How can I use a fountain pen while onboard an airplane?

Question

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?

Answer 1

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.

Answer 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.

Answer 3

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

^source

However, they apparently don't give any advantage over rigid cartridges when it comes to air travel (here: "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.