Tech

Taking a flight on the best Boeing 757

Checking out Honeywell's airplane test bed, and Inmarsat's new satellite Internet service.

Sebastian Anthony – Jul 3, 2017 12:22 pm | 82

Credit: Sebastian Anthony

The 787 Dreamliner, with its composite-fibre chassis, lithium-ion batteries, and super-efficient engines, can fairly claim to be the coolest airplane in the world. Another reasonable choice, if you really revere giant flying tubes of aluminium, is the gloriously ginormous Airbus A380. And of course, true aerospace connoisseurs would probably choose the SR-71 Blackbird, or perhaps even the Concorde. But I can tell you now, all of these planes pale in comparison to the Boeing 757, built in 1982, that I just had the pleasure of flying in.

Externally this 757, which was only the fifth of its type to roll off Boeing's production line, looks fairly normal—until you spot a giant bracket on the side of the fuselage where an optional third engine can be mounted. That pylon isn't for redundancy or extra power, though: it's for field-testing new jet engines.

Stepping inside the airplane, which is owned by multinational conglomerate Honeywell, things get even cooler: to the left is an open cockpit with two softly-spoken American pilots, and to the right there are 10 ageing leather seats. And then, behind the seats... there's a 1980s-era science lab.

There is no plastic cladding, nor overhead bins. There's insulation, of course, so that you don't freeze to death, but in a few places you can see and touch the three millimetres of aluminium that make up the airplane's hull. There are the usual windows, and the space feels a lot lighter than a normal passenger jet. Miles of neatly ducted, shielded cables run along the ceiling. A big steel box on the floor contains the emergency oxygen supply. A number of large cabinets contain diagnostic equipment for the third engine mount (which sadly isn't equipped today).

Heading deeper into the aircraft there are a bunch of terminals: large metal enclosures that can be outfitted with whatever equipment is required for the flight. In front of each terminal is an engineer or technician who is poking around on a keyboard or fiddling with some switches; chunky switches that take me straight back to electronics class at school 25 years ago. I was on the plane to try out a specific technology, but most of the terminals were being used to test other Honeywell prototypes. It's mighty expensive to crew and fly a 757, after all—Honeywell wants to make the most of every flight.

After a while there aren't even any terminals: there's just empty space and random detritus on the ground, like a 24-pack of water bottles. The back wall is padded, presumably to stop any unstowed objects from crashing out of the tailplane. After taking a few selfies, I wander back up the aisle to check out the star of the show: Inmarsat's new Global Xpress satellite Internet service.

A map showing the current coverage of Inmarsat's Global Xpress satellite constellation.

Just outside the airplane, beneath a plastic fairing, is an arrow antenna that follows one of Inmarsat's four geostationary Global Xpress (aka I-5) satellites. The I-5 constellation consists of three satellites that provide almost unbroken global coverage, and a recently launched fourth satellite that provides extra coverage (i.e. bandwidth) over Asia. Each satellite produces 89 discrete Ka-band (20-30GHz) spot beams that users can latch onto. Spots have their own dedicated wedge of spectrum and bandwidth, to reduce interference and congestion.

A speedtest running on an engineer's laptop. Credit: Sebastian Anthony

As the 757 banks and turns, the antenna moves so that it always points at the satellite. If the airplane crosses from one coverage area into another (in the middle of the Pacific or Atlantic, for example), the antenna quickly whips over to a new set of coordinates. It still takes about 45 seconds to renegotiate a connection with the new satellite, though. (I asked an Inmarsat engineer why it takes that long; he wasn't sure, and suggested it was something they could probably improve on.)

In the case of GX Aviation (the name of the product used by aircraft to connect to the Global Xpress satellites) each end point has access to 50Mbps of downstream bandwidth and 1Mbps upload (sending data to a satellite is still really painful). In practice, as my plane buzzed by Colchester and headed towards Norwich, I got around 30Mbps, which is enough to stream Netflix or scroll through your video-infested Facebook feed. Latency was about 600ms: exactly what you'd expect when bouncing packets via a satellite 22,000 miles away. Facetime and Skype worked okay on my end—I saw a lovely, smooth image on my phone—but a friend, sitting in an office in London, definitely felt my limited upstream bandwidth: the image stopped and started, and I looked jpeggy.

A screenshot of the Honeywell weather app for pilots.

50Mbps is a massive improvement over other contemporaneous satellite Internet products, which range from about 300Kbps to 3Mbps. But if you tell 200 passengers that they can all stream Netflix while over the Atlantic... well, you can probably guess how that will go. You could restrict access to the local Wi-Fi network—perhaps only business-class passengers can stream Netflix—but only real solution is boosting the link speed between satellite and aircraft. An Inmarsat engineer says that downlink speeds of 300Mbps would be possible with a high-gain antenna, but they don't yet have the technology to whack a giant parabolic dish on top of an object hurtling through the air at 500mph.

20 airlines have signed up for GX Aviation so far, and Inmarsat says that 1,200 aircraft will soon be equipped with 50Mbps satellite Internet access. Honeywell, which manufactures just about every piece of aerospace equipment you can imagine, including the satcom terminals used by most planes in the sky today, avionics, and jet engines, has a vested interest in GX Aviation: they've just rolled out a bunch of new Internet-connected apps for pilots. There's a real-time weather app that helps the captain make strategic decisions to avoid turbulence, and Flight Bag, which lets flight crew plot more efficient courses, saving time, money, and fuel.

Inmarsat plans to launch a fifth Global Xpress satellite in the next few years—which will probably coincide with the first satellites of SpaceX's low-altitude constellation. Last week, an Ariane 5 rocket launched an S-band satellite that plays a key role in Inmarsat's high-speed European Aviation Network—which will offer 4G-like connectivity for aircraft, but only over European airspace. We'll have more on EAN at a later date.

Now read about that time I visited a 747 graveyard...

Sebastian Anthony Editor of Ars Technica UK

Sebastian is the editor of Ars Technica UK. He usually writes about low-level hardware, software, and transport, but it is emerging science and the future of technology that really get him excited.

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