By Phillip Johnson, EAA 378381, Webmaster, Ottawa Chapter 245, Canada Council Board Member
It was January 3, 2022, the sky was clear, and the wind was scheduled to be down to a few knots and straight down the runway from the west. It seemed like the perfect winter day to go flying, albeit a little cold at ‑15°C. I checked my “AutoDens” app on my iPhone and it told me I was going to have a density altitude of -3,800 feet even with the airport elevation of 420 feet so I expected performance to be high. I had deliberately delayed the flight to the mid-afternoon as the wind was expected to be changing to the favourable “straight down the runway” condition, which it did, but I didn’t think about the bright afternoon sun being so low on the horizon. I also forgot my ball cap in favour of my toque. While the toque is warmer, the Lightspeed noise-cancelling headset does not seal well when I wear the toque, so I favour my ball cap, which is particularly important when flying with the sun low on the horizon, and I just raise the hood of my hoodie to keep my noggin warm. All of this goes to show how we forget things when we are cold. Anyway, I pushed the Cozy out of the hangar and onto the apron in front while I closed the hangar door. I climbed into the Cozy and went through all of my checks before closing the canopy. What I didn’t realise was I had deposited a tiny amount of snow on the top longeron which is the sealing surface for the forward hinging canopy of my Cozy. When it came time to close the canopy, the pilot side just didn’t want to close, but after a lot of persuasion, I did manage to pull it down and lock it. What I had not realised was the small amount of snow was causing the canopy to leave a small air gap. There is no flexible seal here — the seal comes about from a perfect fit between the canopy and the top longeron and now that had been compromised.
In the past, the coldest flight was around -10°C so I was expecting similar heating performance. I had made some modifications, when I built the Cozy, that would prevent air leakage even around the elevator torque tube penetration which is notorious for bleeding cold air. I had also made some exit vents under the nose and at one of the cockpit’s most forward points so that warm engine air would be pulled through the cockpit and past my feet thereby keeping my feet warm. These mods had worked perfectly in the past and I was expecting similar performance for this flight. Unfortunately, this was not to be the case, and my feet froze after an hour in the air, and my gloved hands were not much better. I could hear a slight whistling sound even through my Lightspeed noise-cancelling headset and no matter how I searched I could not find the cause. The poor seal around the canopy, resulting from the innocuous snow on the top longeron, caused the heating system to fail, and it wasn’t until I exited the Cozy to push it back into the hangar, did I see a small amount of snow/ice which accounted for the poor seal and why I had had so much difficulty getting the canopy closed.
So here is the takeaway: when you want to go flying and its cold outside, be meticulous about everything. When I realised I did not have my ball cap, I should have shut down and gone back into the hangar to find one, as it is important when flying with the sun low on the horizon. When the canopy did not want to close, I should have looked into the reason rather than figuratively getting a bigger hammer. The flight would have been so much more fun had I just spent the extra time to do that. The sky was clear, the wind was light and steady, and I anticipated fantastic climb performance. Instead, I wanted to get inside, close the canopy, and be out of that biting cold.
On the next cold but clear day, I’m going to make a point of going up and see if I can replicate the flight conditions but wearing the correct clothing and making sure the canopy closes correctly. That way I can confirm I have an adequate heating system.