Avionics: ADS-B strategies emerge

Should you be an early adopter?

August 1, 2013

Not long after the FAA took a giant step toward Next Generation Air Transportation System (NextGen) implementation in late May 2010, when it issued a final rule requiring many aircraft to equip with ADS-B Out capability by 2020, we said the smart move was to do nothing right away (“Next Step Toward NextGen,” August 2010 AOPA Pilot). Since then the avionics industry has responded with a variety of new and updated products, at a range of prices—and while more options undoubtedly are in the pipeline, pilots who know what they want can equip now, and begin to benefit immediately from in-cockpit traffic and subscription-free weather.

Another benefit to equipping early is that by avoiding the rush to avionics shops that will be inevitable as the January 1, 2020, deadline approaches, you’ll have more control over scheduling and aircraft downtime. Also, pilots who operate internationally need to keep in mind that ADS-B Out deadlines could be even earlier in some other countries. Any aircraft owner who has been through an avionics upgrade knows the process is not quick, and procrastinators could find themselves temporarily grounded in 2020 if the ADS-B Out deadline is not extended.

A utomatic Dependent Surveillance-Broadcast is one of the primary technologies supporting NextGen, which will shift ATC’s reliance from ground-based radar to satellite-derived position as the basis for aircraft separation and control.

Why? The radar infrastructure is getting old—and it can take as long as 12 seconds to update an aircraft’s position. ADS-B updates aircraft position more frequently—once per second—and is based on WAAS GPS position information, so the more accurate position information will allow ATC to reduce separation minimums.

You’ll need to have approved equipment. Current portable ADS-B receivers provide incredible situational awareness in the cockpit, but they will not fulfill the FAA’s January 1, 2020, compliance mandate.

There are two approved datalink options; the best solution for you depends on where you’ll fly—and there are reasons why you might want to consider using both channels (more on that later). The Universal Access Transceiver, or UAT, transmits on 978 MHz—and also allows you to receive subscription-free weather information in the cockpit, as well as TIS-B traffic information. The other method transmits on 1090 MHz, using a Mode S Extended Squitter transponder (ES for short, referring to the additional information appended to the Mode S transponder data). The 1090 ES datalink does not support reception of weather and TIS-B traffic information. Wait, you may ask—isn’t a transponder redundant in the brave new world of ADS-B? Not yet—transponders (either Mode C or Mode S) still will be required equipment after the deadline.

While there’s a lot of talk about datalink, it’s not the only requirement to play in the ADS-B game. Key is an approved position source—this means an FAA-approved WAAS GPS receiver. Many GPS receivers on the market today meet this requirement, and you may be using a GPS that can be upgraded, like the Garmin GNS 430 or 530; check with the manufacturer or your avionics shop. If you fly IFR and have not upgraded to WAAS, the move will allow you to fly LPV approaches—GPS approaches with localizer-like precision and vertical guidance that can allow you to descend as low as 200 feet above the runway.

You’ll also need an appropriate display for ADS-B In weather and traffic information. Because ADS-B In is not required by the FAA, you may be able to use an Apple iPad or another portable device to view this data.

In order to continue flying anywhere that a Mode C transponder is required today, you’ll need to equip with ADS-B Out. So, to operate in Class A, B, or C airspace; within the 30-nm Mode C ring around a Class B primary airport; most Class E airspace at or above 10,000 feet msl—or in certain airspace above the Gulf of Mexico—on or after January 1, 2020, you must have an approved ADS-B Out broadcast solution.

Strategies for equipping with ADS-B Out are emerging based on where you want to fly, whether you want to receive the weather and traffic information broadcasts—and how much you want to spend.

For some pilots, the choice in ADS-B Out transmitters has already been made. For example, if you fly in Class A airspace (above 18,000 feet) or internationally, a 1090 MHz datalink transmitter will be required. That could mean a Mode S transponder, like the Garmin GTX 330ES or GTS 33ES, or the GTX 23ES for Experimental aircraft—or the FreeFlight Systems FDL 1090 TX.

Most other pilots can choose between a Mode S transponder and a UAT, like the FreeFlight Systems Rangr or the Garmin GDL 88. UATs generally are less expensive than a Mode S transponder, but don’t make a decision based only on equipment cost—be sure to consider installation costs, including antennas, as well.

Some pilots may prefer a solution that includes both Mode S and UAT capabilities. Why might you want to do that? The Mode S datalink does not provide an uplink of subscription-free weather and TIS-B traffic data, so if you’re required to broadcast your position using Mode S, you’ll need the dual datalink to receive that information. You may not need to install an extra box to do this, however; you can opt for a dual datalink transceiver, like a version of the Garmin GDL 88 that receives ADS-B In on both the 978 and 1090 MHz frequencies.

Other products are emerging that could help to streamline your ADS-B installation. For example, if you need both an approved WAAS position source and a UAT transceiver—perhaps you have a GPS that cannot be upgraded to WAAS—Garmin offers a version of the GDL 88 with a WAAS GPS receiver built in. For pilots who don’t need the 1090 MHz capability, something like the GDL 88 with a built-in WAAS GPS receiver could be the simplest solution. FreeFlight Systems is working to obtain additional STC approvals for its 1090 MHz extended squitter transponder, which can incorporate a WAAS GPS. Other multifunction boxes are in development.

There are ADS-B-equipped aircraft currently in the fleet that do not meet the FAA’s ADS-B requirements—for example, aircraft used to demonstrate the technology in the Capstone program in Alaska, and others using the same ADS-B technology. Be aware of this if you buy an ADS-B-equipped aircraft between now and the January 1, 2020, deadline. Some older equipment is said to be updatable—the process could be as simple as a software update—but others could require hardware modifications or other changes. Check with the equipment manufacturer or your avionics shop, if necessary.

Also, the continuing financial impact of the federal sequester could cause portions of the NextGen timetable to slip. In early June, FAA Administrator Michael Huerta told the NextGen Advisory Committee that capital funding for contracts that will enable new capabilities should not be affected by the sequester—but budget flexibility authorized by Congress that has allowed related development work to continue will expire at the end of the fiscal year on September 30.

Whether you decide to become an early adopter or choose to wait a little longer, ADS-B implementation is a subject all aircraft owners will want to watch.

Email the author at mike.collins@aopa.org

The price is right

ADS-B is free--more or less

By Ian J. Twombly

Pilots are a notoriously cheap bunch. And for good reason. When fuel ticks more than $6 a gallon, it’s time to pinch pennies elsewhere. Sorry, kids, daddy needs to put gas in the airplane.

Lucky for us, there is one aviation service that is infinitely useful and pretty much free. ADS-B weather is available now for the most populated sections of the country, and is expected to be available nationwide by the end of the year.

It’s a refreshingly simple concept. Ground stations transmit the data. You buy a receiver and a display mechanism. You get weather. Lots of weather.

There are two radar products, Metars, TAFs, pireps, airmets, sigmets, convective sigmets, winds and temperatures aloft, special-use airspace status, and TFRs. For all that there are no contracts. No accounts or passwords. No credit card on file. No activation procedure. It’s the easiest thing since “Rinse, lather, repeat.”

Did I mention it’s free?

Given the open-source nature of the broadcast signal, there are dozens of ways to display ADS-B in the cockpit, ranging from an iPad to a top-end multifunction display. If you already have a tablet, you can simply take your pick of any number of receivers, and you have weather. These are now about $699 and up, and there are around half a dozen to choose from. Most are cheaper than the various XM options. As the capability expands, so too will the equipment options. And it’s likely prices will come down as well.

Which speaks to one of the main reasons to go ADS-B. It is the weather source of the future. Some day we will all be flying around on our own with controllers only giving us basic traffic avoidance guidance. Even that will be secondary to the traffic displays we will all have in our cockpits, thanks to Nextgen and ADS-B. By 2020 we will all need to be broadcasting our position via approved equipment (ADS-B Out), so we might as well benefit from the weather and traffic information that’s given back to us, even now. It’s like future-proofing your airplane and getting a nice parting gift of free weather as a thank you.

I say free, but of course you’re already paying for it with taxes. Best to take advantage of that investment and not waste a buck. It’s in your pilot DNA.

Email ian.twombly@aopa.org

ADS-B abomination

Anything but free

By Dave Hirschman

If you think ADS-B is free, I’ve got news for you. We’re all paying for it. The system is needlessly complex and costly, and ADS-B weather (known as FIS-B) is a step down from XM Satellite Weather products that have long been commercially available.

XM’s main benefit is that it comes straight from satellites so pilots can receive it on the ground before takeoff. If there’s a thunderstorm or heavy precipitation embedded in the clouds beyond the departure end of the runway, they show up on the screen before you fly into them. That’s not necessarily so with FIS-B which transmits from ground stations and in most locations requires climbing to altitude for signal coverage. XM graphics also are more detailed and current.

ADS-B traffic, or TIS-B, is a fantastic safety enhancement that, once again, we’re all paying for. The FAA goes to a lot of trouble to block this signal to aircraft that aren’t broadcasting ADS-B “Out” signals. Denying this potentially lifesaving information is a strong-arm tactic meant to induce aircraft owners to install ADS-B Out by the FAA’s 2020 deadline. The FAA has so bungled this process that there aren’t enough avionics technicians and approved products to equip every GA airplane in time. The deadline will certainly slip, just like virtually every other misbegotten milestone in this glacial process.

ADS-B is a fantastic concept that the FAA’s pioneering Capstone project in Alaska proved in the 1990s. A commonsense approach would have delivered it nationwide a long time ago and made U.S. standards compatible with international ones. (Raytheon proposed giving an XM Weather subscription to every pilot in the country and adopting a single, international standard—a simple solution that would have avoided today’s dual-channel abomination and ground network.) I have ADS-B Out in my own airplane and see traffic and weather on a tablet computer. The situational awareness is extraordinary. If the FAA dropped its foolish and self-defeating signal blocking gambit—at least until the eventual equipage deadline— pilots could see how wonderful flying with real-time traffic and weather really is, and they would voluntarily adopt it (just as pilots who see value in WAAS GPS receivers have already done).

Instead, the aviation bureaucracies have run amok, and we’re stuck with a bloated, cumbersome system that costs billions of dollars more than it should and is many years behind schedule. If that’s your idea of a bargain, I’d hate to see a bad deal.

Email dave.hirschman@aopa.org