April 1, 2000
Mark R. Twombly
No one told me when I was learning to fly that aircraft range and endurance have absolutely nothing to do with fuel consumption, fuel-tank capacity, or winds. Range and endurance are strictly functions of the weakest bladder aboard.
I’ve been there—at cruise altitude, power set on best economy, wind at my back, good weather ahead, and cleared direct. That’s when it starts. An almost imperceptible pressure creeps into my gut. It isn’t painful; it’s just there, like an unpleasant thought lurking at the edge of my subconscious that I can’t shake.
I can bear a certain amount of discomfort, but at some point the pressure deep within my abdomen becomes unbearable—even approaching a safety-of-flight issue, or so it seems in my desperate state. Occasionally the mind exerts control, ignores the mounting pressure, and whispers, "Press on," with no hint of the irony in the command. I smile confidently, loosen the seat belt some more, then nudge the mixture control forward to the best-power setting, hoping for a precious few more knots.
"Wow, it’s beautiful up here!" I exclaim aloud, hoping enthusiasm will overpower the stirring.
It’s no use. Who can ignore a filling bladder? We clever humans have figured out how to plant hair on our thinning heads and harvest fat off of our thickening bodies, but we haven’t yet mastered the physiology of our internal plumbing. The fact is, restrooms rule. If you’re not convinced, spend a couple of hours at the FBO watching arriving aircraft. What’s the first thing pilot and passengers do after exiting the airplane?
It’s a problem. In several important ways, flying small aircraft is incompatible with good drinking habits, and I’m not even talking about beer.
For example, a cup of coffee or two helps most of us to be sharper pilots on those early morning flights, but coffee is a diuretic—it stimulates the production of urine. Those of you who wake up with the help of regular soft drinks instead of coffee are no better off, because the diuretic culprits are caffeine and sugar.
Another thing: Aren’t we supposed to drink lots of water each day to ensure that our cells are always awash in liquid? Pilots, especially, should drink plenty of fluids to guard against potentially dangerous dehydration. Of course, that flood of water only fills the bladder faster.
Faced with such conflicting concerns, we deal with it. My partner always carries a small cooler of diet soft drinks on cross-country flights, but he has an ironclad rule that he does not open one until 45 minutes from the destination.
I will—I must—drink one cup of coffee before a morning flight, but I try to down it as soon as I wake up, hoping there is time for my kidneys to process it and forward the waste liquid to my bladder for dispensation before taking off.
As for hydrating in flight, I do. I carry a bottle of water and sip from it whenever the mood strikes. I wasn’t always so bold. I used to practice abstinence, but I’ve come to realize that my older and wiser body is more susceptible to the effects of dehydration and fatigue, especially since I live in a hot, humid climate.
I cope with the consequences of my in-flight drinking by carrying a red half-gallon plastic jug shaped like a fire hydrant. Get it? Ha ha. It has a secure, leak-proof cap. The fun part is carrying that bright red jug across the ramp and into a busy jet FBO, where bored professional pilots and impatient corporate execs enjoy watching my march to the restroom. They know what’s in the jug.
I’ve also provisioned the seat-back pockets with a couple of plastic bags containing a substance that turns urine into a nonspilling gel. These are for passengers’ use, especially females, because each of the bags has a plastic neck shaped to accommodate the female anatomy. Not surprisingly, I’ve never had a woman passenger use one.
Dr. Davis Gates, a local urologist, pilot, and owner of an airplane with bladder-busting fuel capacity, has created his own relief device. He takes a one-gallon plastic bag, the kind you can press closed, inserts it in another such bag, then stuffs the original bag full of cotton. The cotton absorbs all of the urine you can pump into the bag, according to the good doctor, so there is no liquid to spill if the bag isn’t completely closed and happens to overturn. Plus, increasing atmospheric pressure during the descent from altitude helps to keep the bags shut tight. Clever, that doctor.
One of the airplanes I fly is equipped with a black plastic venturi tube mounted on the bottom of the fuselage under the cabin. A rubber hose connects the tube with a funnel stashed under the front seats. The venturi creates constant suction in the funnel and hose, so when you gotta go, you can.
My partner and I have purchased one to install in our airplane, but our mechanic is concerned about the corrosive effects of the urine spraying along the length of the bottom fuselage. He recommends that we mount the venturi under the tailcone. I worry about kinks forming in that long line and the uphill flow when the airplane is in level flight.
These important issues are unresolved in our minds, so I’m still peeing into a fire hydrant.
Pilot Safety and Skills,
Aircraft Power and Fuel,
Pilot Health and Medical
A House bill that would force FAA to go through the rulemaking process before imposing new policies for sleep disorders has passed a key committee.
Your mission: Fly with eight F-15s to the Philippines, rejoin, refuel with air tankers, engage an unknown number of Red Air fighters, refuel again, and then return home to Okinawa. And fly with radio silence up to the first contact with the Red Air fighters.
Shell announced Dec. 3 the development of an unleaded aviation fuel that will be submitted for certification as a "performance drop-in" avgas replacement.
AOPA thanks our members for their continued support in protecting the freedom to fly.