Friday, February 09, 2007

It was the middle of January '99 and I was in Goderich, flying a B-58 Baron for Western Air Services. Western Air was owned by a parent company, involved in grain handling, and we had to take the president to Toronto for a meeting. That task fell to myself and Scurvydog, a pilot/friend who I worked with at Western Air for a few years.

Now in the background was the "Storm of the Century". From January 2nd to January 15th, a series of snowstorms stalked the city, dumping nearly a year's amount of snow in less than two weeks. In all, the city recorded the greatest January snowfall total ever with 118.4 cm and the greatest snow on the ground at any one time with 65 cm. The mayor of Toronto even called in the Canadian Forces for emergency help, asking them to rescue stranded motorists and people immobilized by the huge snowfall.

But before the snow could be removed from the ground, it had to fall through the air.

Anyway, we planned to fly from Goderich to Toronto Buttonville, which is a general aviation airport about 15 miles away from Pearson. We'd hang out there for a few hours while the boss attended his meeting, then we'd come back to Goderich.

A few words about the Beech Baron...The B-58 is unpressurized and has no turbochargers, so the most efficient cruise altitude is fairly low, around 5,000 - 8,000 feet above sea level. Any higher than that and the engines really started to run out of jam due to the thinner air, but with no reduction in fuel consumption, so we generally flew the airplane fairly low.

The flight to Buttonville was unremarkable, with one exception: I thought it was interesting that the temperature at 7,000 feet was higher than the temperature on the ground, and that was caused by an inversion due to whatever storm system we were flying through. On the ground it was like -8c, but at 7,000 feet, the temperature was +1c. We had encountered moderate mixed icing on the way to Buttonville, but the de-ice boots had removed it efficiently and it hadn't really been a consideration. When we landed, Scurvydog and myself had chipped all the residual ice off the wings and tail, and the plane was entirely uncontaminated.

Once the plane was cleaned, we hung out at the airport restaurant, had a nap, and voila, it was time to go home. Our boss showed up around 3pm, and we departed Buttonville back for Goderich. We were in solid cloud from the time we lifted off, which is not unusual for winter around the Great Lakes region.

We planned for a cruising altitude of 4,000 feet for the return leg, and that's what we climbed to. We cruised for about twenty minutes in solid cloud but smooth air, occupying ourselves with talk of the beers we would drink at the local pub once we were done our mission.

And then the most remarkable thing happened.

Ice began to form on the wings and on the windshield. But it wasn't rime ice, with large milky frozen drops, nor was it clear ice, with smaller, clear drops. It was more like soft sculpture all along the entire surface of the wings, not just the front couple of feet. After a very few seconds of this, the ice on our wings looked like frozen waves crashing on a shoreline. The ice was a few inches thick in no time at all. I could tell this by looking out our side windows - our windshield had been completely coated in ice within a few moments.

We cycled the de-ice boots, but they only removed a small amount of ice on the front of the wings and did nothing about the 5 feet of ice forming aft of the boots.

For those of you who aren't familiar, if ice forms on an airplane wing (or tail), it seriously screws up the airflow over the wing, reducing lift and increasing drag. In Canada it's illegal to take off in a plane that has *any* ice on any lifting surface of the plane. It only takes a bit of ice to affect performance in a big way, so having 3 - 4 inches of it hanging off our airplane meant we weren't in a good situation.

Our airspeed decreased by 30 knots nearly instantly, and putting the engines to full power didn't improve the performance at all. The plane was loading up and getting ready to descend whether or not we were at an airport.

I knew there weren't any airports near our position, and all the local airports had the same problem anyway - at small airports like the Goderich airport, you have to visually align yourself with the runways for landing, and as I couldn't see out the windshield at all, this would be a tough task.

The speed kept decreasing, the ice sculpture on our wings thickened, and I was starting to seriously think about an off-airport landing, maybe yawing the airplane and looking out one of the side windows so try to dodge power lines or trees or whatever.

Then I had one of the few brainwaves I have been lucky enough to be struck by. At 4,000', it was -3, which is an idea temperature for the formation of ice. But I remembered that at 7,000' the temperature had been above zero.

Our airspeed was back to around 130 knots and in ice the Baron stalls at 100 knots or more, so we didn't have a lot of extra performance play with. I wasn't sure if the plane would climb any more but we really didn't have any other options so I got Scurvydog to call ATC and ask for higher. The engines were already at full power, so I just pulled the nose of the airplane up and waited to see what would happen.

We started to climb, thank Jebus.

It took a few minutes to reach 5,000' with the ice accumulating and our airspeed dropping all the while. At the lowest, I seem to remember us indicating 120 knots, which is 60 knots slower than normal, and probably fairly close to the stall speed on an iced-up Baron. At 5,000' we were getting maybe 200 feet per minute in the climb, which is pretty damn low for a twin-engine plane with both engines running. But the temperature was slowly rising, and at 5,000' it went to 0c. As we slowly headed back up to 6,000', the sculpture started to melt and fall off the wings. Our airspeed started to increase, and I was eventually able to reduce the power on the engines, saving a little wear and tear on them, and decreasing our cabin noise level by at least half - the Baron is a loud little beast when the engines are running at full gallop.

At 6,000', we were climbing at 600 feet per minute and the temperature was at +3c, so life was getting a little easier on us. We still couldn't see out the windshield, but we'd poke that cat when we got to it. We had a plan now, and Scurvydog and myself were both a lot happier. Our boss in the back remained oblivious to the whole thing; he read his magazine and napped.

We arrived over Goderich airport at 6,000' with almost no ice left on the wings and a nice big open patch on the windshield that I could see out of. We extended our flaps and our landing gear, then cut the power and dropped like a stone toward the runway, descending through the 'bad' air as fast as we possibly could.

In a small twin-engined piston airplane it's normal procedure to 'baby' the engines, and to reduce power slowly when coming in to land so the engines don't cool too fast and possibly crack cylinders. I didn't care about that at all, I just wanted us to get on the ground - a mechanic could replace the cylinders easily, and I wasn't about to spend 10 minutes slowly descending through the ice clouds and arriving back in the same situation I started out in.

The landing was uneventful also, but it was kinda funny when we touched down - Scurvydog and myself both audibly sighed with relief, which prompted our boss to make his only comment during the flight

"Wow, I didn't think you guys would be so happy to get back to Goderich. Is there a big party going on tonight?"
"Yes sir, it's a celebration. We've been planning it for some time now"
"How long?"
"For about half an hour"

He looked puzzled, then opened the door to the Baron and left us to sit, shaky and giggly, and really, really glad to be on the ground, safe and sound.

What our mechanic said to me the next day after he inspected the engines is another story entirely, one for another day.


Blake said...

Gotta love those winter storm systems..

A good example of when lower doesn't necessarily mean better when it comes to icing and temperatures.

Can't wait to hear what the mechanic had to say ;)

Linn/Swedish Aviatrix said...

Oh, how I do love flying turbine engines (B300/350) and being able to fly comfortably at 30,000' where the big bad ice can't get to you. Climbing and descending is another matter, of course... But still. The thought of winter weather in Sweden (think Canada) and cruising IMC att 4,000 feet makes my toes curl...

Cameron Allison said...

Did you ever tell the story of what the mechanic said to you the next day?