Inflight wifi connectivity providers market their services with big claims of capacity to passengers. Gogo advertises its 2Ku solution as delivering 15 megabits per second of capacity to passengers. Viasat says 12 megabits per second on its Ka-band solution. Inmarsat uses 15 Mbps as its marketing target. But those numbers are not for sustained data rates. Put another way, you can see those speeds from time to time, but the suppliers all have systems in place to limit performance over time.
So, what performance will the vendors really deliver??
Vendors and airlines often agree to limit consumption. This helps control costs and ensures fair access for all passengers to the scarce resource that is internet in the sky. How limited are the speeds? That varies by vendor and is often hard to find spelled out.
The Gogo numbers
Gogo lists the details in its Acceptable Use Policy on the inflight portal page. Depending on the plan purchased or even which airline you’re flying the speeds seen over time will almost certainly be lower than the megabits per second advertised or seen in the speed tests.
Gogo expects that user of this pass will typically experience download speeds of 3-15 Mbps for the first 60 MB downloaded within an hour… After the first 60 MB downloaded within an hour, Gogo expects that users of this pass will typically experience download speeds of 400-600 Kbps for the remainder of the hour.
Specifics on just what the speeds are and how much “fast” data passengers receive varies by plan and airline involved. Delta Air Lines and American Airlines promise 300 MB of high speed data on their streaming plans before the throttling kicks in, but only 60 MB if connecting through a promotion (e.g. T-Mobile) or a roaming partner. Alaska Airlines offers a lower total volume of high speed data on its 2Ku browsing plan but faster speeds than Delta and American once throttled. LATAM only offers 150 MB of high speed data on its “Browse +” plan, but the slower speeds remain above 1 Mbps with that service, roughly double the 600-900 Kbps throttled speeds on the US carriers.
Gogo is generally good about showing the specifics of capacity throttling on board. The Viasat/JetBlue Fly-Fi solution offers far fewer details.
JetBlue may prioritize, restrict or set limits (such as bandwidth allocations, or limits on types of content accessed or transferred) on your use of the Service. In times of high network usage, this may impact the functioning of high bandwidth applcations. Accordingly, content, file sharing, or multiplayer games requiring high bandwidth, and streaming audio and video are given a lower priority, and at times may be blocked or not work consistently… If your data use exceeds the data usage allowances for the level of connectivity you have selected JetBlue reserves the right to reduce your available bandwidth.
HD video streaming won’t work at these throttled levels that doesn’t mean other services are similarly limited. And even at the throttled speeds some video streaming typically does come through. Netflix claims at 250 Kbps streaming codec for 480p video is available, though enabling it with airlines requires a commercial cooperation agreement (or did when it was announced in late 2017).
Viasat also acknowledges that the 12Mbps number per user is a target for its SLAs and based on bursts of data, not sustained throughput. A relatively recent pitch to an airline suggested the 12 Mbps speed would be realized on 50% of the end-user requests and 3 Mbps for 90% of the time.
Inmarsat‘s GX solution promises top speeds of 15 Mbps for users, similar to Gogo’s 2Ku numbers. But, depending on the airline and plan chosen both the speed and services available will vary.
The FlyNet suite of offerings across short-haul flights on the Lufthansa Group of airlines delivers includes Message, Surf and Stream tiers of service. Those are capped at 150 Kbps, 600 Kbps and 15 Mbps, respectively. But the 15 Mbps rate is not truly guaranteed. In the fine print passengers are informed that downloading 50 MB of data within 5 minutes will cause the connection to be throttled down to 1 Mbps connection rates for the duration of the session. Inmarsat also acknowledges that a total of 50 Mbps is available within any one satellite beam and that capacity must be shared among all aircraft in the area.
Other Inmarsat GX airline partners have different standards applied to connections. Qatar Airways chose to limit video streaming for passengers during the free trial period of service on board, though paying passengers could access such content, for example.
Panasonic plays, too
Lufthansa’s FlyNet service on long-haul flights runs on the Panasonic Avionics network, delivering a different set of speeds than the short haul offerings. The Chat plan caps data at 64 Kbps, enough for text-based services but don’t try adding a photo to the messages. The Mail and Surf options come in two tiers. The base level offers 400 Kbps data rates and limits users to 500 MB of total data transfer. After that the speed is throttled down to 64 Kbps, just like the cheaper Chat plan users. With the Mail and Surf Plus package the 400 Kbps rate limit is removed, with passengers theoretically able to surf at up to 15 Mbps. A 1 GB total data transfer cap is applied to this package, after which users are throttled to 64 Kbps as well.
On United Airlines the PAC kit will also throttle connections. Much like the Viasat/JetBlue solution, however, there’s no detail on what it takes to trigger the performance reduction. In its Terms of Service the carrier simply states that, “Operating bandwidth is not guaranteed for any level of service purchased and is dependent on several factors including but not limited to the number of Internet users on the aircraft and the number of aircraft in the nearby area. Downloading of large amounts of data or content or streaming video content by any user may be throttled based on available bandwidth.”
In this context the term “available bandwidth” may be misleading. The aircraft still has bandwidth available but it is no longer being made available in that session. Passengers simply need to log out of their initial session and purchase a new one and the throttling is removed. Indeed, the issue is as much about paying for the data used as it is ensuring access to the shared connection for others on board.
Down, but not out
In most cases the throttled speeds remain sufficient for the desired/advertised content tier. A video can still stream at 600 Kbps or 1 Mbps, for example, though not in HD. For most web browsing the difference between 1 Mbps and 15 Mbps will similarly be a non-issue; overall page load times should appear rather similar, especially considering the latency in satellite-based connections.
So, sure, run that speed test on board to see the cool megabits numbers. But also keep in mind that there’s only a limited amount of high speed data available until the connection is throttled. And don’t get caught up on the advertised speed numbers from the vendors, because you’re unlikely to realize them long term.
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