Questions from the Cockpit: Fire starter

Rachel, a CFI from Colorado, writes: Hey, William, I read with interest your recent piece on breaking the VSI in an emergency. I’ve also heard that you can break a whiskey compass and use the liquid to start a fire in a survival situation. Is that true? Also, why are they called “whiskey compasses,” it looks more like Aviation Gin to me!

I’ve heard about starting fires with compass fluid, too, but I wasn’t sure if it was mythology or a real thing, so I broke out the ultimate guide to the ultimate bad day in aviation: The FAA’s Basic Survival Skills for Aviation (OK-06-033), to see what it had to say.

And, lo and behold, it does mention using compass “oil” for fire starting, along with using your air filter for kindling. No kidding.

And, according to the book, if you don’t have a match, just use the landing light lens like a magnifying glass to get the fire going.

Meanwhile, if you run out of compass fluid, the fluid from the turn and bank (if so equipped) is also flammable, as is brake fluid — although the degree to which it is depends on the type.

But then I began to wonder if all of this was still true or is it just something that was true in the past? What about modern compass fluid? So I wrote to Airpath, who seem to be the makers of most traditional GA compasses, and asked them if it was possible to torch their product. 

Surprisingly, they didn’t respond. 

But luckily for you, I happen to have an old whiskey compass. An Airpath at that. So I took your question into my own hands and conducted some hangar mad science to get at the answer.

First, know that you don’t need to break the thing. It has a screw-off lid on the top for servicing. If you have a glare shield or windshield-support mount compass, you could probably open it in situ. The lid has a rather wide tool grove, just the right size for a dime, so you might want to add a Franklin Roosevelt to your survival kit.

If your compass is panel mounted, it’s probably the easiest of all instruments to remove. Use the screw driver on your Leatherman or Swiss Army Knife and simply unscrew it. Being largely self-contained, it has no difficult hoses or connectors (some compasses are lighted, but the wires are thin) and it will pop right out. You probably have to be a licensed A&P mechanic to do this legally, but if you’ve crashed in the woods, who’s gonna know? 

I opened mine up, and took a cautious sniff of the fluid. It ain’t whiskey or gin, that’s for sure. It smells vaguely petroleum-like, if you know what I mean. Not quite avgas. Not quite oil. Not quite Coleman lantern. I heard somewhere that the fluid is a cousin to kerosene, but it didn’t smell like Jet-A, either.

I took a bamboo knife left over from the Frito Pie hangar lunch at the Ercoupe Nationals, and broke off a long splinter to create a match, which I then lit with my trusty Zippo. I touched the flame to the top of the liquid in the compass and… 

Nothing happened.

I was totally bummed. I had pictured the fluid burning like a miniature bonfire atop the compass, which would have been an awesome illustration for this column. Well, crud. All it did was smoke a little, and the smoke clung to the surface of the fluid like San Francisco fog to the bay.

Now, because I had no idea how old the fluid in my compass was, or if the fluid used has changed over the years, I hedged my bets by buying a bottle of compass fluid from Aircraft Spruce for a $1.97 for a ½ pint. It reassuringly said COMBUSTIBLE in bold, black capital letters on the bottle, right under DANGER, which was underlined, just to make the point.

I poured a small puddle on a metal tray and tried to light it up. Again. No go. Seriously? What’s a guy gotta do to start a fire? I was beginning to wonder if this was one of those aero myths. 

Not to be deterred, I dipped the flaming match deeper into the fluid, and accidently extinguished it. Clearly, it would have been one cold plane crash for me.

But when I re-lit my “match” I made a discovery. It lit up like a frickin’ forest fire. OK, compass fluid may not burn well on its own, but it’s one heck of an accelerant when added to anything flammable. Get out the marshmallows and wait for rescue! 

You do have marshmallows in your survival kit, don’t you?

FYI, I later found a safety data sheet for Airpath’s compass fluid on Sky Geek, which identifies the whiskey as isoparaffin solvent made by Chevron Phillips. It’s apparently a synthetic hydrocarbon, which is also used in paint, printing ink, hand cleaners, and dry cleaning “soap.” The particular flavor used in the compass fluid, Soltrol 130, is a Category 4 Flammable Liquid, which is the least flammable class of flammable liquids.

Oh, and you definitely don’t want to drink this whiskey to keep warm. The sheet cautions us that it can be fatal if swallowed.

As to the whiskey in the compass’s name, there are two prevailing theories on the origin of the term and I don’t buy either one of them.

The first is that early compasses had alcohol in them for a non-freezing substance, and hence got the nickname “whiskey.” That doesn’t make sense to me, due to the color difference. Compasses have a clear liquid and any respectable whiskey is some degree of amber — the darker the better, in my experience.

The second common explanation for the origin of the name is that the proper name for the device is wet compass, and the acrophonic for W is whiskey, so it made sense to shorten wet compass to w-compass, and then to whiskey compass to make it sound all aviation-like.

The problem with this theory, as charming as it sounds, is that W didn’t become whiskey until after World War II. Prior to that, it was William for a couple of years, and prior that — from 1920 through 1946 — it was Washington. You’ll note we don’t have any Washington compasses, although perhaps some people there could use one.

So where does that leave us? With a mystery. At least for now.

It goes without saying, but I’ll say it anyway: If you have a vertical card compass you are out of luck. At least when it comes to whiskey for compass fires. They are dry, literally.

But all is not lost. Your airplane comes equipped with avgas, which is easier to get to anyway, and burns just fine. And even if you crashed from fuel exhaustion (don’t you dare) there are still several gallons of “unusable” fuel in each tank.

Avgas, by the way, is a Cat 1 flammable liquid, the most combustible. And even if you’re down to just the unusable volume in the bottom of each tank, it’s a heck of a lot more fire starter than the two ounces of isoparaffin whiskey in the compass’s “tank.”

William E. Dubois is a double Master Ground Instructor accredited by both NAFI and Master Instructors, a two-time National Champion Air Racer, and worries more about the plane catching on fire all by itself after a crash than he does about trying to get a fire started himself.