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Living Room Connectivity at 24,000 ft


High-speed broadband is pretty much a standard feature in every living room or office, but until lately, not so much in the cabin of an airliner. Honeywell Aerospace demonstrated its solution to that problem to a handful of journalists onboard the company’s Boeing 757 engineering test bed on June 9.

The solution involves Inmarsat’s Ka-band broadband service, called GX Aviation, and Honeywell’s receiving equipment (the antenna and associated electronics), known as JetWave. Lufthansa was an early adopter of the JetWave equipment and GX service starting last year (click here for a video of an installation). Others, like AirAsia, are following.

So why all the buzz? Take a flight using legacy satellite or early air-to-ground equipment and you’ll realize in a hurry. Having access to speed and secure data will also play a role in the evolution of the cockpit and how pilots and airlines operate.

I flew on American Airlines from DCA to LGA to sample Honeywell’s wares, testing my connectivity capability with an iPhone on every leg of the trip.

The AT&T LTE wireless link at the gate at Reagan National delivered a speedy 36.84 Mbps download (data into my phone) and 6.99 Mbps upload with a delay of 32 milliseconds. However the Gogo air-to-ground link on my American Airlines Embraer E190 flying at 23,000 ft. to LGA yielded 0.45 Mbps download and 0.29 Mbps upload at a price of $9.95. Advertising in the in-flight magazine was specific – NO STREAMING ALLOWED.

How much bandwidth is necessary for a true living room experience? The general consensus for minimum bandwidth for streaming data to applications like Netflix or Apple Music is about 1 Mbps. Inmarsat’s I-5 satellites, which provide the backbone for GX, have a theoretical maximum of 50 Mbps for each Ka-band receiver that hooks up. I personally operated four devices simultaneously with bandwidth-hogging applications during our demo ride on the 757, with no noticeable delays, but more on that later.

Honeywell builds the hardware that taps into and distributes that data onboard. On the crown of the aircraft is the Ka-band steerable antenna (see picture below - looking down from above, without the dome), which rotates 0-90 degrees around one axis and 360 degrees around the other, making it be able to point anywhere in the hemisphere above the aircraft.

Mounted below the antenna and also under the dome are two receivers (allowing Honeywell to track two I-5 spot beams simultaneously in areas where the beams overlap, always staying connected) and a power amplifier with up-converter and down-converter. In the northeastern U.S., where we were flying, aircraft can quickly cross into a neighboring spot beam; whereas farther out west, a flight might stay within one beam. The first picture below shows all the spot beams; the second our position as we started to cross into a new beam.

The up- and down-inverters are fairly ingenious. Rather than keep the signals that come to and from the antenna in the Ka band, Honeywell converts to the L-band for the in-aircraft portion of the system to greatly simplify the wiring.

“We don’t have to worry about a long wave guide pipe that’s hard to work with,” says Stephen Klander, a Honeywell senior manager in project engineering, of the equipment that would be needed to keep the signal in the Ka band throughout the aircraft. “We use standard coax (coaxial cable) until we get outside the aircraft.” He says there are some losses in signal strength due to the conversion, but post-installation Honeywell has a calibration feature that optimizes the system based on the cable lengths.

Klander was operating the monitoring equipment at a control station in the rear of the 757.

Inside the aircraft (in a test rack in this case) where four small line replaceable units (LRUs) on the bottom shelf (see picture below) – a modem manager and a network switch that are typically mounted in the avionics bay; an electronics box for steering the antenna, and a memory device that Honeywell calls the “aircraft personality module.”

And the final link, as it were, to us the “passengers”, was a single Linksys router. Klander says a smaller business jet might only need one router whereas an A380 would likely have multiple routers. “You have to do a survey to understand where you have good connections,” he says.

With 33 devices hooked up among all the journos on board, I was able to do pretty much anything I wanted. I had four devices myself – the iPhone, a droid phone, an iPad and an iPad mini.

Streaming video from Netflix and Apple music worked perfectly. I did not try uploading or downloading large files (some early testers of GX have complained about this), but I did have a bit of trouble trying to update all 31 applications on my iPad. After about an hour in the air, I had updated most of the apps, but I had to hit the “try again” button several times. Below is a table of connectivity I achieved on various legs of the trip. 

A fellow Aviation Week reporter, Mike Lavitt, had taken a ride on Gogo’s 737 in May to test out the company’s new 2Ku service through Intelsat’s new Epic series geostationary satellites. He was able to get 33 Mbps download rate, but in a test of his virtual private network link became disconnected.

Except for the somewhat slow update to the apps, my connectivity experience was truly the same as it would have been at home with my Verizon Fios.

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