This past week, yours truly captained his third and fourth Hope Air missions, this time to catch then to release a fine gentleman from Chapleau in northern Ontario, who had a medical appointment in Toronto. Winter having arrived, this trip featured entirely too much ice.
When flying, ice is of concern several ways. The standard boogaboo that student pilots are scared with is the type of ice that an airplane can pick up from cold wet clouds. This type of ice builds up on the wings and on other sensitive systems, and can bring an unequipped little airplane crashing down. While we did take a little of this kind of ice, the airplane shedded it as its deice equipment worked, so it was not the problem.
No, the problem was something drivers and other ground-dwellers know too well: ice on the ground. Even at larger airports, a good snow blizzard can suspend operations for a while, as the snow is shoveled off of runways and such. But a blizzard that occurs in ambient temperatures that fluctuate above and below freezing point causes a worse situation, since the snow can melt and refreeze, producing a hard coating of ice. Repeated over a few hours, the ice can become thick, and without chemicals or extra sunshine, impossible to remove. This was the situation of our first visit to Chapleau last week. After a day of wet snowfall, and a night of cooling, both runways were covered with “70% black ice, 20% wet snow, 10% bare”.
While airplanes don’t drive their wheels for propulsion like cars do, the wheels are expected to provide some resistence to sideways movement, so that once the airplane’s aerodynamic control surfaces don’t work any more (because we’re moving too slowly), the vehicle keeps rolling straight ahead. Most landing accidents that occur tend to be because of loss of control during this very rolling phase, even when stiff crosswinds substitute for runway ice as a malevolent influence.
Hope Air flights are all supposed to be non-emergency charity trips, in that there is no risk to life if a volunteer pilot cancels the flight at the last minute. In fact, the Hope Air pilot manuals make it clear that flights are totally at the discretion of the pilots, and that the patients know that these little planes might have to cancel their flights even at the last minute. On the other hand, I’ve heard that sometimes medical appointments may take weeks or months to reschedule in case a Hope Air flight is aborted. The main reason that I joined the Hope Air organization was to be exposed to flying conditions where there is a strong incentive to complete a trip, even when conditions are adverse. It’s a great way to combine experience-building and fellow-human-helping.
With all these factors in mind, my co-pilots and I set out on the trips mindful both of the poor conditions at CYLD and of need to make it anyway. When we first arrived at Chapleau after a 2h30m flight, we found out about the black ice, negative air temperature, and the absence of chemical ice melters, plus some extra winds to make it even more uninviting. We circled around for a few minutes discussing the situation with each other and over the radio with a helpful fellow at the airport. We decided to give landing a try, ready to “go around” at the slightest problem, willing to abort the mission even after we’ve come so far. We lined up for the longest and widest runway, touched down at minimum speed, and used no brakes at all for a while. The large momentum of the airplane helped keep us centered during the rolling part of the landing, though we could feel that the wheels might have been just slipping instead of rolling. Throughout the maneuver, I used differential power (modulating left vs. right engine thrust) to help the steering, and this was just about enough to gently slow us down and keep us under control.
Only at one point during the first landing was I concerned, as I locked up the brakes during a sharp turn onto an intersecting runway. Even though we were moving at a very fat old lazy snail’s pace, the airplane still veered toward the edges, until I listened to my co-pilot, released the brakes, and with wheel rolling restored, could gently steer it back on track. Whew. After what seemed like an eternity, we shut down in front of the terminal building, I jumped off the airplane in relieved elation, and nearly slipped & fell. It would have been poetic justice to injure myself such a silly way, I suppose.
For the next hour or two, with the patient having arrived for the flight, we just stared at the apron not quite believing what we had done, worrying about how we’ll get out again. Somehow fortune was smiling in our general direction, for the local weather observation fellow noted how rapidly ground temperatures were climbing: it went from -4C to +0.2C. Eventually we decided to give it a try, now starting to see some bare wet black asphalt islands among the seas of wet ice and snow. We packed up, rolled very gently to the upwind end of a runway, turned around, and started our take-off. The first three seconds were good, but were followed by an insistent lurch off to the right. This sort of thing happens normally in the twin as the two engines spool up to full power at slightly different rates, and is easily controlled on a dry surface with nosewheel steering. However, this time we had no effective nosewheel steering, requiring aggressive differential thrust to get back onto the centre line. Over the next fifteen seconds or so, the airplane accelerated despite my continuous thrust modulation, until we could lift off and let off a little cheer. The first flight home was wonderfully uneventful.
Fast forward a few days, to return delivery day. The patient has completed his appointment, and done some extra christmas shopping to defeat (in his words) Chapleau cabin fever, and was ready to go home. Conditions at CYLD were reportedly better, in that despite snow over the intervening days, the air was very cold (-20C). Cold snow is good snow: not too slippery. After a gusty Toronto take-off, and a smooth long flight, my new co-pilot and I decided to land without much ado. Though it was much better than a few days before, we still had to play with differential power to complete the taxiing process. We dropped off our grateful patient, topped up the fuel tanks, ate some snacks, and proceeded to a thankfully uneventful takeoff and eye-candy filled return flight. Only back in the Toronto area did we encounter complications from some turbulence and light airborne ice of the bugaboo kind, but a few minutes later the Hope Air missions came to a completely successful closure. I wonder what’s next.