Article by Greg Lindsay
Fast Company  |  May 2009

Honeywell’s GPS-based Landing Tech Could Save Airlines Billions

The first salvo against interminable flight delays is Honeywell's new GPS-based landing technology. It could also save billions for the airlines.


In January, passengers aboard Qantas Airways’ Airbus A380 flagship, the Nancy-Bird Walton, were taken on a slight detour during their final approach to Sydney. The plane swooped by the funeral of the actual Nancy-Bird Walton, Australia’s answer to Amelia Earhart. The plane’s sheer size might have shocked her, but she could have taken the stick and landed safely—the technology hasn’t changed much since the 1930s.

The pilots decided to honor her passing with an aviation first: turning off their ancient instruments and switching on a GPS-guided, all-digital system. Using satellites to continuously calculate its speed, altitude, and proper approach, the hulking plane nimbly touched down only inches off the centerline, the first GPS-powered landing by an A380. “I’ve heard other pilots say this is as great a leap forward as the jet engine, which I thought was a bit of an overstatement,” says Captain Alex Passerini, who was on the flight deck that day. “But this is certainly more exciting.”

As it turns out, putting a GPS receiver on a plane is easy, but correcting for its margin of error—as much as 30 feet for a rapidly descending airliner—isn’t. For that, pilots need an assist from the ground. Enter Honeywell Aerospace, an arm of the $37 billion industrial conglomerate, which has supplied Qantas and a growing list of airports and airlines with the only available ground-based augmentation system (GBAS) for GPS-enabled navigation.

GBAS, which Honeywell calls SmartPath, is the first piece in a much vaster plan to overhaul air-traffic control. (To learn how GBAS works, see the next page.) The entire next-generation system, prosaically dubbed NextGen, is 15 years behind schedule, and another 15 years out, with a $15 billion price tag. One expensive long-term alternative is to build more runways: Chicago’s O’Hare, for example, will spend $13 billion and 20 years realigning and adding runways to increase the number of takeoffs and landings by 20%. GBAS is ready to produce these kinds of efficiency improvements today—for pennies on the dollar. It’s an ideal example of the good that a seemingly insignificant “shovel ready” project can do.

The airlines just might be able to save themselves if GBAS can save them a little time. Aviation consultant Michael Boyd estimates U.S. airlines waste $9 billion a year on delays beyond their control—more than the combined losses of all the world’s airlines in 2008. Relieving congestion in the most crowded hubs (35 airports handle 80% of domestic flights) could be all that stands between the airlines and profitability. Not to mention between a safe and pleasant flight and terminal hell. “We’re trying to help the airlines fly better and really synchronize their operations into and out of congested airports,” says Honeywell Aerospace president and CEO Rob Gillette.

SmartPath awaits imminent certification from the FAA. The stakes for Honeywell are huge. Setting a de facto industry standard, it has a two-year head start on its competitors to switch every large airport in the world over from the current radar-based instrument-landing system (ILS) to its system. It pegs the existing market at 2,178 airports worldwide. (Hundreds more are being built in China and India.) It expects SmartPath to be up and running at 600 airports by 2020 at a base price of $2.5 million apiece, producing $1.5 billion in revenue.

GBAS will ripple through the air-traffic system. “The numbers can get really big really fast,” says T.K. Kallenbach, VP of marketing and product management for Honeywell Aerospace. It offers airports and pilots 26 separate approaches, as opposed to the one glide path in use now. Some will allow for fuel-saving continuous descents instead of stair-step approaches; others can keep the noise down by weaving around residential neighborhoods. GBAS will even make a difference on the ground, as taxiing planes can stick close to the end of the runway, saving minutes that compound over the course of a day. Most important, planes can fly closer together in all types of weather, making vastly more efficient use of the sky.

Honeywell and Continental Airlines are testing just how much the system can alleviate delays in the most daunting petri dish: Newark Liberty, the most congested airport in the country for four of the past six years. During rush hour at Newark—say, 6:30 on a Friday night—GBAS might yield at least a 25% improvement. Continental hopes that by landing four additional flights per hour during poor weather, it can slash ground delays in half, reducing the teeth-grinding time spent waiting at the gate by 45 minutes.

“Suddenly Continental no longer has congestion there, or in Houston, or any of its other hubs,” Kallenbach says. “It’s actually the second-order effects that deliver all of the big savings.” Maybe the biggest is the reduction in fuel costs caused by delays (along with a shrinking carbon footprint), because planes will no longer get stuck burning fuel while waiting for clearance to take off and land. “The benefits are there,” Gillette says. “People should have been doing this already.”

Inside the Next-Gen GPS-based Airplane Landing System

1. Plane Plane Go

GBAS receives microwave signals from 4 to 13 GPS satellites. “The most difficult thing isn’t determining the plane’s GPS position, but ensuring SmartPath doesn’t cause any errors,” says Honeywell’s T.K. Kallenbach, who has refined the system so that the chance of receiving erroneous data from even one satellite is essentially less than one in 10 million.

2. Meter Maids

The heart of GBAS is the four GPS antennae mounted around the airport. Unlike radar, they aren’t prone to interference and can be placed almost anywhere. The raw feed is accurate within 10 meters. The finished product—data for every plane in a 23-mile radius are collected, compared, contrasted, and harmonized by proprietary algorithms—is precise within 1 meter.

3. The Big Broadcast

Using these corrected coordinates, a VHF antenna broadcasts approach paths to the planes. These are passed to an onboard multimode receiver.

4. In the black box

The onboard multimode receiver, a black box, parses ILS radar, GBAS data, and the plane’s own GPS. “Imagine that it knows where you are and it’s talking to the ground, which explains where it wants you to go,” Kallenbach says. “One continually updates the other.” The raw data are rendered in a pilot-friendly interface, and the pilot isn’t likely to notice many differences between GBAS and the instrument landings she is used to. Training to land with GBAS doesn’t require much time in the simulator.

5. A Different Approach

The approach path is logged by the captain upon filing her flight plan. GBAS recognizes this and digitally broadcasts 26 separate paths to incoming planes and guides them in (ILS radios one). Some save fuel, while others reduce noise by weaving around neighborhoods. Smaller planes will be able to coast over the “wake turbulence” caused by engines ahead of them and land on shorter stretches of runway. The savings add up quickly.

6. Extending the Runway

The advantages of GBAS become more visible when the runway is not. With ILS, air-traffic control spaces planes more widely to account for its imprecision. Taxiing planes must also scoot back from the end of the runway to avoid interfering with radio beams. Honeywell estimates airports lose up to 25% of capacity during bad weather. GBAS renders moot all these causes for delays.

About Greg Lindsay

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Greg Lindsay is a generalist, urbanist, futurist, and speaker. He is a 2022-2023 urban tech fellow at Cornell Tech’s Jacobs Institute, where he leads The Metaverse Metropolis — a new initiative exploring the implications of augmented reality at urban scale. He is also a senior fellow of MIT’s Future Urban Collectives Lab, a senior advisor to Climate Alpha, and a non-resident senior fellow of the Atlantic Council’s Scowcroft Strategy Initiative.

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