Runner's High

This story starts about five years ago when I first realized that combining my fondness for running, maps, and cool watches in one technological device was possible and affordable, even if it did barely fit on my wrist. I bought a Garmin Forerunner 305. It's essentially a stopwatch integrated with a GPS, heart rate monitor, and computer, so I can know where I am, how fast I'm going, and how hard my body is working to achieve it, all at once. And then I can upload the resulting data to my laptop and stare at it in tables and graphs and maps to come to conclusions like "I get really tired when I run up mountains" and "I should run faster." I used to come to such conclusions without the technology, but now I have data to back it up. It's ludicrous how much more fun it is to go running when you get statistics at the end. I don't remember how I ever went running without a box on my wrist telling me if I was doing it right or not.

I took my GPS watch in my flight bag everywhere I went, so that if I had time to go running at the end of the day, I'd have the motivation of knowing how far and fast I was going, and also so I could activate the "Return to Start" feature. Return to Start gives turn-by-turn directions to get me back to the hotel, regardless of how identical the suburban streets, wooded trails, or gravel road turn-offs appear to be. I don't know that I would be still wandering around a highway truck stop somewhere without it, but there's more oxygen deprivation in my brain after fifteen kilometres of pushing my pace than after five hours of sucking supplemental oxygen through my nose at 17,000'. It's nice not to have to worry which forks I took in the trail network of an unfamiliar town.

I have my data all in Garmin's Training Center software: years of runs from Alaska to Florida and many where I have to zoom out on the little map several times before I figure out which little town with limited map information is traced by the record of my exertions. I like to review this data and use the Training Center "Compare" feature to virtually race the years-ago Aviatrix. (I'm pretty sure I can still take her). But while I've become sleeker, faster and more resilient with the years, the watch hasn't fared as well. It became harder to charge, and reluctant to connect to the computer to give up its data. The beeping sounds stopped working, and then it started shutting off in mid-workout. It's well out of warrantee, and the model is discontinued, so I had to choose a replacement. I could probably export the data in a standard format. Garmin is so prevalent in the GPS field that any manufacturer that couldn't convert or use their formats might be a little silly. But my first choice was just to stick with Garmin.

Their website is a mess of poor feature explanations. It doesn't suggest an upgrade path from the 305 to another product. I didn't find an overview on what the focus of the Forerunner, vivo-, or fēnix lines is, nor could I see any coherent logic to the Forerunner model numbers and suffixes.

I thought I'd had an e-mail conversation about this back when the Forerunner was still available and one could send it in to a Garmin-approved dealer for a flat-rate "repair" (obviously a replacement with a reconditioned model, but it was worth the $75 for me back then). Mining my e-mail archive for "GPS watch" found me all my old blog posts that mention "GPS" and "watch". The insane detail I included allowed me to relive some interesting flights and revisit all manner of places. No wonder people who weren't on the flights to begin with enjoyed reading them. This has somewhat inspired me to find a way to keep blogging about them. Perhaps I'll talk to the owner about the blog.

I tore myself away from my former adventures to google up second hand explanations and information on features and backwards compatibility of Garmin products. There are SO many models. Finally I decided to artificially limit my choices by going to a store and making my selection from only what they had. I took my flaky old Forerunner with me, and on the bus ride there, noticed that the crack between the layers of the case was quite wide. With no prying or wiggling, I lifted the face of the watch right off the back, revealing its electronic innards. Well no wonder it wasn't staying on, charging and connecting. I was lucky it hadn't fallen apart during a run. I feared I had killed it by carrying it with me everywhere, including into the flight levels in an unpressurized airplane.

The higher you go in the atmosphere, the less air there is on top of you, thus the less pressure you feel, so that instead of being all squished together to sea level pressure, the molecules are all spread out. One breath takes in less oxygen, unless I supplement it from a tank, which I do, through the aforementioned nose tubes. Anything with air sealed into it that I bring up from ground level retains the same pressure inside that it had on the ground. As it ascends, the differential between the inside pressure and the outside pressure increases, producing a force acting to expand the sealed container. The tank full of breathing oxygen is cylindrical, and its strong walls and robust valves are inspected weekly to ensure that as the pressure outside the tank decreases, the tank will not rupture, bulge or leak from the added force. Potato chips are deliberately packaged with trapped air, to protect the chips, and their bags will bulge out drum-tight, and sometimes burst, as we ascend. The gases in our intestines and ear canals expand and escape through the usual routes. I was afraid that the air sealed into my GPS watch damaged it. But then I realized that the Forerunner 305 isn't waterproof, and my Timex wristwatch, which works perfectly, is. (I'd tell you what model Timex, but it's so old that all the words have worn away, and the chunks of decorative plastic stuff have fallen off, leaving a bare case with buttons on it). A little more research showed me that plenty of people had their Forerunners come apart, sometimes falling off bike mounts and/or being run over by cars.

I got to the store and interrogated the clerk about the selection. I was almost ready to buy a Garmin Forerunner 225. It has the heart rate monitor integrated in the watch itself, with no need for a chest strap. It has a built-in accelerometer to give pace and distance information on indoor treadmill runs. "What about winter?" I asked. "Can I use it with a chest strap in the winter, when I wear the watch on the outside of long-sleeved garments?" To answer this question, the clerk went not to the Garmin website, but straight to the blog of DC Rainmaker, an obsessive sports technology reviewer. I'd encountered one of his reviews while googling for compatibility information earlier, and not noticed that everything I could ever want to know about pretty much any sports watch is on this guy's blog. The Forerunner 225 will pair with a chest strap, for people who mount it on bicycle handlebars, as well as winter runners, but it was missing a couple other features that I wanted. Indeed none of the watches they carried had the Back to Start feature, so I went home without buying any of them, and went back to DC Rainmaker's site.

Ray Maker (get it?) conveys the excitement of taking a new electronic toy out of the shipping box, gazing at its packaging, and then breaking the shrinkwrap. He includes photographs detailing the plastic bags and twist ties containing all the sub-components of the products. He does more running, biking, and swimming to test one device for a review than some buyers will log in the lifetime of their device. Every review is ridiculously detailed. Some people would say too detailed. So a little like many of my blog entries, if I did way more research. It parallels the way I'd like to blog if I had the diligence to drill down to the technological and legal root of everything I said, rather than speculating and drawing on knowledge already in my head. It made me cheer a little when I found a typo now and again, on his site, because it just goes to show that typo-free is not a requirement for an insanely awesome blog. He also displays a lot of integrity: he borrows and returns all reviewed gear despite the fact that his reviews are clearly enough work to deserve a lot of freebies. If you run or bike and like gear, you almost certainly already know his site, but if you don't you're in for a treat. If you never do anything more energetic than opening the refrigerator, but just like tech, especially GPS, you'll probably still want to read his site. The comparison tool there allowed me to quickly determine that the correct watch for my needs is the Forerunner 310XT. It wasn't at the store nor prominent on Garmin's website because it is ALSO being discontinued. I decided to get one now, through a site DC Rainmaker partners with, to compensate him for the work he does. I had some trouble with that site, so posted a comment on his blog, and as I was already thinking of blogging about the experience, I signed the comment "Aviatrix."

It turns out that DC Rainmaker is a long-time reader of Cockpit Conversation. It made me feel like a member of an elite when he asked if I was that Aviatrix. As I told him, some days I’m convinced that there are far fewer people on the Internet than is generally thought. Maybe it’s just you, me, the awesome people who comment on our blogs, and a lot of Chinese spambots.

Meanwhile I ordered a Forerunner 310XT somewhere else, bound my Forerunner 305 together with rubber bands, found it worked perfectly, glued it together with silicone sealant (as recommended by several people on the Internet), and am currently in high level discussions with my printer on why it should print the return mailing label for the 310XT. When the 305 gasps out its final beep I'll do this again, probably with a whole new set of features. I might get one of the "lifestyle" watches that track your every move, including sleeping.

Death Rates

I'm IFR in the flight levels on a clear VMC day. The IFR part means I'm following a set of rules and procedures ("Instrument Flight Rules") designed for pilots of aircraft in weather conditions that don't allow them to navigate by looking out the window. The flight levels part means I'm flying above about 18,000'. In Canada the "transition altitude," between altitudes designated by the local air pressure and those altitudes designated by a universal standard pressure setting, is 18,000'. One never flies at 18,000', but instead sets the altimeter to 29.92 and flies at flight level 180. I don't know how our transition level was determined. Our highest mountain is about 19,000', so it wasn't set relative to that. VMC is "Visual Meteorological Conditions," that is weather that permits navigation just by looking out the window.

So why am I IFR in VMC? Because in Canada everyone operating in the flight levels is required to do so under an IFR clearance. It's a safety regulation. I have to fly only as directed and cleared by ATC, in order to ensure separation from all other aircraft. And I'm up this high because this is where I need to work. There's only half as much air pressure up here as at sea level, which means only half as much oxygen per breath, so I'm wearing a mask that provides me with supplemental oxygen. The masks do a great job of that. Testing my blood oxygen level always shows me at 98 or 99% saturation, the same level I get sitting on my chesterfield at home. (The tester looks at my blood by shining a light through my fingernail: it doesn't take a blood sample). Only problem is that in providing a tight seal around my face and being secured to my head underneath my headset, the mask give me no opportunity to eat or drink during the flight. Air before food.

The mask also interferes with the seal between my headset earpieces and my ears, so it's a little noisier with the mask on. Even noisier when my noise cancelling cuts out because my headset batteries died. I'm not sure if the noise cancelling "works harder" to keep up, or if it has the same battery consumption regardless of the ambient noise, and this is just coincidence. I use rechargeable batteries, which when they are new last about fifty hours in the airplane before they die, but after many cycles have shorter lives. I have numbered all my rechargeables and track how long each set (the headset takes two AAs) lasts before it dies. When they can't go a full flight, they get retired to a plastic baggie in my kitchen. Eventually they will go to recycling, when I figure out where to recycle rechargeables. They last pretty well: there are only six batteries in the retirement baggie and I've been using rechargeables in my headset and flashlights for at least eight years.

I change batteries and then notice I'm off my heading. The autopilot has disconnected. I must have hit the button. I reset it and then turn to a new heading, but something doesn't look right. The GPS says I'm going where I want to be, but the heading indicator is way off. I reset it to the compass, and it follows for a while, but soon loses interest again. The heading indicator is powered by two engine driven vacuum pumps, one of which I reported close to needing replacement a few days ago. The suction gauge shows slightly less of a vacuum than ideal, but in the green range and no less than it has for a few weeks. The other part of the instrument shows both vacuum pumps on line. The attitude indicator, powered by the same system, still appears to be working. Legally I'm required to inform ATC of the failure of a heading indicator. I do so, and they seem confused. No, it isn't affecting my operation at all. I'm using an electronic guidance system, and I will be landing at an airport that I'll be able to see sixty kilometres away. I don't need it for the flight. Maybe people don't routinely comply with that regulation anymore.

Before I land, the stupid thing comes back to life. Charming. I'm far from base, but I call maintenance so they can order one, or pull one out of another plane or something for when I come back. They don't have any troubleshooting tips for a zombie heading indicator. It's working now, but it's not reliable, so I snag it. That is, I write in the journey log that it is not operating correctly. This will limit our operations to day VFR (the looking out the window counterpart of IFR) only, which is a huge pain in the neck, because it prevents me from continuing the work above FL180, even though its effect on safety is negligible. I have had transient problems with equipment that never recur, but usually they hint at trouble and then throw a full failure if ignored. I think I've only seen simple heading indicators (as opposed to the more expensive and complex HSI) fail twice before in about 7000 hours of flying. And one was a simple fix, turned out that there was an installation error that had made a screw come loose. I wonder if the suction line is leaking or blocked or something. Nothing I can do about it, anyway.

Paper or Plastic?

So we're about to evaluate the electronic cockpit. That is have all the charts on an iPad. Eliminate the two boxes of maps in the cockpit, the express ordering of charts for regions we suddenly have to venture, the hunt for a vendor that has the new VTA in stock, and possibly the chore of checking the charts periodically to see if a new one has come out. (Canadian VFR charts do not have a predetermined expiry date: there is a website that lists the probable release date of updated versions, but that list is a bit like the to do list that indicates when I will clean my kitchen or get my hair cut: that is, almost never happens on time.

The proposal presents two contradictory reactions. The progressive, "hey cool stuff, think of all the things a computer can do that paper can't" is checked by "wait a moment, what about all the basic stuff paper can do that e-charts can't?" In this blog entry I'm going to ask the questions, kind of make myself a to-do list for research and experimentation. I'll start with the strengths and weaknesses of old fashioned paper because that's what I know best.

• You can spread paper charts over the whole wall/bed/floor to get a big picture of where you are going. To be fair, this is also a weakness of paper. You have to have a large surface to see a long VFR trip in one go. Given that I can presumably scale in and out at will on the electronic one, I think the only thing I lose here is the physical scale, and to tell the truth I haven't done the multi-chart array thing for ages. Ooh, except that I had a couple of interns put together one on the wall of the office, and that's damned useful. But that won't go away.
• Paper charts don't become useless when broken. Paper charts retain most of their usefulness despite being dropped on the floor, stepped on, ripped in half, slammed in the door, having water spilled on them (they're pretty good quality paper) and other indignities that they suffer regularly. The destruction of one paper chart does not eliminate access to everything else on board. The robust case Transport Canada requires for an iPad should partly address this, but is this concern founded or not? I've never heard anyone say, "Our iPad just crashed, in the missed approach." Does it happen?
• Paper charts are temperature and pressure independent. (At least up to 451F). I have had electronic equipment fail for me because it got too hot or too cold, and I suspect my running computer stopped working because it was depressurized on a daily basis. We'll stress test one of the units (i.e. subject it to normal operations) and see how it does.
• Paper doesn't glare or wreck your night vision. anyone who has tried to use a computer near a window knows how hard it can become to read in the sunlight, something my cockpit usually has no shortage of. Now the iPad has to score some points for being self illuminating during those times when the sun is not flooding the cockpit with light, but can it illuminate itself with a dull red light, making the chart visible, without reversing the up to thirty minute process my eyes eyes have undergone to make the optimum adjustment to darkness. Again, a point for testing. Perhaps the robust case can include an anti-glare screen cover.
• You can write on a paper chart. The technique I was taught in low level mountain flying, and which I still use, despite all the augmentations of a terrain equipped GPS, is to mark with a pencil on the map where I am, and the time at each waypoint, so that if I ever get disoriented or discover I have taken the wrong valley, I have a track that tells me when and where I last knew where I was. Even without that particular navigational technique, it's useful to be able to write on paper. When the NOTAM says AMEND PUB, I'm supposed to actually amend the publication, to fix the incorrect frequency, the nav aid removed from service or the new restricted area. Does the electronic version support both 'pencil' (temporary, relevant to a limited number of journeys only) and 'ink' (permanent, to be retained until that chart is replaced) markings by the pilot? Done correctly, this could be a huge advantage for electronic: allowing markings to be searched, saved, scaled, and never obscuring map features. If Nav Canada would only update their NOTAM format (and I have faith that they will, someday) the NOTAMs could conceivably be applied directly to the electronic charts.
• You can set up a series of paper charts to show the important stages in your journey. Let's say I'm departing Edmonton, flying through a mountain pass to stay out of icing, and then heading into Vancouver. Before departure I set up the Edmonton VTA to show the western portion of the zone. I fold the Edmonton chart to centralize the area of the pass I will be negotiating, I have the enroute charts handy opened to the correct area, and i have the Vancouver VTA opened up so I can just grab it as I descend into their complex airspace, to know whom to talk to and where. I need to find out how to bookmark certain 'views' on the iPad, for the same effect. I will be disappointed if it cannot do that, but the iPad scores points for its ability to scroll continuously from one area to the next without my needing to dig in the box for the next chart.
• Paper is just paper, it can't do anything. A computer is a computer: it can compute. I imagine if I want to find Moose Creek airport I can do a search, rather than hunting all over the map for it, or looking up its lat-long in the CFS. If i want to know the distance and bearing from Moose Creek to Squirrel Pond, I expect the electronic product will draw a line on it for me, and tell me its bearing, distance and MEA. It would be nice if it could also line up the frequencies I should expect, but I'll be pleasantly surprised if it is that clever.
• I've already mastered paper's sneaky tricks. The most hilarious thing paper does when you're trying to use it is be hard to fold, and take over the entire cockpit, or rip. Approach plates don't change, zoom, or close when you poke them. If i put my finger on the MAP, will I change my view?

I was in the field for the meeting at which this purchase was decided, so I asked if it was intended to be supplemental or replace the paper charts. I got one answer (supplemental) from the ops manager and the opposite answer (replacing) from the pilot who I think is spearheading the project. So it's the old busted versus the new hotness. Any experience, tips, or features I've not thought of?

Late Spring

An airplane in Canada is legally required to be equipped with a working oil pressure gauge for each engine. When you start a piston engine, your eyes go to the oil pressure gauge. You're waiting for the pressure to come up. Given that it's the first thing you do on starting an engine, it's one of the first things I learned as a student. (Right after, "in order to start an engine, you have to turn the key to the start position and hold it there until the engine has actually started," which was explained to me immediately after I did it the wrong way. Yeah, I was pretty dense).  If the pressure doesn't come up, you're supposed to shut down the engine and not do anything else.

I'm not sure I've ever followed that instruction. I am starting an engine that I have just verified has oil in the crankcase and does not have a huge puddle of oil on the ground underneath. And I know how hot or cold that oil is, from 'so hot that I had to use a rag to handle the dipstick, and couldn't really see a level anyway', to 'I just spent twenty minutes deicing and I can't feel my toes or fingertips'. If it's the latter, yeah, I know that oil isn't going to come dancing through the tiny line to the pressure gauge in any big hurry. I will give the oil a while to warm up, and thus the oil pressure more time to increase.

In retrospect, I wonder if disciplining student eyes to go straight to the oil pressure gauge was a way of training us to be vigilant for a hot start when we move on to turbine engines.

High oil pressure can be a sign of a blockage, or you're running summer weight oil too far north, so instead of distributed cooling slipperiness, the oil is a viscous glob having trouble getting forced through some part of the system. Yeah, oil that is too thick can cause high or low oil pressure indication, because unless you're short on oil, both high and low oil pressure indications are caused by poor oil circulation. The pressure is high one place and low another place. Or it's the gauge. Low or high oil pressure, it's usually the gauge.

Even when its probably not the gauge, so long as there isn't oil splattered all over the airplane, and the engine didn't quit, the pilot rolls up to maintenance and says, "I have a low oil pressure indication, but it's probably just the gauge." You never want to give maintenance the idea that you are terrified of the airplane they gave you. I'm not sure why we do this. Perhaps I should try the opposite strategy sometimes and insist that ... oh wait I did that last week with a stuck propeller cable that turned out to be ... maybe I'll admit that one another time. While instantly diagnosable by someone leaning into the cockpit from the right-side door, it really wasn't visible to someone strapped into the left seat. Anyway, under-reporting of the severity of our concerns seems to be a pilot thing. Maybe because maintenance likes to show us to be wrong, so if we show little concern, they will work hard to find some way it could have killed us. Which is what we want them to do.

So my story is, I report unequal oil pressure on several consecutive flights in this airplane. It's in the green on both engines, I concede, but used to be equal, I think. I didn't remember there being a split, and I would. A pilot scans the engine instruments far more times than she knows, because we only notice we're doing it when something is wrong, and the two needles for the same thing on the two engines not being in the same position on their adjacent dials comes up as wrong, even when they are both in the green. The oil pressure indication on the right engine is inching up slowly. If it were a single engine airplane I probably would not notice. That's something I say a lot, but I keep reporting these things, because sometimes it matters. It's remarkable what a tiny thing can be a symptom of.


Eventually the needle reaches the yellow and they take it apart and find out what was wrong with it. An oil pressure gauge works the only way one logically could but I was still kind of flabbergasted when I realized that a little pressure line comes off the oil system, ducting a bit of the engine-pressure oil right to the instrument in my dashboard. Its internals consist partly of a ball bearing and a spring, and the pressure of the oil on the ball bearing compresses the spring, driving the needle.  The spring was worn out.

Good Thing We Weren't in Outer Space

I check the oxygen equipment and set up the oxygen bottle so I can reach the valve from my seat. The oxygen bottle has its own nylon pouch, which protects it from getting scratched or getting dirt in the valve, and the pouch has pockets for the instructions and accessories and straps for carrying it, so it's easy to secure the whole thing so it can't ricochet through the cabin in turbulence. Sometimes you just have a naked oxygen bottle and those are hard to confidently secure. I've also seen pilots just stick the whole thing in a seatback pocket, as if to say, "so long as I have oxygen it doesn't matter if I'm struck in the back of the head by a heavy object."

I run up the airplane. The altitude makes the engines run very rich. Once I am lined up on the runway, I even lean it a little for the take-off, just enough for it to run smoothly. The takeoff now seems to take forever in the thin, high altitude air. The afternoon is going to be hotter and make the air even thinner. That's why the runways are so long out here.

Climbing through 10,000' I try to turn the valve on, but I can't quite get it to work, damnit. I have to get the mission specialist to get it for me. I should have just left it on and controlled it from the little valve on the canula. I adjust that little valve now so the tiny indicator ball lines up with the gradation matching my altitude. I'm sucking oxygen through my nose, but it's hard to tell if it's working, because oxygen is odorless. I check my blood oxygen with a clip on meter.

The heat of the day drives cumulus development again. The same line of thunderstorms probably forms every day. The thunderheads don't seem as high as they do in the Canadian prairies, even though the tropopause is higher, so they are probably higher. I suppose it's because we are higher already, so there isn't as much vertical volume for them to build in. Below us are dry fields. I see something that the mission specialist says is a coal mine. It's an open mine, not the underground kind that they have in West Virginia, hence the lack of tragic news stories associated with midwest mining, the way there are in the east. That was a lazily constructed sentence, but I'm not fixing it, so there.

As I come in to land, I know what is going to happen and I work to compensate, but not quite enough to get it perfect. Although I am flying at the correct indicated airspeed into a very light wind, the countryside is racing by as if I had a horrific tailwind. The air is so thin that I need to go faster over the ground in order to fly through air at the same rate. It's like if you play the same Pac-Man game on a giant monitor, the little yellow guy seems to go twice as fast, even though he's getting the same number of dots. The illusion that I'm going fast makes me think I have more energy than I do. I should have done just a little flare and let the high groundspeed come off on the rollout, but instead I try to land just a touch too slowly and the touchdown is firm. "Sorry," I say, "Getting used to the altitude."

"We were going faster than usual, weren't we," says my critic from the back. Actually, I explain, we were going a touch slower than usual; it just looked faster, which is why I went too slowly and why it wasn't that great. He says he was looking at the GPS and it was faster. I'm not sure he believed my, "Faster groundspeed, yes, but slower airspeed," explanation. Next time how about I just not screw up.

The oxygen gauge is just on the edge of the red. I take the bottle and get in the passenger seat of the other mission specialist's truck to go to get an oxygen fill at the next airport over, while the afternoon pilot fuels and otherwise prepares for the next flight. It's about a twenty minute drive to the bigger airport. It has a couple of different names, because it's a regional airport as well as a local one, but it's well-signed and we find the FBO right away. I've used an FBO of this franchise before in another state. The customer waits outside in the air conditioned car, listening to satellite radio, while I go in with the oxygen bottle. There's another customer at the counter, so I wait and then make my request.

"Oh, sorry," she tells me cheerfully. "The A&P is the only one qualified to use the oxygen equipment and he goes home at one."

To be perfectly fair, when I called yesterday I asked if they provided oxygen service and then asked immediately what their hours were. I didn't specifically ask whether oxygen service was provided throughout their opening hours. But I think that was implied strongly enough that I have a right to be ticked. Rather than making her defuse an annoyed would-be customer I make her expend the same energy more usefully. Her place of business-- whether it was her or not on the phone last night I can't say--implied that I could get oxygen here yesterday, so she is going to figure out where I can get oxygen. I ask her to where I can get an oxygen fill on a Sunday, to call and confirm that I can really get O2 there, and when she doesn't get an answer at first, to see if she can call out the one guy who knows how to use the oxygen equipment, for a fee. She finds someone at the next airport along the road that is there and can fill the bottle. It's another forty-five minutes drive or so and then we have to come back with it. I thank her and get back in the truck to break the bad news.

It's not a bad drive, really. Air conditioned truck, compatible taste in music, fences, bluffs, cattle, authentic western scenery. Someone I know was going to be driving a motorhome up here, all the way from Indiana this month. If you pretend you came some place for a vacation you can usually make it into a fun adventure, and if it's so bad you couldn't imagine going there on purpose, you can at least thank your lucky stars you're not stupid enough to have gone there without being paid. We eventually get to the proper airport and find the FBO, which appears to be named "FBO." A flight instructor takes the bottle and looks at me strangely when I say that the previous airport said only the A&P could do it. Clearly he doesn't think this is a technical job. He brings it back. The gauge reads full. Presumably it will keep our sats up rather than making us talk in a squeaky voice. I pay for it and then get back in the truck for the long drive back.

There's an air conditioned pilot lounge at the airport, so my colleagues isn't baking out there on the ramp. The mission specialist drops me back at the hotel and then he goes flying.

Some idiot is buzzing the town in the evening while I'm trying to sleep. Over and over again. He's doing circuits, I guess what he as an American would call "staying in the pattern," but he's clearly not climbing out at an optimal rate after each takeoff. If I knew where you slept, bozo, I would buzz it at six tomorrow morning.

Dawson Something

After picking up a part in Regina, and stuffing it in the nose locker so it will be available wherever we are for the next maintenance, I'm going to Dawson Creek. That's Dawson Creek in Northern British Columbia, not to be confused with Dawson City in the Yukon, Dawson's Creek on the WB network, or just plain Dawson all over the place, including a crater on the moon. Yeah, not going to the moon this trip. The O2 bottle only holds about ten hours of supplemental oxygen. The CFS tells me that there are two aerodromes in town, but I am not going to accept dispatch to the one that has a 2000' sloped turf strip and is operated by the Flying L Ranch, so there's no need to call the client to confirm the landing site. The Flying L Ranch sounds like a cool place, but so does the main Dawson Creek airport. It has two separate prepared landing surfaces: one for landing on wheels and one for landing on floats. That is, there's a runway-shaped water-filled trench to the left of the main runway. There's no tower, but the mandatory frequency there is remoted to Peace River radio from 1330Z to 0530Z, which means that when I call, a guy in Alberta will answer.

Weather looks agreeable between hither and yon, despite a steep pressure gradient so I depart, with the addition of another crew member who happens to have been working in the area on his other job, making it an easy pick up. I'm not quite sure what happened to his vehicle. I know a pilot who can tell you off the top of her head how much it costs to ship a car by train from one part of the country to another. Others just own semi-abandoned cars in various places. There ought to be a special pilot car insurance rate for people who only get to use their cars when they aren't flying in another province.

The fuel number is listed in the CFS under "Military" for some reason. Maybe I misread it. They agreed to sell us fuel even though we carry no firearms or bombs, and came fairly quickly.

Dawson Creek is north and west of here. I flew and he manned the charts and radios. We passed fairly close to Saskatoon, so gave them a call to position report and update the weather. I initially just tuned the YXE ATIS for a local altimeter setting, but it was almost an hour out of date and it's always good to talk to someone en route; the FSS will volunteer SIGMETs and other hazards. We check the charts carefully looking for the new boundary between Edmonton and Winnipeg Radio before we call. We identify ourselves and position report, saying we are VFR between Regina and Dawson Creek. Our request is very standard "an altimeter setting and current weather at destination." We at first assume we have a Winnipegger on the line, as he had to ask for the ident of the reasonably large airport that is our destination, but then the conversation got weirder.

Us: It's Yankee Delta Quebec.

Him: Dawson Creek altimeter two nine nine three.

Us: [Silence]

Him: Did you want the rest of the weather?

Us: Yes please

Him: [reads entire METAR for YDQ]

Us: Thank you

Him: [Silence]

Us: [to each other] He's not going to give us a local altimeter setting?

We call back and ask for a local altimeter setting and he provides one. That probably doesn't sound weird to most people, but usually you can't talk to an FSS without being given at least one, and often a whole string of altimeter settings for the route ahead. An altimeter setting is the FSS version of "hello." It was especially relevant that day because of the rapid change in setting along our route. Newbie, I guess.

We could see we would clip the edge of Edmonton's control area. I gritted my teeth as I reached for the CFS, hoping that they weren't one of the zones that have started demanding advance codes for transit. I'm going to have to start making that a part of my VFR flight planning now. I look at where I'm going and where I'm coming from, but I am too often guilty of assuming that the old rules apply for VFR transit. Calgary, I learned the hard way, insists on an advance telephone call for a transponder code. Edmonton, fortunately, doesn't yet, but I promise to check each new edition of the CFS before each planned transit through their airspace. We looked up the appropriate frequency for Edmonton Terminal and let them know where we were and where we were going. No problem. They gave us a squawk code (and an altimeter setting) and cleared us through their airspace. We saw three different airports we've worked out of in the last year or so and then we passed out of their airspace to the north and they cleared us en route to squawk VFR. And updated our altimeter setting.

I was flying at 6500', a VFR altitude appropriate for going west, high enough to be out of the daytime turbulence but not so high as to require oxygen or turning on the heater. As I continued east a layer of daytime cumulus cloud was starting to form, building to just about my level. I dodged a few, and then as the layer thickened, mused about my choice, "Up or down? the eternal question." Down would put me into more turbulence, closer to control zones and terrain. Up requires me to increase the power for the climb and then readjust everything again, and the cumulus tops will build another couple of thousand feet before destination, requiring me to do it all over again. Pilots, if you haven't gathered already, can be really lazy. You want me to move levers? It's not a really difficult choice, just a topic of conversation. Pilots can be hard up for those, too. I got a new altimeter setting form flight services. It is higher, good news weatherwise, but putting in a higher altimeter setting shows me at a higher indicated altitude. If I descend again to an indicated 6500' feet I'll really be in the cloud tops. So I take the head start and climb to 8500'.

This works fine for a while, and then the clouds, as predicted, build back to my level. By this time I'm in the vicinity of Grande Prairie. We won't be in their zone, but call them for traffic advisories anyway. Their new altimeter setting puts me back in the tops again, so I descend back to 6500', which is now cloud-free, thanks to the fact that cloud bases tend to gradually rise during the day, and that my new 6500' is a few hundred feet below my old 6500', thanks to the rising pressure. People who have blindly memorized "from high to low, look out below" without close regard for the underlying physics may need to stop and ponder that for a moment. We report the altitude change and call clear as we continue to the west. They thank us for checking in. It's good when towers do that. Sometimes pilots are ambivalent about calling an air traffic agency we don't have to, and when the controlling agency's response sounds like we've bothered them or that they couldn't care less, it results in subtle pilot behaviour modification. But every one who acknowledges the utility of just knowing there's an airplane out there beyond their sphere of control reinforces our motivation to call.

Now we're almost at Dawson Creek. We call the FSS and the guy in Peace River answers us, as advertised. He can't see the traffic out here in BC, but he keeps track of it. There's someone in a single departing, something else small and slow arriving, shouldn't be any conflicts. Then a medevac faster than us checks in behind us. We're almost overhead and hear a five miles out call. Is this going to work out? Oh phew that five mile call was the slow, departing traffic, not the incoming medevac. We land, after jokingly lining up on the water runway for a photo op, then call clear and taxi for fuel.

It's a more civilized-looking airport than we expected. It has a classy new passenger terminal with a big yellow "secure area" square painted on the apron outside of it, a little tower building (probably vacant, seeing as the radio service is remoted to Alberta) and lots of paved apron. There are two fuel pumps either side of a sign that gives prices (good prices, too) for avgas and jet, but while the right tank has a Jet A sticker on it, there is no avgas marking on the left tank. Weird. The paper cover of the journey log tears on the seat pocket as we take it out to record the flight. Grr. I always buy the hardcover version when I have a choice. But they keep replacing this one before it's full, dunno why.

We unload the airplane and I give the receipts for the ferry fuel to the customer: they are responsible for that. The Regina receipt is just a truck fuel ticket, not a credit card receipt, because the truck driver didn't process the credit card, just called in the information. Client needs a proper receipt. I didn't bring a CFS in from the plane, but the fuel number is in the recently called list in my phone. They fax a copy of the credit card receipt and everyone is happy.

Dinner is at some chain restaurant where they casually offer you garlic bread with your entree, then charge you $3.50 for it. One slice.

I did get a chance to call the airline captain who was one of the first to encourage me in all this. As I was approaching Regina, he had been just leaving, ferrying a smaller airplane in the other direction. I believe that brings his home collection of aircraft to five. He's well, just retired, still happily married to his original wife, and having a great time. I'll see if I can get out to see him when work and other aspects of life let up around ... January I think.

Condolences to Poland

I've been busy flying the last couple of days but have an evening off right now, and the opportunity to read about and interject some comments on the recent tragedy in Smolensk. On April 10th a Tupolev jet carrying 96 people, including Polish President Lech Kaczynski, crashed on approach to the Smolensk Airport in Russia, killing all aboard, the political, cultural and military elite of Poland. News reports indicate that the pilot made multiple missed approaches to to the fog-bound airport, and continued the final approach despite an altitude warning from air traffic control.

More disturbingly, the same story relates an earlier incident where President Kaczynski threatened a pilot with "consequences" when he diverted to Azerbaijan instead of landing in unsuitable conditions. That's a factor of company culture that a good investigation may have to address during the investigation. I don't have a problem with the pilot of an aircraft consulting the passengers regarding their wishes after a missed approach. Would they prefer to land as near as possible and seek ground transport to the original destination or to return home? Would they prefer to try another approach and then have to land elsewhere to refuel before returning home, or to return home in one shot? Sometimes passengers mistake this input for having the final decision, but as former president Lech Walesa recalled, "Sometimes the plane captain would make the decision himself, even against the recommendations." The captain should always be making the decision, considering passenger recommendations only after safety is assured. The fact that a Russian-built airplane crashed in Russia, to be investigated by the Russians, brings out the Polish conspiracy theorists, but while I'd totally read that espionage novel, I don't believe it is more than fiction. As Walesa also said, "We do not yet know what happened, so let’s leave the explaining to the experts."

It's not only an aviation tragedy, but a national tragedy. Poland is an ancient country with a long history of strong leadership and culture, but no country can easily absorb the sudden simultaneous loss of its leaders in multiple fields of endeavour. The terrible irony of the situation is that those on board were on their way to a memorial service for a previous generation of Polish leaders and intellectuals who were massacred by the Soviets in Katyn Forest. Approximately twenty-two thousand Poles, such as military officers, professors, lawyers, public servants, priests and other officials were executed there. It's similar to the purges Stalin carried out within the Soviet Union itself; if you remove the intelligentsia--the people capable of understanding, caring about and communicating what is wrong with your regime--then it is much easier to lead the remaining citizenry. Anyone who would otherwise interfere with your power is either dead, imprisoned or terrified.

My condolences to the families and countrymen of all those involved. I trust that Poland will find talented people to take up the reins and continue its national journey. Poland has not yet succumbed.

Q.E.D.

A commenter recently asked about the altimeter setting and Q-codes. I have probably blogged on this before, but Blogspot doesn't show it in my archives so it's just as easy to explain again. It is to do with the way the altimeter works.

The instrument in the panel that indicates my altitude is a barometric altimeter. It operates purely by air pressure, mechanically comparing the pressure in its sealed reference capsules to the air pressure sensed immediately outside the airplane. For this purpose there are little holes on the outside of my fuselage called static ports, and tubes conduct the pressure from the static ports up to the altimeters.

As the airplane climbs, the outside air pressure drops, but the pressure inside the reference capsules stays the same and this difference moves the hands around the face of the clocklike altimeter to indicate my altitude. Electronic altimeters work the same way, except that the pressure difference is converted to a digital signal. All the altimeter knows is the difference in pressure. If the pressure goes up, the needles show a lower altitude. If the pressure goes down, the needles show a higher altitude. This also happens without the airplane ever leaving the ground, just because the air pressure changes as weather systems move through.

In order to always start at a known place, there's a knob on the altimeter that moves what the altimeter considers to be the zero altitude up or down. So you could be on the ground with the altimeter reading zero, and turn the knob so that the altimeter read a thousand feet, and then crank it back the other way so the altimeter read two hundred feet below sea level. While you turn the knob, and the altimeter hands are moving, a small dial with numbers is also moving, visible through a cutout in the face of the altimeter. On an North American altimeter the numbers usually range from 28.10 to 31.00. On a European altimeter they range from about 950 to 1050. (International altimeters have two windows and two dials driven by the same knob). Turn the knob so a bigger number appears in the window and the hands go up to indicate a higher altitude. Select a lower number in the Kollsman window and the hands point to a lower altitude. Whee! The pilot will have to set it correctly before takeoff.

But what is correctly? There are actually two systems as to what the altimeter should read when you're parked. One is that it should read zero when you're on the ground, no matter where that ground is. Under that system, a circuit pattern flown at a thousand feet above ground level would always read 1000' on the altimeter, regardless of the elevation of the airport. If the altimeter reads two hundred feet, you're two hundred feet above ground. The number that you would set in the Kollsman window to make the altimeter read zero on the ground at a particular airport is called the QFE for that airport. The QFE system is not very popular. I believe the British military uses it, as does Russia, so probably much of the former Eastern bloc. I highly doubt that a Canadian or American controller would be able to give you a QFE if you asked for one, and many probably would not understand the question. Even if you could get the QFE, there are many airports in the US where you couldn't set it on an ordinary altimeter, because the numbers in the Kollsman window don't go that high.

The far more popular way to set an altimeter is using the QNH, but North American pilots don't learn that term, either. We just call it "the altimeter setting." The altimeter setting is the number you set in the Kollsman window so that the altimeter shows airport elevation while you are on the ground. If the airport is 1200' above sea level, then the altimeter shows 1200' when you're parked, and 2200' when you're in a thousand foot circuit pattern.

Neither the QFE nor the QNH for a particular airport is fixed. It varies from hour to hour with the weather patterns. That's why the controllers and the ATIS broadcast the altimeter setting.

There's a third way to set your altimeter, which everyone does one they climb into the flight levels. That is to set 29.92 and leave it, so that you don't have to keep changing it as you go through different pressure systems en route. If there's a Q-code describing this setting I don't know it. We call it "twenty-nine nine two."

Update: The terse and anonymous first commenter below has indicated that twenty-nine nine two is called QNE. And in verifying that, I'm reminded that with 29.92 set on my altimeter, it is showing the pressure altitude but most people don't call it "setting the pressure altitude" unless they are doing it momentarily for the purpose of determining the pressure altitude for a calculation.

Too Much Information

Pursuant to yesterday's non-adventure of the missing pilot, my first order of business today was to replace my cellphone with one that works in BC. The choice was Telus (shouldn't that be TelCan?) or Bell. In an attempt to demonstrate to the clients that I am taking prompt and immediate action to address the problem, I take their recommendation and walk across the Alaska Highway (a.k.a. 50th Avenue, if you hadn't guessed) to go to the Telus store.

This was going to be an entire post about buying a cellphone, but comments on the previous post show that you can all predict how that goes. There's the phone itself, with the possibility of cameras, video games, holographi projectors and laser death rays, when what I am really looking for is good predictive text messaging software and buttons that won't wear out quickly. There's the option of pay as you go, versus contract (and you can't swap between these, because they involve different telephones. Pay as you go is ludicrously expensive (how about 55 cents a minute for nationwide long distance?) The contract probably isn't much better when I consider that I have to pay for it in months when I'm not using that telephone. And the contracts are complex with plans and add-ons that I kind of need but aren't really appropriate to the way I use the phone. And of course there is the difficulty of getting a phone number that won't be long distance when I'm at home. I grumble, then suck it up, acknowledging apologetically to the young women working at the store that overpriced Canadian cell service is not their fault. I buy the phone, sign the contract, memorize my new number, and go back to the hotel. That's enough about that. I'll give you too much information about something else.

Here I am flying the airplane. It's ten thirty, two and a half hours into a seven hour flight, and my body has just reminded me that I forgot to pee before takeoff. It's part of my routine, but I didn't have to "go" then, and was busy folding wing tents or something, right up to departure. It's not killing me yet, but there are four and a half hours left before I'll be on the ground. There's nowhere convenient to land, and even if I were passing directly over an airport, I can't just say, "ladies and gentlemen, we now have an unscheduled stop because the pilot didn't learn a lesson her mother should have taught her by the time she was four." Always go before you go.

Last time I ordered oxygen cannulas I topped up the order with a package of disposable portable urinals that are supposed to be effective for men and women. They have a powder in them that turns to a gel when wet, so they can't spill. I included their presence in my passenger briefing and one passenger, a male, confirmed that the product worked. I should have tucked one in my flight bag, but I left them all the airplane, and I'm not in that airplane now. After another hour or so has passsed, I'm furtively looking around the cockpit for a container. I'm not picky. Funnel plus hose plus window seems like a really good idea right now. There's nothing.

It's hard to do the pee-pee dance while flying an airplane. You just have to take your mind off it. I manage to make the urge go away for a while, but the duration of that while subsides to nothing by the end of the flight. And there's a chain reaction. I want to minimize the amount of water I drink, because that will exacerbate the situation, but of course I don't want to spend hours without water. And I'm hungry, but it takes water to digest food, especially the energy bars that I fly with, so I have to limit food, too. So now I'm hungry, a little bit thirsty and floating on my own distended bladder. I somehow survive the flight, turn in a surprisingly good landing, and rush through engine-off checks. The fueller meets the flight at shutdown and I almost knock her over on the way to the washroom.

The next day I completely wring out my bladder before the eight a.m. takeoff. I'm not going through that again! Ten o' clock and all is well ... 10:15 ... 10:30. Oh oh. Same problem. Hey! What's going here? Have I lost my touch. Did I break something by holding it so hard yesterday? Can you do permanent damage by holding your pee? There's a Seinfeld episode about that. I endure another excruciating flight. I think having to pee sits above several levels of pain in the scale of impediments to conentration and enjoyment. In fact, I can vouch for that, having attended a ground school course with a broken back. I survive that flight too, and hit the internet for information.

First off, anyone who hits the comments and tells me, perhaps citing Tycho Brahe, that people have died from holding their pee, are full of it. (But not as full as I was). The sphincter concerned is going to let loose and wet the left seat long before it explodes out any other avenue. Like anything else on the Internet, I get a mixed set of results. The first batch of hits I get are with reference to children, and they promise dire consequences from forcing children to hold it.

"Infrequent urination and incomplete emptying lead to an ever-increasing bladder size and capacity. This is turn leads to a decrease in sensation to empty the bladder... Renal failure may ultimately develop secondary to bladder function abnormalities" (MedHelp.org, Urology Forum).

This one says that if the bladder gets too full urine can back up into the kidneys causing extra pressure which may damage the tiny blood vessels in the kidney.

Over time, the pressure can cause the bladder muscles to become very thick and the bladder may generate frequent, strong contractions... The high pressures in the bladder may force urine backwards (reflux) up the tubes (ureters) from the kidneys and damage the kidneys." (Christopher S. Cooper, M.D., 2000, Pediatric Urologist).

I'm guessing there's a difference between adults and children, and that part of the maturing process that allows us to understand the urges that allow us to be toilet trained in the first place is a change in our bodies that allows us to hold it.

There are a lot of medical-sounding hits that indicate holding your pee is in itself not a bad thing, but that if you have a urinary infection that delayed urination can spread the infection to the kidneys.

On the other side of the issue, the admitedly amateur WikiHow Says there's no medical impact of holding it in, and gives suggestions on how to hold it.

I wonder also if this is a sex-specific question, as my anatomy doesn't quite match that of those who are warned of possible protate problems.

At any rate I didn't break anything vital, as subsequent flights went fine and my bladder allowed me to eat and drink, land the plane, put on the engine tents and wing covers and then find the washroom.

I wonder where NASA gets their famous astronaut diapers? Anyone know? Maybe I'll write them.

P-I-C Responsibility

This has been kicking around in my drafts folder for a while and an entry on a new-to-me blog gives me reason to finish it. If there is more than one pilot assigned to a flight, one of them is designated pilot-in-command. As pilot-in-command you are given latitude to make decisions. That's what it's about. There is air law to follow, plus you are given a number of manuals and data to help you make those decisions, but most of them, even the laws, give considerable latitude for a pilot to do what is safe in a particular case.

It's not so much that you are required to follow every manual. It's that you are required to not screw up. You can find justification for almost any action in the manual, but so can the company find condemnation. I can honestly never think of an occasion where a colleague got in trouble for violating a rule when no harm (i.e. regulatory action, aircraft damage, complaint, or harm to public image) was done. Right up until it isn't done well, pilots get praised for their ability to land in stiff crosswinds. That's getting the job done.

That's why the captain is paid significantly more than the FO. The captain is the one who approves or vetoes such a decision, whether she is the one at the controls or not. As PIC you know that if you go off the end of the runway, chew up the props, run out of fuel, damage something with jet blast, blow a tire, ding a wingtip, incur a noise complaint, arrive late, divert, or annoy a customer, questions will be asked. If there's an accident, the relevant authorities will go over everything you did with reference to the laws, the SOPs, the AFM, the FDR, the CVR, the instructions given by ATC, the weather, the NOTAMs, the charts and every other recording and piece of paper they can find. And if they find a recommendation or a policy or a memo that you were not following to the letter, you are screwed.

If something beyond your control goes spectacularly wrong, like the gear lever has been moved to the down position, but one of the wheels won't lock down, you're not blamed specifically for that, although you might be accused of not spotting some damage on the preflight inspection.

I can't remember where I grabbed this exchange from. A movie? A TV show?

"You think you have all the answers."

"I'm the captain. That's my job."

Often I think the first officer's job is even harder, and this story (told on someone else's blog) illustrates that well. Of course Sulako beat me to the punch, but I still wanted to link to it. The story was originally on her personal blog and the traffic from here was more than she wanted, so I've taken out the link. See her medevac stories here. Ensuring a safe flight is the responsibility of both pilots, but the no-go decision is harder for the FO. If the FO wants to go, but the captain says "we're not continuing, the ice is too bad," the FO can say, "oh, I didn't think it was that bad," or even "you're a chicken," (with a smile) but has no reason to argue. The FO might be a bit embarrassed and vow to be more diligent at checking the weather next time. But no one really loses face.

Now let it be the captain who wants to go when the FO says the conditions are not suitable. The FO may have to fight for her life to alter that decision. Had there been passengers and injury or death involved in this flight, as there have been in so many before and after it, Dagny would probably have been exonerated. She repeatedly and strenuously objected to the captain's decisions, and finally did override them. But many first officers who have been placed in that position have no descendants. I hope Dagny gets to tell this story to her kids, to teach them to stand up for what they believe in.

Oh and a straw poll: I say "Pee Eye See" but I've heard people refer to "pick-time" in their logbooks. If you are a pilot, please tell me how you pronounce PIC.

Hot Air Rises

In order to continue explaining air masses I must first explain density and pressure. Density is a measurement of how close together the air molecules are, or, put another way, a measure of what weight of air exists in any given volume. More weight per volume is the same thing as higher density.

If you pack socks into a box there are two ways to maximize the sock density. One is to use thin, non-fluffy socks and the other is to cram your socks in as hard as you can, stomping on them to get them to fit before you seal the box. (You know I just moved house, right?) These two factors are the same as the ones that affect air density.

'Fluffiness' of the air corresponds of temperature. The higher the temperature, the greater the volume the air wants to occupy. It's actually because the speed of the air molecules is greater at high temperature, but you can think of the volume they thus occupy as them being all fluffed up hot out of the tumble drier. All else being equal, warm air occupies more volume than the same weight of cold air. Therefore, all else being equal, an equivalent volume of cold air weighs more than warm air.

Stomping on the pile of socks corresponds to pressure. Is pressure, really. Pressure is defined as force per unit area, and in the atmosphere it is a result of all the air stacked up on top of the bit of air you're considering. Imagine you're looking at a cubic litre of air(*). Its pressure is equivalent to the weight of all the ten by ten by ten cubes of air that are stacked on top of it, all the way up to the top of the atmosphere. Sure, one little cube of air doesn't weigh much, but stack enough up and it adds up. So air down near the bottom of the atmosphere is at a higher pressure than air further up in the atmosphere, where it has fewer boxes stacked on top of it. Kind of like the box of drinking glasses underneath four boxes of aviation textbooks is under more pressure than the one that is ony one box into a pile.

You can see pressure and temperature kind of work against one another with respect to density. If the pressure increases and the temperture stays the same, the density will increase. If the temperature increases and the pressure stays the same, the density will decrease. Cold air at a high altitude is less dense than warm air at a low altitude, because the effect of the low pressure at high altitude more than balances the effect of the temperature difference. There's even a formula:
  P x V = T x constant
P = pressure, T = temperature, V = volume.

So, we have a bunch of air hanging about. Air in the same vicinity within the same air mass is pretty much interchangeable. It's all mostly nitrogen, and contains some amount of moisture, and at the same pressure because its under the same pile of air. And its at the same temperature. If some of it were to be heated up to be warmer than the surrounding air, look at what would happen. Firstly, it doesn't warm the air around it. If air were good at sharing its heat with the molecules around it, down-filled parkas wouldn't be such treasured possessions in the north. (The puffy feathers create little air pockets and heat doesn't travel well through air, so that keeps me warm.) If a little bit of air is warmer than the air around it then it is also less dense than the air around it. And that means that the gravitational force holding it down isn't as great as the pressure differential between the air above it and the air below it, so it is pushed up, and rises.

And yes, I did just spend six paragraphs explaining that hot air rises. Just think of it as a demonstration of hot air. The reason I did it that way is that warm air doesn't always rise. If that were true it would be warmer at the tops of mountains than at the bottom. Air rises if it is less dense than the air around it. If the pressure is the same, then temperature determines density. So it rises if it is warmer than the air around it, sinks if it is colder than the air around it, and stays in the same place if it is the same temperature as the air around it.

There's one further trick to the rising air, as it rises, the pressure around it decreases, so according to the formula, if the temperature stays the same, the volume has to increase. And it does. The rising air expands. It actually also cools as it expands, so the result is that the same air occupies a greater volume at a lower pressure and temperature.

What it does next is for next time this multi-threaded blog returns to weather theory.

(*)If you didn't go to elementary school in Canada after metrification you missed out on carefully measuring ten centimetres by ten centimetres by ten centimetres and building a little cardboard box. That's about four inches cubed, for the aggressively non-metric. Once you'd built and folded your cardboard cube, and mended any measuring or folding errors with vast quantities of cellophane tape, you had a concrete way to visualize a ten centimetre length, one thousand cubic centimetres, one litre capacity, and, if you imagined what your cube would feel like if it were filled with water, one kilogram. I'm not making this up. They used to hand these things out at fairgrounds, in modern 1970s colours like pink, yellow and lime green. Someone back me up here. I'll trade you a working flashlight for a genuine 1970s MetriCube.