Not your typical turbulence question. I was in a cross country flight and we were at 38K feet. We were going to be flying over a storm so I expected some bumps. As were were getting bounces around pretty good the pilots descended to find clearer air. I understand air may be more turbulent at different altitudes but does it make sense we descended in that case or did we do it for another reason. Also can you have less turbulent air at lower altitudes often, or is that rare?
Lavender Room
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Re: Pilots of the LR [windywave]
[ In reply to ]
The antique 4-seat spam can I fly can't get anywhere near that high. But yes, clear air turbulence is common when you get a strong jet stream with a sharp gradient in wind speed. Basically if the wind profile looks like the figure on the left, you're gonna have a bad time if you're in those red boxes. In your case it was either impossible (ATC restrictions or the service ceiling of the aircraft) to get above it, so the next best move is to descend.
Re: Pilots of the LR [KoopaTroopa]
[ In reply to ]
Cool graph!
Although it reminded me of two things when I saw it - one being a dog's tail...
king of the road says you move too slow
KING OF THE ROAD SAYS YOU MOVE TOO SLOW
Although it reminded me of two things when I saw it - one being a dog's tail...
king of the road says you move too slow
KING OF THE ROAD SAYS YOU MOVE TOO SLOW
Re: Pilots of the LR [KoopaTroopa]
[ In reply to ]
KoopaTroopa wrote:
The antique 4-seat spam can I fly can't get anywhere near that high. But yes, clear air turbulence is common when you get a strong jet stream with a sharp gradient in wind speed. Basically if the wind profile looks like the figure on the left, you're gonna have a bad time if you're in those red boxes. In your case it was either impossible (ATC restrictions or the service ceiling of the aircraft) to get above it, so the next best move is to descend. But we descended from above a storm into the storm.
Re: Pilots of the LR [windywave]
[ In reply to ]
The commercial airlines swap information about where to get a 'smooth ride'. Many flights are travelling through the 'same air' so to speak on published airways at various altitudes. Sometimes, there are several flights from the same airline that are using the same airways and they will share turbulence reports with their company dispatcher about where they are getting a rough ride because they know there are several more of their company's aircraft scheduled behind them in the next 1-2 hours. Additionally, the FAA has an official system for Pilot Reports (called PIREPS) that are public for anyone that wants to look them up. They are filed in the air over the radio with ATC and shared with all aircraft. The most frequent uses are for icing and turbulence. Last, sometimes AIRMETS for turbulence are published by the FAA in weather briefings as a result of computer models that predict turbulence due to expected wind shear.
Clear air turbulence (CAT) can be caused by wind shear. If you have air masses moving in different directions overlapping each other, the transition area between the two air masses will have ripples or shear waves that are felt as turbulence in the aircraft. It might be beneficial to descend in that case if the lower air mass is more of a tailwind than the upper air mass or if the aircraft doesn't have the ability to climb any higher as mentioned above. In mountainous areas, mountain wave can also be a source of turbulence.
I suspect that in your case, the pilot found out he could get a smooth ride at a lower altitude either from another plane with his airline or ATC gave him a PIREP from another aircraft.
Greg
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Clear air turbulence (CAT) can be caused by wind shear. If you have air masses moving in different directions overlapping each other, the transition area between the two air masses will have ripples or shear waves that are felt as turbulence in the aircraft. It might be beneficial to descend in that case if the lower air mass is more of a tailwind than the upper air mass or if the aircraft doesn't have the ability to climb any higher as mentioned above. In mountainous areas, mountain wave can also be a source of turbulence.
I suspect that in your case, the pilot found out he could get a smooth ride at a lower altitude either from another plane with his airline or ATC gave him a PIREP from another aircraft.
Greg
If you are a Canuck that engages in gratuitous bashing of the US, you are probably on my Iggy List. So, save your self a bunch of typing a response unless you also feel the need to gratuitously bash me. If so, have fun.
"Don't underestimate Joe's ability to f___ things up" - Barack Obama, 2020
windywave wrote:
But we descended from above a storm into the storm.There are storms and there are STORMS. No pilot with a brain is going to knowingly go into an honest to goodness no shit supercell thunderstorm unless they are truly out of other options. But there's an entire continuum of conditions between clear skies/unlimited visibility and a storm that will tear the plane to pieces. Given that you were topping it at FL380 it likely wasn't that severe, and as Greg already mentioned they almost certainly had some PIREPs that it was better down there.