Can I take a compass on a flight?
People often ask questions about taking a compass on a plane.
“I’m due to go on a hiking holiday later this year. Am I okay to take my compass on a flight or will it negatively affect the compass? If okay, is it better to store it in the hold luggage or take it with my hand luggage?
Didn’t know whether the pressurised hold luggage cabin could cause problems or if in hand luggage whether the security scanners might cause problems to the compass. Also, I’m aware there is liquid within a compass, but guess that shouldn’t be a problem as it’s below 100ml.”
I have never had a problem and I have flown with a compass lots of times. To answer your questions, follow the usual advice and keep it away from anything magnetic. The modern X-Ray scanners at airports should not affect your compass.
The small amount of fluid in the housing Is sealed, so should not upset security staff at most airports either. But bear in mind though, that most airport security staff may not realise the fluid in some compasses may be flammable, however, if they do, they might not be happy with it in the cabin, however small the amount.
As for carrying it the hold or hand luggage, the whole aircraft will be pressurised to around 6000 feet, which is lower than your compass has been if you have walked say in the Alps, so your compass should not be affected by the aircraft pressure in flight. If a small bubble appears it is fine, as long as is not large enough to affect the needle moving freely.
It is rare, but some mobile phone batteries can spontaneously catch fire, and if next to your compass and the fluid in your compass is flammable, even the small amount involved may help the fire a little. So keep the compass and phone apart. It is also good practice on the hill anyway, because the phone can affect your bearing when held close to your compass.
If you are interested in the direction your flight is heading and get your compass out, remember your compass won’t be accurate when sat in the metal fuselage. The aircraft’s compasses are adjusted for this when installed.
The main thing to remember though is always check your compass before you head on the hill. It may have been magnetised by say a phone or speaker in transit. Assess the direction of Magnetic North by using land features around you, and the map, to check that your compass has not polarised (reversed). Ask the group to check theirs while stood a metre apart too and compare results.
The Red Needle should be pointing to Magnetic North. If the White Needle is, the compass has reversed, and needs fixing by the manufacturer, or by you at home. Read our blog article how to fix a reversed compass.
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The Ultimate Navigation School is a charity providing navigation training to hill walkers, with all our net profits supporting the following charities:
Mend Our Mountains, Fix the Fells, John Muir Trust and Mountain Bothy Assoc.