Plane & Pilot
Thursday, June 19, 2008

Making ADS-B Work

The technology looks promising, but there are still unanswered questions about its implementation

ADSWhen it comes to owners being told they must install expensive new equipment in their planes, it’s always better to offer them more carrot and less stick as an incentive. For now, the FAA’s proposed mandate on Automatic Dependent Surveillance-Broadcast (ADS-B) is looking like too much stick and too little carrot.
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Text weather, including METARs and TAFs, are available on the FIS-B page of the Garmin MX20.
Almost universally, the criticism was based neither on the timeline for ADS-B adoption nor on the overall concept, but instead on the FAA’s insistence on mandating ADS-B Out, a decision seen by many as primarily offering the FAA a way to lower the cost of providing ATC services, while requiring the owners of GA aircraft to shoulder the financial burden.

To better understand the widespread opposition to the mandate as currently written, a quick comparison of ADS-B Out and ADS-B In is in order. The GA pilot who has only ADS-B Out will see few, if any, benefits over those provided by the current Mode-C-transponder-equipped aircraft. Those with ADS-B In, which also will automatically include ADS-B Out, will have complete access to datalink weather information, including radar images, surface observations and forecasts, plus detailed traffic information. In other words, with ADS-B In, pilots will have useful tools that greatly enhance the safe conduct of flight. With just ADS-B Out, pilots will simply be allowed to do what they’re already doing, but will have to equip their aircraft with an expensive new box to maintain the status quo. As with the adoption of any new technology, for all parties concerned, it all comes down to cost versus benefits.

If you spend the time to wade through the NPRM, the FAA’s position seems to be simple. They’ll provide all services (ADS-B In and Out) and let owners choose which version to install, but with a critical provision. Under the mandate, by 2020, owners must install at least ADS-B Out in aircraft they plan to fly in controlled airspace (in essence, this includes the majority of GA aircraft). Organizations and individuals who have studied or already used full-featured ADS-B services argue that this mandate offers no new benefits for owners and penalizes them by requiring new equipment.

“The ADS-B proposal is a good starting point for deliberation on the implementation of this cornerstone for the NextGen [Air Transportation System],” wrote Andy Cebula, AOPA executive vice president of government affairs. “However, the proposal isn’t acceptable in its current form. The implementation plan offers little benefit to GA operators. The FAA’s contract for ADS-B services leaves GA wanting; incentives are needed for ADS-B equipage.”

The AEA weighed in similarly, “The AEA, in general, supports the requirement to adopt ADS-B. However, the AEA doesn’t support this proposed regulation. The FAA has failed to offer a proposal that’s cost-effective and safety-enhancing, or even a complete proposal,” said AEA President Paula Derks. “In addition, contrary to public law, the FAA is proposing a performance standard in this NPRM that isn’t available for the public to review.”

The ADS-B traffic display as seen overlaid on the moving map of a Garmin MX20 MFD. Shown here is a high concentration of traffic over Hartsfield-Jackson International Airport in Atlanta, Ga.
Doug Macnair, EAA vice president of government relations, commented, “Most of the benefits cited in this NPRM either don’t apply to GA at all or are derived from technologies already being embraced and fielded by GA pilots and aircraft owners on their own, such as moving map and GPS. The FAA didn’t consult with the GA industry in developing this implementation proposal, and it shows. Under this proposal, the agency is dramatically shifting the costs of the National Airspace System from FAA ownership and operation of ground-based ATC surveillance technologies to the individual aircraft owner—to the tune of many billions of dollars.”

Again, it all comes down to money. As the plan is currently written, owners will have the choice to pay a smaller amount to satisfy the requirements of the ADS-B Out mandate, or pay for a more expensive installation that will provide them with full weather and traffic information. At this time, it’s difficult to accurately project the cost for either option based on current equipment availability. But that may change very soon.

Beginning with Capstone, the avionics box at the heart of ADS-B has been manufactured by Garmin. It’s designed to handle both ADS-B In and Out signals and is called the GDL 90 UAT (Universal Access Transceiver). So far, it has been manufactured in such limited numbers that it’s very expensive, and coupled with the need for a Garmin display unit such as the GMX 200 MFD, the total installation cost has approached $20,000.


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