In the cab to the hotel one night last fall, the cab driver was oddly non-responsive to comments. He seemed alert and sober, and friendly, just didn't seem to get much of what we said. It wasn't until we got to the hotel and encountered the same thing that it dawned on me what the issue was. We're far enough north that English isn't the language people speak in their homes or with their friends. You must think I'm a dolt not to realize that I was talking to someone for whom English was not a first language, but he spoke English with an accent and manner that I'm perfectly used to. It has persisted in monolingual English communities further south, and because of that I though of it as a northern native accent, and not as an indication that he wasn't comfortable in English. It's a fascinating phenomenon, what remains of a language after a population stops speaking it, and how long those remnants can persist. (I suspect I'm touching politics that aren't my own when I say that there is an accent and manner of speaking typical of Americans who are descended from people who spoke west African languages, even though they haven't spoken anything but English for generations). I'm glad that despite the horrific ways people who looked like me tried to assimilate these people's ancestors, that they still have their language and a community in which to speak it.
It's summer, so it's warm on the ground, warm enough for me, anyway. Twenty-five Celsius (that's the only name of an SI unit that gets capitalized in English when it is spelled out in full-- oh SI, why must you be so?) is as warm a day as I ever need. But as we go up, the temperature goes down, by two or three degrees per thousand feet, such that it is twenty below at altitude. It's a short flight so after a couple of hours I'm doing my top of descent checklist, including "fuel on fullest tank." I reach for the left selector to bring it aft to the inboards, where I usually keep my reserve fuel. It's already on the inboard tank. So I pull it forward to the outboard. The airplane is approved to approach and land on inboard or outboard tanks. I do the same for the right tank. The engines begin to sputter. I switch back to the inboard tanks, because returning to the previous configuration is what you do when you're a pilot and something bad has happened right after you made a change. The engines run much better on the inboard tanks. But why? The outboard tanks are full. They were filled at the same time with the same grade from the same truck as the inboard tanks. And how much of a problem is this. I can probably reach my destination with the fuel remaining in the inboard tanks. I had better be able to, because there is nothing closer, in any direction, (nor anything further for maybe a couple of hundred miles). It's kind of flat out here, but I haven't made the transition from considering what embarrassing way this flight could end to what dangerous way it could.
And then I realize what the problem is. It's a design issue with this airplane. It's not in the pilot operating handbook. It wasn't in the training. I know of this problem because about six months ago I parked this distinctive airplane next to a sleek jet and the captain who stepped out of the jet had flown airplanes like mine in Tibet. He had fond memories and reminisced a little in the sixty seconds that we were walking in the same direction at the same time. He led his recollections with "great airplane," but then I nodded and laughed as he ran through some of its weaknesses. One of his comments was unfamiliar and I thought then that he might be referring to a different model. The manufacturer did make changes over a few generations. The old pilot had said something about only being able to switch from outboard to inboard tanks, and of course I knew that I could switch between the tanks in any order. But the back of my brain had filed what he said, and given current context the meaning becomes clear. The tank selector mechanism has frozen in some way so that although I can move the selector lever, the tank being accessed doesn't change. If this is right, the outboard fuel might be accessible after I'm through the freezing level. But I don't want to waste my gravitational potential energy by diving at high speed to a lower altitude. Drag increases with the square of the airspeed. I descend to below the freezing level on a normal profile, checking periodically to see if the fuel will flow from an outboard tank. A few minutes after the outside air temperature flickers above zero, the fuel flows normally from both tanks. And there's an item to add to the training file.