Air Travel and Power Supplies

[kevin_standlee]

Our flight from Japan to Portland went smoothly. We were in what some consider the best seats in the whole plane -- 1AB on an A330 -- which gave us plenty of room to lay out our stuff during the flight without getting in anyone else's way. (But being bulkhead seats, there was no stowage in front of us, which is a pain because you have to keep getting up to get stuff out of the overhead compartments.) The main problem is that the power supplies on the seats are too weak. They're only good for 75 watts, and both our computers' power supplies draw more than that. So when we tried to plug in the power supplies and turn on our computers, the seats failed. The airline crews told us, "Oh, you have to take the batteries out of your computers in order for it to work." Well, not only does that mean that you end up with a hole in the bottom of your computer, but that the slightest glitch in the aircraft's power supply and your computer dies.

And glitches do happen. On both the HNL-NRT flight (a 747) and the NRT-PDX flight (an A330), problems with the on-board entertainment system obliged them to do a "hard reboot" of the on-board entertainment system, which apparently runs the power to the seats as well. This takes roughly twenty minutes. On the A330, I was amused to see the reboot code running on the screen at the front of the cabin -- apparently it runs on Linux.

I had sufficient batteries -- four of them -- that I could have probably stayed up for the entire flight, but Lisa had only two, and the game she plays uses a lot of power because it wants to run the CD-ROM continuously. Had we networked the two machines together as planned, it would have been worse. So she shut her machine down after an hour or so and did what she could to pass the time. She then switched to the other battery for the last 90 minutes or so before the breakfast service.

I note in passing that the instructions in the in-flight magazine say that NWA's 757s have 200-watt power supplies, which is more appropriate for the demands from our computers. I reckon the power supplies on the 747/A330 are okay for running smaller devices like iPods and such, but not for most modern laptop computers.

Comments

[bovil.livejournal.com]

My travel power supply (cigarette lighter/airline adapter) only puts out 60 watts. The laptop detects this and disables charging (60 is plenty to run, but not enough to charge or to run other high-performance modes). Haven't tried the laptop using a standard charger/inverter set-up.

[daveon.livejournal.com]

I have no trouble with inseat power on 747s and 777s so there's more likely to be a specific loading problem on that configuration. Which airline was it again?

I'd say that depending on the inflight entertainment, they pretty much have to do a "hard reboot" of the system on about 75% of the trips I take long haul. When they were first putting these in back in the mid-90s there were huge debates in the industry press about their value. There was, and to a certain extent, still is a gulf between the operating efficiency and the number of passengers so that on any given flight you'll have at least 2-3 units completely down. They had to stop retro fitting them to certain older aircraft because of the impact on the electrical system, and, worse of all for the airlines, the equipment weighs in at around a tonne for a 300 seat configuration (split between the screens, hand controls, players and extra wiring).

I've not fathomed why the reboot takes so long, especially on the older video based systems, but I'm sure they have good reasons. I suspect there is an element of "power it down and leave it down until you're damn sure the memory is clean" then turn it on.

[kevin-standlee.livejournal.com]

Northwest Airlines, and that, by the way, is why I use the terminology "World Business Class." Northwest doesn't have three-class service on their transoceanic flights. Instead, they created a sort of in-between class that is nominally better than Business but not quite as good as First and branded it "World Business Class."

The crew on that NRT-PDX flight claimed that the problem was with just that particular aircraft -- with which they're apt to be more familiar if they work that route regularly -- but given that I had the same problem (twice) between Hawaii and Japan on the way out, it doesn't surprise me at all to hear that the problem is endemic.

[daveon.livejournal.com]

Ah... I must admit that I try avoid Northwest. Virgin have "Upper Class" which is meant to be between First and Business, but they also have Premium Economy which is more like US domestic first.

In true Scandanavian style SAS don't have a First either, they have Business, Premium and Economy. But they have inflight internet which apparently works reasonably well.

I've never had a problem with the systems on any of the Cathy Pacific A340(I think) that I've flown on, but I've used them so infrequently it's hardly surprising.

The BA systems are up and down all the time.