Wednesday, January 24, 2007

Last night I ate some new food. I'm fearless when it comes to new grub, but this was particularly difficult. They called them rocky mountain oysters but they ain't seafood. They were actually pretty tasty, but I worry about the karma associated with my actions, especially if the bulls come looking for what was missing.


The landscape we flew over today is like the surface of the moon. Beautiful, but stark.

Did 6 hours of flying today, a couple of which were sneaking through some really rough air. The sky was clear but the jetstream was being ornery, twisting this way and that through the flight levels. People ahead of us were complaining bitterly about the ride, and we started to get constant moderate chop. Moderate turbulence is when we can still control the airplane just fine, but we are pressed against our seatbelts firmly due to the bumps. Then an MD-82 just ahead of us reported severe turbulence just under us, so that got our attention pretty fast.

I wonder what severe turbulence in an airline jet looks like? I'm guessing lots of screaming and bags falling out of the overhead bins, which would be my primary worry if I was a passenger - did the guy sitting in the seat just ahead of me store his lawndart collection right above my head, and did he really make sure the latch was closed?

By definition severe turbulence is when the airplane is momentarily out of control and is subject to violent changes in pitch, roll or yaw, along with altitude deviations. When the air is rough we slow down to manoeuvering speed. What's that? It's a speed below which a big gust of wind will cause the wing to stall. In this case, stalling the wing can be a good thing because a stalled wing isn't producing lift and that means it's not creating a load on the airframe. To be technical, it's not so much the speed that's important, it's the angle of attack of the wing through the air, but I can't be bothered to teach a physics course right now so we'll just go with the simple explanation: A relatively low speed is good for penetrating really rough air. If we are going really fast and we get a huge gust of wind, the forces on the wing might actually damage it, and in a worst-case scenario, it can cause the wing to depart the airplane which is a profoundly career-limiting move.

Anyway, today we had to descend through some areas where multiple aircraft had reporting really uncomfortable air. We stayed up high until the last minute, then popped the speed brakes, pulled the throttles back to flight idle, and dropped like a stone to our destination airport, our theory being that the less time we spent in the rough air, the better. It worked fine, and we only had a few good jolts.

Unfortunately once we got gas at our destination, we had to take off and climb back up into the rough air. It wasn't much fun for my pax, but we managed to get back up to 37,000' with relatively little discomfort. The hard part was having to listen to several other aircraft whose pilots were clearly in distress - we could hear their voices wobbling as their aircraft were tossed about, and we could hear the stress in their voices. There but for the grace of...

On the upside, once we got into the jetstream we had a nice speedboost as it was going our way.

90 knots on the tail gives us a decent groundspeed for a 550 :)

After 600 miles of rough air, we finally made it into a more smooth area and things settled down. We were able to loosen our seatbelts a little and the pax were even able to eat their catered lunches.

When I got home, I found this in my living room:

I have one too, but it's in need of some TLC since my last few flights / crashes.

I have an early morning flight headed east tomorrow, so I'm off to bed.

1 comment:

Anonymous said...

Cool! You flew over my house. :) I live about 5 miles from the JOT Vortac. Probably only interesting to me but since I read this blog every day I thought it was neat anyway. :)