<p>There are flexible ink receptacles for fountain pens known as <strong>ink sacs</strong> or bladders, like these:</p>
<p><a href="https://i.sstatic.net/2tNnt.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/2tNnt.jpg" alt="enter image description here" /></a><br />
<sup><a href="https://www.youtube.com/watch?v=Sjjnxz_lrBU" rel="nofollow noreferrer">source</a></sup></p>
<p>However, <strong>they apparently don't give any advantage over rigid cartridges</strong> when it comes to air travel (<a href="http://www.fountainpennetwork.com/forum/topic/325676-how-do-parker-51s-do-with-air-travel/#entry3891145" rel="nofollow noreferrer">here</a>: &quot;<em>sacked pens also have trouble with rapid pressure changes</em>&quot;, which is understandable as the material is quite rigid).</p>
<p>What you can do, is to <strong>always point the nib upward</strong>, as any air in the cartridge or sac will expand during cabin pressure adjustments and will force the (negligibly influenced) ink out of the nib. Having the nib topside will minimize potential flow.<br />
This is also why <strong>having the cartridge completely full</strong> (that is, without any air inside) causes the least leakage problems.<br />
After having used it (and before descending) you can always take out the cartridge and place it in a sealable container or bag.</p>

CC BY-SA 4.0
2020-08-13T12:30:58.727Z
2020-08-13T12:30:58.727Z
Joachim
<p>If boarding with it completely full prevents leaks in storage, that's because there's no bubble of air at ground pressure in the ink. That means you should be able to use it without a problem.</p>

CC BY-SA 4.0
2020-08-13T11:14:42.530Z
2020-08-13T11:14:42.530Z
Chris H
<p>There are things you can do to reduce the risks, as described in the other answers, but I would be wary of using any kind of pen containing liquid ink on a plane (although a &quot;felt or fiber tipped&quot; pen may be OK; never investigated that).  I've had a Pilot Precise technical-style pen that uses disposable refills (the entire guts of the pen), leak while sealed in the tip-up position.</p>
<p>If you need to write on a plane, pens with gel ink (which also includes most ballpoint pens), are much less likely to leak.  The best type would be a Fisher &quot;Space Pen&quot; (various other pens can also use those refills).  These are manufactured pressurized and are designed to use that pressure to feed a very thick ink without leaking (they can write in the vacuum of space without leaking).  If writing with a fountain pen is important, I would just wait until you land to do it.</p>

CC BY-SA 4.0
2020-08-13T21:11:51.813Z
2020-08-13T21:11:51.813Z
fixer1234
<p>When a fountain pen is onboard an aircraft, it can leak ink due to the strong pressure difference inside the pen vs. outside the pen. This can result in messes to clean up on the flight even if the pen is not used, and at best ink blots when it is used.</p>
<p>Most of the advice I've been seeing about bringing fountain pens onto airplanes is that one should either completely fill them, or leave them completely empty before boarding the plane. However, this only works for <em>storing</em> the pen while in flight, and not for actually <em>using</em> the pen while in flight.</p>
<p>How can I effectively use a fountain pen while on an airplane? Is the only way to leave it empty and to fill it while onboard? I can think of a design for a pen that would allow it to be used on a plane effectively (store the ink in a bladder that changes size), but are there any pens that work like that?</p>

CC BY-SA 4.0
2020-08-14T09:15:51.500Z
This isn’t an answer just a thought, use a pencil. That’s what the Russians did in space rather than spend money to develope a pen like the US did.
Jim
CC BY-SA 4.0
2020-09-13T01:07:49.673Z
@Jim True...but that was a bad decision by the Russians. If the pencil tip breaks, it would hover around and could get into someone's eye or into some critical instrument and damage something.
gparyani
<ink><pens>
How can I use a fountain pen while onboard an airplane?
gparyani
# How can I use a fountain pen while onboard an airplane?

(Asked by: username_0 on 2020-08-13)

When a fountain pen is onboard an aircraft, it can leak ink due to the strong pressure difference inside the pen vs. outside the pen. This can result in messes to clean up on the flight even if the pen is not used, and at best ink blots when it is used.

Most of the advice I've been seeing about bringing fountain pens onto airplanes is that one should either completely fill them, or leave them completely empty before boarding the plane. However, this only works for *storing* the pen while in flight, and not for actually *using* the pen while in flight.

How can I effectively use a fountain pen while on an airplane? Is the only way to leave it empty and to fill it while onboard? I can think of a design for a pen that would allow it to be used on a plane effectively (store the ink in a bladder that changes size), but are there any pens that work like that?

**Tags:** ink, pens

> **Comments:**
> **username_1**: This isn’t an answer just a thought, use a pencil. That’s what the Russians did in space rather than spend money to develope a pen like the US did.  
> **username_0**: @username_1 True...but that was a bad decision by the Russians. If the pencil tip breaks, it would hover around and could get into someone's eye or into some critical instrument and damage something.  

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## 3 answers

### Answer by username_4 on 2020-08-13. Score: 4

There are things you can do to reduce the risks, as described in the other answers, but I would be wary of using any kind of pen containing liquid ink on a plane (although a "felt or fiber tipped" pen may be OK; never investigated that). I've had a Pilot Precise technical-style pen that uses disposable refills (the entire guts of the pen), leak while sealed in the tip-up position.

If you need to write on a plane, pens with gel ink (which also includes most ballpoint pens), are much less likely to leak. The best type would be a Fisher "Space Pen" (various other pens can also use those refills). These are manufactured pressurized and are designed to use that pressure to feed a very thick ink without leaking (they can write in the vacuum of space without leaking). If writing with a fountain pen is important, I would just wait until you land to do it.


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### Answer by username_2 on 2020-08-13. Score: 2

There are flexible ink receptacles for fountain pens known as **ink sacs** or bladders, like these:

[![enter image description here](https://i.sstatic.net/2tNnt.jpg)](https://i.sstatic.net/2tNnt.jpg)  
[source](https://www.youtube.com/watch?v=Sjjnxz_lrBU)

However, **they apparently don't give any advantage over rigid cartridges** when it comes to air travel ([here](http://www.fountainpennetwork.com/forum/topic/325676-how-do-parker-51s-do-with-air-travel/#entry3891145): "*sacked pens also have trouble with rapid pressure changes*", which is understandable as the material is quite rigid).

What you can do, is to **always point the nib upward**, as any air in the cartridge or sac will expand during cabin pressure adjustments and will force the (negligibly influenced) ink out of the nib. Having the nib topside will minimize potential flow.  
This is also why **having the cartridge completely full** (that is, without any air inside) causes the least leakage problems.  
After having used it (and before descending) you can always take out the cartridge and place it in a sealable container or bag.


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### Answer by username_3 on 2020-08-13. Score: 2

If boarding with it completely full prevents leaks in storage, that's because there's no bubble of air at ground pressure in the ink. That means you should be able to use it without a problem.


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