B. You can read the GAO report online at the following link:


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