Refraction Distraction

I walk towards my airplane on the ramp and I can see that it is pissing fuel out of the left wing, a steady stream, not a drip but a spray like it's pressurized. I remember the wide-eyed horror I felt the first time I saw fuel streaming out of a parked airplane. Today my feeling is just, "Hmm, this had better not be something bad." I could write a long blog post on various reasons that fuel has dripped, flowed or sprayed out of my parked airplane. I duck under the wing to look at the source. It's coming out of a vent. The vent is recessed so that incident air doesn't pressurize it, but it still faces forward so the stream spurts out in front of the wing. There's no visible damage. To confirm my first suspicion about the cause, I open the fuel cap for that tank. The tank is completely full and some fuel flows out of the filler neck onto the top of the wing. Suspicion confirmed.

This airplane was fuelled last night while we were wearing sweaters and jackets on a rainy, overcast day. Now I'm wearing a t-shirt, and the angle of the sun over the hangar puts the left wing in bright sunlight. The fuel is expanding inside the wing and being forced out the vent. It's perfectly normal. That's one of the reasons the vent is there. (The other reason is so that as fuel is burned, air can get in to replace the volume so that the fuel will continue to flow).

The fuel stain on the ramp looks nasty, but the rest of the airplane is fine. I set up what gear I have, conscious that the bag in which I normally organize my spare batteries, extra flashlights, snacks, waterbottle, and the like is packed inside my checked luggage. I have enough equipment to be safe and legal, just not everything I usually have.

All is normal on the run up, and I talk to the flight services guy in the tower and then take off. I say good bye to flight services guy but continue to monitor his frequency, and tune 126.7 on the other radio for en route traffic. At eight-thirty in the evening up here the sun angle is like four in the afternoon down at the 49th. It's hot in the cockpit, but I need to run the heater for the comfort of the picky computer equipment in the back. I spend a while moving vent sliders around trying to make it comfortable for me, and cozy for the computers, too. The mission specialist goes off headset for a while in order to take off his fleece.

Not only have I not flown in three months, but they have changed out the type of equipment I am using, so I'm looking at a screen I haven't seen in about a year. I stare at it for a moment, trying to remember where it means I'm supposed to go, and then I go to work. I remember this. I know how to do it. I'm good at this. Somehow my temperament--and bladder--is suited for this type of flying. I settle back into my routine, burning an hour of fuel out of each set of tanks so that nothing is so full it's spilling out the vents, and then systematically work through the various tanks. I plan to land at 2:15 a.m.

There are a couple of pilots in Cessna 172s hopping around beneath me, position reporting between small places I saw on the map. They chat to each other about how fine the weather is tonight and where they are going. As they say their call letters I picture them painted on the side of the airplanes. I remember things better visually then as sounds. One of them is CXD, which trips a switch in my head because they are all letters used in Roman numerals: 110-500, not that that means anything. When there's a break in their conversation I call up CXD and ask them what they're doing, just trying to join the conversation. The answer is a fairly terse "flying from Worsely to Fairview." And then they stopped talking to each other. I guess they forgot they weren't alone up here.

Fifty gallons of avgas later I'm still in the sky and so is the sun. My hat is in my checked bag, so I have to depend on my skinny sunvisors and my sunglasses for protection from that ball of fire. I estimate it is still fifteen degrees above the horizon, maybe a little less. When will it set? When I'm flying I can't put my whole brain over to arithmetic, because I'm looking out the window, manipulating the controls, squinting at my screens, and paying attention to all the little things I don't even realize I'm looking at. So I chunk arithmetic up into easy bits. Three hundred sixty degrees in twenty-four hours, one hundred eighty in twelve, ninety in six, forty-five in three, so fifteen degrees an hour. But I know it will be in the sky for a lot longer than an hour. The sun doesn't go straight down here, it moves diagonally towards the horizon. At my latitude, three weeks before the solstice I suppose I could calculate its angle of descent and use trigonometry to determine when it will reach the horizon. But I just eyeball it and estimate that it will hit the horizon at about eleven. If I were a few degrees further north and it were a few weeks later it wouldn't go down at all. It would just slide around the edge of the horizon before angling back up.

I didn't see the exact moment it ducked behind the horizon, I just turned and saw that it was no longer trying to burn my eyeballs. It was about eleven. It's still light, but the light is more orangeish. I try to picture the refraction process that is making the light orange. I'm pretty sure it's the same reason that the sky is blue. But is it because the red light is refracted more by the atmosphere or less? I think the blue is refracted more, because the blue is on the inside of the rainbow, but I can't quite picture it. Now that I'm on the ground I could look it up, but I'll give you my airborne thought processes. I think that as the sun's rays hit the atmosphere at a low angle the blue is being refracted up away where I can't see it, but the red is refracted less, so it's the last colour I see. There's a moon, too, and its light is whiter. An hour after sunset it's not really dark yet. I can still see clouds in the distance and the shapes of lakes on the ground.

I call flight services for an altimeter setting. It hasn't changed in over four hours. 'Are you coming in to land now?" he asks. No, we have another couple of hours.

The mission specialist is tired and calls it done a little early. We touch down just before two a.m. I chat to the FSS guy on the way in, "when do you get to go home?" It turns out that he worked the day shift and then got called in to do the overnight, so he'll be there until 8:30 a.m. Nasty. I tell him he'll still be there when my flight partner comes on shift in a few hours. He asks her name so he can say hi. I forgot to ask his name.

I'm hungry enough to eat the seven hour old sandwich I bought before departure, and tired enough to go right to sleep.