Why do Fountain Pens Leak at Higher Altitudes?

There’s a popular misconception that fountain pens and aircraft simply do not get along. Whilst fountain pens (and indeed most rollerballs) are more prone to misbehaving in a pressured environment, there are some painless steps you can take to minimise the likelihood of that crisp, white shirt looking like an artist’s smock when you walk through the arrivals terminal. Before we get to that, let’s look at the science behind it.

Why does it happen?

Typically, passenger airliners fly at an altitude approaching 40,000 feet. At this height the air is so severely lacking in oxygen that if you were to breathe it normally, you would have approximately 12 seconds until you start suffering from disorientation and losing consciousness which will ultimately result in death. In a pen’s case, air will expand or contract depending on the change in pressure. The cabin pressure of an aircraft at this height is the equivalent of being at 7,500 feet which has quite a severe impact on the inside of your pen as it will still have the same pressure it did at ground level. The result? A large collection of ink will gather near nib/feed section of the pen whilst the expanding air will push the ink out.

Tips for avoiding leakage:

  • This issue can almost always be avoided by ensuring your fountain pen is stored (either in your shirt pocket or in your bag) with the nib held up-right. This means that when the air inside the pen matches the air outside of the pen, the nib and feed area will have no issues with the air re-entering.
  • Ensure your fountain pen is completely empty (no ink to leak out) or completely full (no air trapped inside) when you’re travelling. Do not attempt to use your pen on your flight’s ascent or descent however, as this is almost certain to result in messy consequences.
  • Play it safe. Put your pens into a zip lock bag and carry them in your briefcase or carry-on. Keep your pocket pen in a cigar tube. And always keep your pocket pens nib up. You should be fine.


Recent solutions

Platinum, the Japanese pen brand recently released a fountain pen with revolutionary ‘Slip and Seal’ functionality. In short, this airtight mechanism reduces moisture evaporation, meaning that the pen can go for long periods of time without being used and the ink won’t dry out. The device will also protect against leakage brought on by changes in atmospheric pressure, but remember: keep it stored nib-side up with a full cartridge/piston or keep it completely empty!

7 thoughts on “Why do Fountain Pens Leak at Higher Altitudes?”

  • Brad
    Written by Brad on April 25, 2019

    I've noticed that it is only my long international cartridge pens that leak in the air. My short international cartridge pens are fine. I fly twice a month trans-pacific or trans-atlantic and it's only the long cartridges that cause me a headache. The long cartridges not only have softer sides, but of course more potential air space in them. The shorties are stiffer, and have less air space. Wish I could convert my pilot fountain pens to shorties!

    S. T. Dupont using Dupont or Diamine or just about any other cartridge. The longs are almost all Pilots using Pilot cartridges. The Pilots get a baggie for every flight now. And it doesn't matter if they're standing upright or not.

    I don't fly with converters, so no experience to relate on those.

  • Written by Geta on March 23, 2018

    Way cool! Some extremely valid points! I appreciate
    you penning this post and also the rest of the site is also really good.

  • Jasa
    Written by Jasa on January 20, 2018

    You're so cool! I don't believe I have read anything like that before.
    So good to find another person with a few unique thoughts on this topic.

    Really.. thank you for starting this up. This website is one thing that is required on the internet,
    someone with a bit of originality!

  • Ndawula Zacheus
    Written by Ndawula Zacheus on April 11, 2016

    so great!

  • Onam Bansal
    Written by Onam Bansal on March 9, 2016

    It is due to capillarity.

  • Cal Zimmer

    I've always thought that I had an unusual amount of leakage with some of my pens. It never even crossed my mind that it could be the altitude. Thanks mate!

  • Ernesto
    Written by Ernesto on June 8, 2014

    Very shortly this website will be famous amid all blogging and site-building users, due to it's good articles

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