It was too cold or perhaps too windy last night for overnight frost, so we get away without having to clean the airplane. We just need to wait for a layer of cloud at the airport to lift or scatter out. While we are waiting we chat about the forecast to the CARS guy on duty. The TAF is calling for 4000' broken, but the last three METARs have had a ceiling of 2500'. We ask him if the 2500' is still his best guess. He points out the heights of some of the nearby hills that he is using to gauge his observations, and explains that it's common for the TAF to remain at odds with the forecast for hours. (Usually a forecast shown by reality to be incorrect is updated, cleverly 'predicting' that the weather will continue to be what it is. It's not just making the forecasters look better: it's safety). But our CARS guy says that the TAF here is rarely changed to reflect reality. He has had the Edmonton Environment Canada forecasters telephone him to say that it can't be snowing, when his submitted observation contains snow. I really think that a guy who lives in the Yukon Territory should be trusted to identify snow when he sees it.
I suspect there may be some sort of political issue at work where the Environment Canada forecasters grudgingly acknowledge the Nav Canada folks who are their eyes and ears at all the reporting aerodromes, but deny the existence of CARS personnel. It's true that CARS workers don't have the same training as flight service specialists (and they aren't in the union), but they provide a valuable service at airports that would otherwise be unstaffed, and they can usually be trusted to look out the window. There's even talk of leaving CARS observations off the Nav Canada website that distributes Environment Canada forecasts. That's not right. Pilots should have access to all available information, be it autostation, FSS, CARS or the copilot's grandmother looking out her window. We know from experience the relative reliability of the different observers and would rather make up our own minds about what to believe.
At the next observation he calls it 3000', and says it might be a little more, he's being conservative. We needed to get to a thousand metres over the airport to do our job, and that's a little more than 3000', so we decided to give it a try. The time-building pilot graciously offered the left seat and controls to me--apparently our insurance company doesn't care if the time he builds is dual or PIC--and I accepted.
I take off and fly north of the airport. At 5700' on my altimeter, we are 1000 metres above the ground, and just below the cloud bases. I turn and fly over top of the airport. By the time I am south of the lake, the other side of the runway, there are tendrils of cloud reaching for the airplane and I descend. I call back with a PIREP. "Cloud bases over the airport are five thousand seven hundred indicated."
He asks, "Is that ASL?"
I say yes, even though that's not quite true. Someone with FSS training would know that the indicated altitude is similar to the altitude above mean sea level, but is not corrected for temperature. And as I write this I realize that seeing as I know I was 1000 true metres above the ground, and that the airport elevation was 2255' asl, we can work out exactly how much that temperature correction needed to be.
One thousand metres (thanks Google) is 3281'. Add the height above the runway to the runway elevation and I was 3281 + 2255 = 5536' asl while indicating 5700'. That's because the air below me was colder and thus denser than standard and thus the pressure drop in my climb through 3281' was equivalent to the pressure drop after climbing 164' more in standard temperature air.
Pilots will be able to use the above information to calculate the temperature at the aerodrome. I'll write more about cold temperature corrections later.
The area of cloud ended about ten miles north of the airport and I climbed up over the mountains with blue sky above. Even though there was a fair amount of wind we had almost no turbulence. We were all giddy with the beauty of the scenery, and our proximity to the spectacular peaks. "Oh, traffic," pointed out my co-worker and I looked, startled, not having heard a word on 126.7 or 123.2. We saw a small single leave the crooked runway hours ago, but he didn't climb much so we probably just going to a nearby camp. I swivel my head looking until I laugh to see that he is teasing me, pointing out contrails in the sky, far overhead.
"Are we still working?" asked the mission specialist, and we were. What a job. It was a bit of a disappointment to have to dip back under the clouds to still-overcast Watson Lake at the end of the day.
I know I already typed part of this, but I can't find it. I think I must have opened the same blog entry twice in two different windows and saved the wrong one, overwriting changes. Or you'll get to read part of the adventure twice.
"You engaged in conduct that put your passengers and your crew in serious jeopardy ... while you were on a frolic of your own."
As mentioned in comments a couple days ago, the pilots of the errant flight NW188 had their licences revoked by the FAA. Here's an image of the letter the captain received. They sent each pilot three copies: regular mail, FedEx and certified mail. Ouch. I feel really badly for those guys. I'd definitely be good for a few beers for them to cry into.
Update at 0208Z: I edited the post to remove the implication that Nav Canada produced the faulty forecast. As a Nav Canada reader pointed out, they just publish the stuff, and also suffer when the forecast is way off.