I will be travelling on several long flights very soon. I want to use my laptop during the flight, in flight mode of course. Several flights have ports to charge devices. I have heard that the source often fluctuates during the course of the flight, and your device can get damaged as a result of this electrical fluctuation. Is it safe (for the laptop) to charge your device on such flights? Are there high chances of it getting damaged?

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    in flight mode of course; You don't have to except for the critical parts of the flight. You can use WiFi for the rest of your flight without any issues unless specifically advised not to do so, which is rare Commented Jun 14, 2017 at 8:05
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    @JamesBond - surely you can ask Q for a better laptop?
    – Mawg
    Commented Jun 14, 2017 at 14:31
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    Your question spawned another question with more details: aviation.stackexchange.com/questions/38934/…
    – Nav
    Commented Jun 15, 2017 at 14:23
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    @Mawg you don't know how hard it is for me to get a regular laptop. Q always gives me one with extra features like a self-destruct option - one wrong key press and boom.
    – James Bond
    Commented Jun 17, 2017 at 2:39
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    On a recent flight I had an USB port that triggered my device to show the option "Connect as a USB device" ;-)
    – user40521
    Commented Jun 26, 2017 at 14:19

7 Answers 7


Yes, it is safe.

You obviously know that at home you get a certain voltage (e.g. 220V), and on your laptop charger it says that it accepts only that specific voltage, so when you use your laptop at home you feel safe. But in reality there is a certain level of fluctuation even at your house and unless you are using a cheap quality charger, the charger itself is designed with this in mind. Plus, no airline would go that far as to add plug to all their seats and install an additional electricity transformer, just to fry all passenger devices once in a while.

S*it can always happen, obviously, but it can happen at home exactly like it can happen in flight.

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    As always: make sure to have backups :) Commented Jun 13, 2017 at 10:44
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    Most chargers are rated for something like 100-240 V, so they can handle some variation. Commented Jun 13, 2017 at 10:57
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    I think their priorities are more that your device doesn't fry their system.
    – simbabque
    Commented Jun 13, 2017 at 11:02
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    @simbabque they cannot care less about that, as airplanes do not use 220V which is on a totally separated circuit built into the plane just to power passengers devices. And on a different transformer, when not an entirely different generator.
    – motoDrizzt
    Commented Jun 13, 2017 at 11:07
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    I'll presume that "Yes, it is" refers to the first question "is it safe", and not to the second question "are there high chances of damage"... :)
    – FreeMan
    Commented Jun 13, 2017 at 12:49

If you're really that concerned, bring along a surge suppressor and plug that into the plane's outlet then plug your laptop into that. If there's a power spike, the suppressor will eat it, if there's a dip your laptop will stop charging for a moment.

However, think about all the regulations and development time (years and billions of {insert your currency here}) that go into getting an aircraft certified for commercial service. I would venture to say that the power coming out of a socket in a plane is going to be far more clean and steady than the power coming out of a socket in your house. In no way am I minimizing the threat of a house fire, but in a house fire, a few people may be injured or killed - in a plane fire a few hundred people may be injured or killed plus anyone on the ground who happens to be in the way.

TL;DR: I believe that what you've heard about fluctuations in aircraft electrical outlets is probably incorrect. That does sound like a good question to ask at Aviation.SE.

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    I felt that on-board power quality was a good question, so I did ask it a Aviation.SE. Turns out I was right - power quality on board is at least as good as what you'll get at home.
    – FreeMan
    Commented Jun 14, 2017 at 19:49

The most popular charging system on a plane is made by Em Power. The EmPower 110VAC + USB In-Seat Power Systems (IPS) converts the three-phase 115VAC, 400Hz aircraft power into 110VAC (200 Watts maximum) and standard USB power (7.5 Amps maximum). I am unable to find specifications on the tolerances of the output and the fail safe mechanisms of the IPS.

Running a device without a battery might be problematic since any power fluctuations could cause a power cycle (i.e., a computer to reboot) which can be bad. Laptops run on DC power and the transformer (power brick) provides a fair amount of protection to moderate power fluctuations (and the battery prevents power cycling).


From experience using various devices across 100's of flights, YES, it is perfectly save to use/charge devices using on board power supplies.

What I suspect you are referring to is the occasional announcement to discontinue using the outlets at specific times. I have heard:

  • Just before departure: This is because of the switch over from gate to aircraft power. It's no different from flipping a household breaker off/on which some devices are sensitive to.
  • Takeoff/landing: I don't think there's anything special about this electrically (never asked). I think (again, never asked) they just don't want wires and such dangling around in case of an emergency.

Just make sure you have the right plug. Most newer aircraft are equipped with either the multi-prong 120/220V combo, USB or both depending on the carrier.

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    Yes, at takeoff/landing all carry on luggage must be stowed to keep what little room there is between your seat cushion and the seat back in front of you clear so you can get out slightly more easily in case of an emergency. Things plugged in with cords scattered about in that area are a safety hazard.
    – FreeMan
    Commented Jun 13, 2017 at 18:05

It is extremely unlikely, and even if the voltage went wonky for some reason and exceeded the limits of the 'brick' it would more than likely only damage the brick and not the computer itself.

The so-and-so in front of you in economy is more likely to suddenly recline and crush your screen or any other number of possible disasters.

If you are paranoid and are heading away from familiar places, stick a spare power brick in your checked luggage. I tend to keep spares wherever I use my notebook computer for extended periods of time. They are not unreasonable cost-wise if you order them before you need them urgently.

Edit: Power brick (huge 330W one, most are much smaller!):

enter image description here

If you (like me) reside primarily in a 120V country, then your poor aging power brick will suddenly see 240V for the first time in a while when you go abroad- and the chances of a sudden failure are somewhat increased, so having a spare along may not be a bad idea. Security folks can get snarky in some places if you can't demonstrate your computer starting up and force you to leave the computer behind even if you were not depending on it (I saw this happen to a fellow traveler earlier this year in Addis Ababa airport even though the connection was entirely airside).

  • Spare what, power brick right? Or you mean spare computer or screen?
    – Xen2050
    Commented Jun 14, 2017 at 7:19
  • If you're referring to batteries, I wouldn't recommend sticking a Li-ion battery in your checked bags if you're flying to the USA
    – FreeMan
    Commented Jun 14, 2017 at 11:35
  • @FreeMan You might not have your laptop on your lap either if you're flying to the USA Commented Jun 14, 2017 at 12:37
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    @FreeMan Actually this is one thing I agree with 100%. You don't want Li-ion batteries in the hold, including large power banks. I have had to submit chemical analysis in order to transport product with batteries installed by air (in quantity of course). The Chinese have been refusing transport of big Li batteries even in the passenger compartment for a long time. The really crazy thing is forcing people to check batteries due to terrorism worries or maybe just to hassle foreign carriers (eg. Turkish air flights to the US). Unacceptable risk, IMHO. Commented Jun 14, 2017 at 12:59
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    @FreeMan Restrictions on Li-ion batteries in the hold have nothing whatsoever to do with terrorism. It's because they overheat and potentially catch fire when short-circuited or if they malfunction. This is a genuine danger that was implicated in the crashes of two cargo flights (UPS flight 6 and Asiana flight 991). Commented Jun 14, 2017 at 15:06

Airplanes rely on a principle known as "Faraday Cage". Basically, if lightning hits the plane, it has no direct way to reach the ground (there is no wire connecting the plane to the ground), so the charge simply doesn't even touch the plane's electronics inside it (and in turn the sockets inside the cabin).

Same thing if you are hit by lightning while in a car (just not as efficent, since the distance between you and the ground would be way less).

You should therefore not have to worry about voltage "fluctuations" too much, and as Tor Klingberg mentioned in a comment, notebook chargers are usually designed to withstand voltage variations typically from 100-110V up to 240-250V, so you should be ok.

Another thing which no one seems to have yet discussed on this forum is the pressure factor. You may have heard about batteries exploding on planes (especially Li-ion ones). That is very rare (it never occurred to me, and I take hundreds of flight each year, always charging my laptop on board).

However, if you are really worried, you can always "limit" your max charge on the battery temporarily. Most laptops nowadays have a function called "Conservation mode" which only charges the battery up to 55-60%, which is the best range to keep it at if you want it to last you.

Hope that cleared up the situation a bit.


I don't know what could happen on a plane that is worse than the spikes and dips you get from ordinary plugging/unplugging you do every day, but if your laptop has some special value beyond its dollar cost, there seems to be one (1) company that makes USB-USB surge protectors, for less than $22.

If you are carrying a laptop around an airport and bringing it through security, your risk of losing it to thieves (including security personnel), or just forgetting it, is a hundred times higher than the risk of frying the hard-drive by plugging it into a plane, so back up your data either way.

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