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-   -   Severe turbulence/mountain wave 10th March 2007 (https://www.pprune.org/tech-log/267511-severe-turbulence-mountain-wave-10th-march-2007-a.html)

BOAC 11th Mar 2007 19:13

It is PAN PAN PAN "xxx Emergency Descent". If, as we are led to believe, the Spanish and French do not understand this emergency prefix, then make it "Mayday". Turn off track (helps the descent) and down you go. ATC can sort it out. The odds are stacked in favour of not hitting anything against losing control.

Do not linger in SEVERE turbulence waiting for Pedro or Louis to respond, or you will find yourself descending anyway, but out of control.:)

Final 3 Greens 11th Mar 2007 19:52

garp

I will tell pilots to standby when needed, different pilots have different degrees of turbulence tolerance and I will certainly not loose separation because of some whimp feeling a bit uncomfortable.

Your attitude is idiotic.

Aircraft have bee destroyed by severe turbulence.

Caracas 11th Mar 2007 20:10

Well said.

Have been in severe turbulence in the Madrid area. Cabin was a mess speed all over the shop.

Not the place to linger for too long.

Desk Bound 11th Mar 2007 20:26

An interesting debate. Severe turbulence is never pleasant. A few years ago I was flying south west from Dakar at night and entered severe turbulence that induced a 3000'/min ROD in a 4-engine heavy with max thrust applied. I would have dearly liked to have had an air traffic controller respond to my RT as they will in Europe - even if it is 'Standby'!

That said, I also had severe turbulence (mountain waves) east of the Rockies where the Mach went from 0.86 to 1.1 and down to 0.5 quicker than I can type it and all we could do was to hang on and attempt to fly attitude. Sadly, the US controller seemed less than interested - but fortunately we came out the other side fairly quickly.

In both cases, it is something I would prefer not to experience again - and night always makes it worse. However, whenever I find myself in an emergency or urgency situation I welcome the crisp and professional response of the UK controllers - in my experience they are generally superb.:ok:

garp 11th Mar 2007 20:35

F3G, it seems you haven't read my complete post which continues as follows
"Whenever possible he will get descend, if he has to wait and cannot he should declare that he's unable to maintain level and emergency separation can be applied."
From your comment I understand that every a/c reporting turbulence has to be descended/climbed regardless of traffic or degree of turbulence. Good going. Again, just for the sake of clarity, when you declare that you are unable to maintain level you will be descended/climbed and emergency separation can be applied. Rest assured that any pilot asking for a level change due turbulence will get it but not at any price. As a final note you can also rest assured that we will try our very best to warn you about turbulence and try to plan you at different levels.

woodpecker 11th Mar 2007 20:57

Garp...

Perhaps your "some whimp..." understandably upset a few.

Having used Pan Pan at 6000 in the LHR TMA in a 767 and ended up in Stansted with an AOG a/c (following the QAR "G" record) I would have objected to being called a whimp.

Wannabe1974 11th Mar 2007 20:58

Would severe turbulence justify a mayday? Before anyone starts, I am not getting at the guy who posted that! Just wondering...
I would have thought a Pan would be more appropriate until actual bits of aeroplane start worrying the Pyrennean goats...
Am I talking rubbish?

BOAC 11th Mar 2007 21:22


Am I talking rubbish
- possibly. Please re-read post #22

tbaylx 11th Mar 2007 21:29

I think it's the wimp comment that riled a few guys. ATC isn't going to clear you to a lower level without making sure you have seperation. We ask for lower or higher all the time due turbulence, most of the time we can wait for them to check with another sector for conflicting traffic. The guys on the ground don't know how bad it is, or that you need immediate descent. If its bad enough that you're about to run the airspeed indicator out the bottom and plummet from the sky declare the pan, or mayday..turn offtrack and down you go.

You can sort the rest out later and keep an eye on TCAS in the meantime. ATC won't give you a clearance, nor should they unless its safe and legal for them to do so. If you want down before that, do what we'd do in any other situation that warrants it, declare an emergency, take your own seperation into account and descend.

Bandit650 11th Mar 2007 21:52

Just out of interest ... could someone outline what this severity of turbulence actually feels like? I'm imagining a scene where instruments can hardly be read, you'd immediately and violently depart your seat if not stapped in, wings flexing all over the place, or in other words like being violently shaken as if in a cocktail shaker...would appreciate an insight for future reference. Thanks.

TotalBeginner 11th Mar 2007 21:54

Interesting thread!

Is the turbulence that you talk about in this region a seasonal thing?

RV1 11th Mar 2007 21:58

Controllers will always try to give you descent due to turbulence if you request it but there are a number of reasons why you may be told to standby, such as...
1. You're still in another sectors airspace (especially if you've just been transferred) and we need to co-ordinate descent with the previous sector before we can descend you.
2. There's other conflicting traffic which we need to get out of the way first.
3. We're busy trying to give descents to the other a/c experiencing the same turbulence. Weather and turbulence can really increase our workload. We will try to give you what you want as soon as we can as we all know what it's like to be in the back of a plane in turbulence but bear with us!

BOAC 11th Mar 2007 22:02

Bandit - not necessarily - it could be severe mountain wave where the speed goes from stall warning with full power to limit speed with throttles closed. Descent is the only option. Luckily only seen that once. Also came close in a twin piston over the Scottish Highlands.

Not always a 'shaking'. :)

Bandit650 11th Mar 2007 22:23


Originally Posted by BOAC (Post 3172794)
Bandit - not necessarily - it could be severe mountain wave where the speed goes from stall warning with full power to limit speed with throttles closed. Descent is the only option. Luckily only seen that once. Also came close in a twin piston over the Scottish Highlands.

Not always a 'shaking'. :)

Thank-you. I didn't know that. Got me curious now..will have to go and read all about it!:ok:

Shoo shoo 11th Mar 2007 22:38

Forecast
 
On the last page WWW said it was not forecast. I understand that the Tramontana was forecast on local radio & TV for Catalunya, with windspeeds "Up to 140kph"

Maybe not joined up met reporting?

Caracas 11th Mar 2007 22:51

There was nothing on the significant weather charts or any SIGMETS.

The only SIGMET was for the Barcelona FIR expiring around 1500Z.

tired 11th Mar 2007 23:04

Many thanks to the southbound Speedbird who warned us about this whilst we were still in Algerian airspace (heading northbound). They went through the area at F310 and apparently had a very rough time. When we got there we were at F400 and it wasn't bad at all - a couple of minutes of "moderate", with speed excursions of +/- 10 knots - no sweat. Sometimes it pays to go high!! :)

J430 12th Mar 2007 00:24

I know this might be a "how long is a piece of string" question, but i see most folk are wanting a decent. I only fly bugsmasher altitudes and getting away from mountain induced turbulence is usually by flying as high as you can. Obviously with very high terrain its different and maybe you are flying below the waves, is that what you are trying to achieve? how do you determine which is better climb or decend?

J:ok:

Wee Weasley Welshman 12th Mar 2007 00:42

The lower you go the thicker the air the more scope your wing has to avoid a stall or overspeed. To put it in stupidly simple terms.

I don't know of many that would prefer to climb closer to coffin corner to avoid turbulence...

Cheers

WWW

411A 12th Mar 2007 02:44

Severe turbulence is easily handled....let the co-pilot fly the aeroplane.
No one is the wiser...:}


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