Thursday, November 19, 2015

Pilots and Birds

Pilots have sort of a love-hate relationship with birds. Some learned to fly out of a desire to be like the birds. I came grudgingly to appreciate avian skills while I was a student pilot learning to judge winds and momentum in the flare. I still derive schadenfreude from watching a bird misjudge a crosswind landing, because they usually get it so perfect, angling their wings and tail and settling on a single branch just as groundspeed and vertical speed reach zero. I knew an ultralight pilot whose pinnacle of life experience occurred the day an eagle flew along wingtip-to-wingtip with his tiny craft, checking him out and then seeming to just share the joy of being aloft on a beautiful day. If you've got through any part of a career in aviation without having to reject a take-off, perform a go-around, declare an emergency, or visit maintenance because of birds, then I can't imagine which part of the planet you fly over.

The airplane I flew yesterday bears a scar that we think is a rat strike. I know that a rat is not a bird, but I still blame a bird. See, one day an eagle crossed our path while we were on the take-off roll. There was no thump and no exploding cloud of feathers, so we were pretty sure we hadn't struck the eagle, but after the flight there was nevertheless a small dent, mostly just stretching of the aluminum skin between two ribs on the wing, and some blood spatters. The airport crew reported finding no carcass, and certainly an eagle would have made a bigger dent. Our theory is that the eagle dropped its payload in order to more easily dodge us. I should have gone full CSI on the remains. I'll bet I could have found some fibres and checked them out at the MicrolabNW Photomicrograph Gallery. As it is I just nag maintenance to put the dent repair on their spare time list, because tiny as the dent is, it is a roughness in the wing, and that spot is always the first one to ice up in flight.

The video below (preceded by an ad, you don't lose anything if you just mute the whole video) is from an incident a year ago when a bird strike smashed the spinner on a Dash-8 on take-off. I don't see any damage to the propeller itself, but the damage to the spinner must have caused an imbalance, because the pilots elected to shut the engine down. You can see the blades feathered (aligned with the direction of flight for minimum air resistance). And I have to laugh at the fact that the very terminology "feathered" is bird-related.

They inspired us to fly in the first place. They interfere every day with our ability to do so safely. We can't stop admiring them and we can't stop resenting them. This whole post has just been an excuse to show you this gif. Does anyone not love this crow? It's just a looped gif, but the full YouTube clip shows that it wasn't an accident. That crow was hanging in there for the ride. I suppose it wasn't all that different to clinging to a branch on a windy day, but it's having fun, isn't it?

Thursday, November 12, 2015

Why Helicopters Work That Way

I've never studied helicopter aerodynamics, but I witnessed a helicopter crash once, and the event was consistent with the theory that it's principally the integrity of the tail rotor that prevents the helicopter from behaving the way the bluebird expects, but the chicken has an excellent point.

2 Cows and a Chicken Comic Strip on

Also as the days get darker and the weather outside arbitrary northern hotels gets bleaker, I'm tending to agree with these chickens.

Currently binging on House, Grey's Anatomy, Community, and Fringe.

Thursday, November 05, 2015

Logbook Strategy

I finally got my logbook up-to-date, every flight entered, every page totalled, grand total calculated. Each line represents one flight, and includes the date, aircraft type, aircraft registration, point of origin, destination, crew, and duration of the flight. There's also a remarks field which I sometimes use to include information like "annual review," "hit an eagle at rotation," "picking up new airplane," or "ferry permit with u/s flaps." Long ago I used to write my first initial and full last name in the pilot in command or copilot field, as appropriate, but that got tiring and sometime over the last couple of logbooks ago I switched to "self" and then "me," with the other crewmembers reduced to initials after the first few entries with their complete names.

The duration blank for each flight is not a single column, but eighteen columns, the whole facing page, in all appropriate combinations of single- and multi-engine time, night and day, pilot-in-command, dual instruction, and copilot, plus additional columns to record time in instrument meteorological conditions (clouds), simulated IMC, and in a flight simulator. For the last seven years I have used two columns: multi-engine day PIC and multi-engine night PIC. I'm even pilot-in-command for my annual training flights, because we hire outside experts who aren't ensured on our aircraft. So on every page I complete there are only two columns I need to total, multi-PIC-day and multi-PIC-night. I sometimes fill in numbers for IMC, or landings, but long, long ago stopped totalling them. There are a even a couple of do-it-yourself columns in which I sometimes track time on floats, turbine vs. piston or tailwheel. I tried to persuade myself to stop carrying forward the times in the columns other than the two that actually get updated every page, unless for some reason I flew a single-engine aircraft or acted as co-pilot, but despite being lazy enough not to update my logbook for three years, once I started updating, I felt obligated to carry those stupid numbers forward, page after page. According to the numbers, at some point in my career I acted as a copilot at night. I can't even think when that was, as the two-crew aircraft in which I logged my copilot time was a day-only operation. I think I must have been acting as co-pilot for new captain. But I'm copying forward that 2.0 every time I turn the page. Also the 13.1 night dual single engine. I have this minor fantasy of renting a single-engine aircraft and flying just long enough, day, night, PIC, and dual, in order to bring all my logged hours up to even numbers. The trickiest part about copying the numbers forward though, is making them fit in the boxes.

Both my single- and multi-engine daytime hours extend to five digits, including the one after the decimal point, and the boxes allocated for the totals are not very big. There are a few possible strategies for coping with this. I generally used a fine-tipped pen and very small printing, but depending on how many 4s, 6s and other digits that don't compress well there are in the total, sometimes I combine this with writing the number diagonally from corner to corner of the tiny box, or writing the decimal point and final digit on a second line. Sometimes I just give up and write the total in the bottom margin, with an arrow pointing into the box it should occupy. I suspect most of you with this kind of time don't bother keeping a personal logbook at all, just hand the paperwork that shows you're legal into company, and then at medical time just add what you've flown in the past year onto whatever total you gave the year before. That's what I've done for the last three years. The real timekeepers among you will be using an electronic logbook that, at a couple of button presses, can extract all your multi-engine turbine time flown on a Tuesday. But I can't be the lone holdout Luddite enough to be still using paper logbooks, but having trouble fitting the big numbers on the page. What's your preferred strategy?

Sunday, November 01, 2015

Partial Research is Funnier than None

At 1:35:14 of the movie The Bourne Identity, there's an airplane. It's not important to the plot, just a brief scene to show that Important Serious Guy is going to Paris. It only merited a second glance because Important Serious Guy was going to take the "first flight out" which usually refers to scheduled flights, yet the airplane in question is a Dassault Falcon 900 and the passenger is driven up to the boarding stairs in a limo. It's clearly a private flight. So in between writing the dialogue and getting the location, someone decided that the secret agent guy wasn't going to fly airline, or it was just cheaper for the production to get the plane and the location for one guy boarding a small jet than to arrange a whole airline cabin set, and they missed changing the actor's line. I can even accept that by "first flight" the guy meant, "as soon as the pilots have the airplane ready," and that there's nothing wrong with the dialogue.

It's a three-engine jet, which is kind of cool. Wikipedia tells me that it and the Falcon 7X are the only trijets still in production. On the nacelle of the centre engine we see the aircraft registration N-GIDE. I can't say whether it was the oddity of an N-number followed by a dash and four letters that drew my attention to the fact that the N has clearly been stuck on as a patch, or vice versa, but that is one silly aircraft registration. It took me three guesses to find it as French-registered F-GIDE a Dassault Falcon 900 currently owned by GE Capital Equipement Finance, and based in Paris. The airplane looked like this in 1998, which doesn't match the movie, but the 1998 paint job looks like my high school locker room, so I'm not surprised it would be changed. I'm imagining someone has scouted the location, paid whatever is the going rate is for using someone's airplane as a set for a couple of hours, and got airport permission to drive their limo and camera trucks and whatever around the apron. They put an actor in the cockpit--just one, we'll presume that the other pilot is in the back to greet the passenger--and generally tried to make it look as though it's a US government airplane ready to take this guy to Paris. They slapped a US flag decal on it, by the boarding door, and then someone did just enough research to get in trouble. I think the location manager spotted the F starting the registration and realized that that represented France. They somehow learned that American aircraft registrations start with N, without realizing that they don't have a dash, and they have numbers in them. To me the result is as adorable as a kid trying to hide by covering her eyes: that act of concealment draws more attention than none at all, but it shows that they tried. Had they tried harder, they would have discovered that the FAA reserves the tail numbers N88892, N9748C, and N9747P for use in movies and television, and then I never would have noticed. Probably I wouldn't have noticed if they had left the French registration intact, either. I'm sure the US government leases aircraft in more exotic places than France.

Given that it's the same kind of half-completed research I do all the time for my blog, and will definitely be doing for this year's NaNoWriMo novel, starting today, I hope I'm not alone in getting enjoyment from the funny.

Thursday, October 29, 2015

The Wrong Trousers

On my first job with a uniform, I was required to wear black pants and a white pilot shirt. That's a pretty standard outfit, and a lot of companies just leave it to the pilot to obtain those articles of clothing. That first company didn't pay much, so I just wore whatever black pants kind of fit me at the second-hand store. Another company sent me to Mark's Work Wearhouse to buy a particular style. I think they wanted beige, but the style number was a men's style, so I spent half an hour or so trying to find the women's style that looked the most like the men's style, yet still fit me. I don't remember how that worked out. At a later company I actually did wear a men's style because I could get far better quality for the same price, and while the fit at the hips was not stellar, at least the legs were long enough, the pockets actually able to hold things, and they didn't have little cutesy buckles or offer tummy control or butt enhancement. Seriously, if you've never bought women's pants, you'd be amazed by what they claim to do. Stupid things had to be dry-cleaned though, and I'm pretty sure they were flammable.

In my job I have to crawl, literally crawl on my hands and knees, under aircraft. I have to lug things against my legs. I sometimes wipe oily hands on my pants (not my underwear, British readers). I sit on my butt for five or six hours at a time. I occasionally need to wear thermal underwear under my clothes. I want pants that are black, cotton, durable, and machine washable. They need to be comfortable, not too tight, but not so loose that you're going to see my underwear as I crawl under the plane. Not that I care all that much about that last one. I always figure if you're hard up enough that seeing a pilot's underwear is going to do it for you, then I can throw you that one for free.

After a while I settled on a style at Mark's Work Wearhouse. I would buy several pairs at a time, making them ship extra ones in from elsewhere to fulfill my order. A couple of years ago they stopped selling them. It wasn't just that they'd changed the style, they no longer sold a medium duty woman's work pant. They had the really heavy duty ones, not something I wanted to sit for hours wearing, and they had yoga pants and dress pants. So last year I carefully measured myself according to the instructions on the website, and ordered a few different styles from Dickies, all of which arrived big enough for two of me. I sent them back and ordered four more that fit me about as well as the ones from the second-hand store, but by this point the old ones that fit me well all had patches on them, so I kept and wore the ill-fitting ones. Now I have a collection of badly-fitting black pants some of which have holes in them.

Today I tried to buy more pants. I finally gave up when a link for women's work pants took me to a page where not only were all the pants too short for the actual models, but the models were all wearing high heels. I guess "working women" need work pants too. I'll have to go back to men's styles.

Friday, October 23, 2015

Oxygen Exchange

I work in an unpressurized aircraft at altitudes where the atmospheric pressure is low enough that oxygen is required. Between 10,000' and F180 (about 18,000') I wear a nasal cannula: an arrangement of tubes, including two blowing oxygen up my up my nostrils. Above FL180 I wear a mask that covers my nose and mouth. I could skip the cannula and wear the mask any time I was above 10,000' but I can't eat or drink while wearing it, so it gets old fast. Plus the design of the cannula is such that it recycles exhaled oxygen, meaning that the oxygen supply lasts a lot longer on cannulas. Thus we only use the masks if we're working above 18,000'.

Putting the mask on involves taking off my headset, putting the mask over my face, pulling the head strap into place, putting the headset back on, and fastening another mask strap behind my neck. Finally I have to swap the microphone plug for the headset boom mike with the microphone plug for the in-mask mic. I can do all this before take-off, which I will if I'm in busy airspace. I started up next to a military jet once and noticed its pilot put on his oxygen mask before start up. If I am in uncontrolled airspace, I typically put my mask on just before I climb through 10,000'. If I'm expected to be monitoring a frequency, I wait until a needy or slow-talking pilot starts to make a call irrelevant to me, and then I can get the headset off, mask on, and headset back on before the call is over, ensuring I don't miss any calls. It takes less than thirty seconds. On descent, I can use the same technique, or just leave it on until I park, likely confusing the FBO marshallers.

Sometimes the day starts out with an hour of work at at 20,000' and then progresses to three more at 15,000'. Obviously I need the mask for the high level work, but would prefer to be able to eat and drink for the rest of the flight. In this case the swap involves all of the above, plus disconnecting the mask from the oxygen receptacle, connecting the cannula, and putting the cannula in my nostrils. It looks just like the cannulas the patients in House wear, but rather than looping around my ears and hanging down in front, it just goes around my head, held up by my headset earcups, and secured in place with a baseball cap. The point of this post is that I think about perfecting the swap between oxygen supplies at altitude. Should I breathe normally, or hold my breath during the swap?

The way breathing works is that the partial pressure in the air I inhale is greater than that in the lung capillaries it is in contact with. The imbalance causes oxygen to diffuse into the capillary, until the partial pressures are equal, the way any gas does across any membrane. So if the partial pressure in the ambient air is less than that of my lung capillaries, the act of breathing will actually decrease the oxygen level in my blood, and it would be better to hold my breath while I switch between mask and cannula.

The partial pressure of oxygen in ambient air at sea level is 21% of 29.92 inches of mercury, which is 6.28 inches of mercury. I'm going to convert that 160 mm Hg, not because I'm obsessed with metric, but because Wikipedia gives me biological numbers in millimetres of mercury so I have to convert one of them in order to do the math. At 18,000' the partial pressure of oxygen in the ambient air is half that at sea level, so 80 mm Hg. The partial pressure of oxygen in lung capillaries at sea level is 20-40 mm Hg, and as the mask maintains my blood oxygen at the same saturation as at sea level, then that's the partial pressure of oxygen while I'm wearing an oxygen mask. Eighty is clearly greater than forty, so even at 18,000' breathing is better than holding my breath to maximize blood oxygen during the mask swap.

So at what altitude should I hold my breath? At 32,800' the partial pressure of oxygen in the atmosphere is 25% of the sea level pressure, which is 40 mm Hg, the top of the range for lung capillary pressure. I would say, "so up to 32,000 it's better to breathe than hold one's breath when swapping oxygen sources" but above 32,000' the time of useful consciousness without oxygen is around a minute, even with no physical activity, so one shouldn't be messing around with one's oxygen source at such altitudes. But my conclusion is that above that, hold your breath for those few seconds of scrabbling before you either get your oxygen on or forget how and pass out.

I only took biology to about grade eight, so most of what I know about the human cardiovascular system comes from lifeguard class. I welcome any corrections to this analysis, even if you're stopping by years after I wrote it.

Monday, October 19, 2015


I was away working last weekend, so I wasn't really thinking of Thanksgiving as a holiday. I usually work right through October, so a proper Thanksgiving celebration only happens by chance. Sometimes a little late, like the one I had this year. But with or without the dinner, I'm still thankful for things that happened and those that didn't.

Things happen and things don't. Whether they happen or fail to because of our own skills and planning, because of stochastic processes, or because of an omnipotent being, I am grateful when the right things happen and the wrong things don't. Neither history, nor science, not even religious texts seem to indicate that gratitude or the lack thereof has great influence on what happens and what doesn't, but I still have gratitude. The engines turned when I needed them to. The electricity flowed when I depended upon its service. The ice and the air and my wings did not interact in a way that had a disastrous effect on my flight. Over the years, the malfunctions that have occurred in flight did so after sunrise, within single-engine fuel range of a usable airport, once I was clear of IMC, when I had sufficient altitude, or before I was too tired. I saw what I needed to, and am surrounded by those who look out for me. I am grateful.

Also, you will find it hard to convince me that there is a better way to eat leftover turkey than cold, with my fingers, while standing in front of an open refrigerator.

P.S. to foreigners: Thanksgiving is a post-harvest festival that Canadians celebrate on the second weekend of October. It's not a public spectacle or a commercial event (for places other than grocery stores), just something you do in your home. People with normal jobs get a day off work on the Monday, but family or groups of friends will get together on any of the weekend days for a meal, usually involving roast turkey and seasonal vegetables, especially squash. If you're crafty you can score two or even three turkey dinners over the weekend, and everyone eats turkey sandwiches, turkey soup and turkey salads for a week afterwards.