Severe Turbulence
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Severe Turbulence
One of the questions that I ask of my colleagues on almost every flight is if they have ever encountered severe turbulence. It is always interesting to hear of the responses. Often most everyone says that they have at least one or two experiences with it.
Airline operation manuals describe severe turbulence differently I have discovered (mine has general criteria up to extreme) and this often causes some rather odd comments--particulary over the North Atlantic. It seems that some aviatiors spend ever moment of their crossing with the fleshy part of their finger pressed against the transmit switch to question anyone who has made a severe call--something that I find a bit presumptious that another aircraft can determine what conditions a flight is encountering miles away...
I can remember a couple of years ago hearing a severe call from a Lufthansa flight as he was being passed over from Moncton Center to Gander. Immediately another flight was asking Moncton where the position of the Lufthansa flight was that "had lost control." Well, you can imagine that the controller was in disbelief as well as everyone else in the air who thought this guy was not someone you would like to fly with.
An equal calibre person-to-avoid was one I heard a few years past grilling a biz jet over 30 West over his call. Not asking exact position of flight level, this guy was sharply demanding "how badly his aircraft had been damaged?" When the Biz pilot repsonded that he was not aware on any external damage he took a tongue lashing about knowing the "definition" of severe. It was only after the hapless pilot described flying an aircraft with a known high wing loading and deep excursions into both the high and low speed buffet and inability at times to read ANY of the instruments that our resident atmospheric expert piped down.
Question 1: Why are some pilots so disbelieving in the idea of severe turbulence? It does NOT mean that the aircraft is totally out of control. I have always thought it is was simply "that was something I never want to have to fly through again and that you would not want others follow you into." I have had carts knocked over in the aft galley and have heard those reports through the years of broken bones etc. Is that something one would wish others to fly through by simply calling it "moderate?"
Question 2: What have been some of the PPruner's experience with severe? There must be some pretty eye-opening stories out there.
Airline operation manuals describe severe turbulence differently I have discovered (mine has general criteria up to extreme) and this often causes some rather odd comments--particulary over the North Atlantic. It seems that some aviatiors spend ever moment of their crossing with the fleshy part of their finger pressed against the transmit switch to question anyone who has made a severe call--something that I find a bit presumptious that another aircraft can determine what conditions a flight is encountering miles away...
I can remember a couple of years ago hearing a severe call from a Lufthansa flight as he was being passed over from Moncton Center to Gander. Immediately another flight was asking Moncton where the position of the Lufthansa flight was that "had lost control." Well, you can imagine that the controller was in disbelief as well as everyone else in the air who thought this guy was not someone you would like to fly with.
An equal calibre person-to-avoid was one I heard a few years past grilling a biz jet over 30 West over his call. Not asking exact position of flight level, this guy was sharply demanding "how badly his aircraft had been damaged?" When the Biz pilot repsonded that he was not aware on any external damage he took a tongue lashing about knowing the "definition" of severe. It was only after the hapless pilot described flying an aircraft with a known high wing loading and deep excursions into both the high and low speed buffet and inability at times to read ANY of the instruments that our resident atmospheric expert piped down.
Question 1: Why are some pilots so disbelieving in the idea of severe turbulence? It does NOT mean that the aircraft is totally out of control. I have always thought it is was simply "that was something I never want to have to fly through again and that you would not want others follow you into." I have had carts knocked over in the aft galley and have heard those reports through the years of broken bones etc. Is that something one would wish others to fly through by simply calling it "moderate?"
Question 2: What have been some of the PPruner's experience with severe? There must be some pretty eye-opening stories out there.
Last edited by Uncle Fred; 24th Sep 2009 at 19:08.
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Thought this might be a good place to start, my first post on PPRuNE, from a young and unemployed pilot 
1. Well, I suppose since the most widely accepted definition of severe turbulence includes "momentary loss of control" people might not want to admit that they weren't entirely in control of their aircraft in that situation? I feel that unfortunately the pilot universe is still macho dominated enough to call the one that reports 'severe turb' a wimp - no matter what the weather really might be like.
2. Hmm, nothing really on big birds, but I can remember a training flight on a DA40 where mountain waves created a large zone of moderate to severe turbulence - caused our plane to bank 80° and pitch up 40° within the blink of an eye, that was the final indication that its time to turn back...
But then again, I'm still relatively new to the business - looking foreward to other opinions!
1. Well, I suppose since the most widely accepted definition of severe turbulence includes "momentary loss of control" people might not want to admit that they weren't entirely in control of their aircraft in that situation? I feel that unfortunately the pilot universe is still macho dominated enough to call the one that reports 'severe turb' a wimp - no matter what the weather really might be like.
2. Hmm, nothing really on big birds, but I can remember a training flight on a DA40 where mountain waves created a large zone of moderate to severe turbulence - caused our plane to bank 80° and pitch up 40° within the blink of an eye, that was the final indication that its time to turn back...
But then again, I'm still relatively new to the business - looking foreward to other opinions!
Its all very subjective. One persons calling of light/moderate/sever may be significantly different to anothers.
I have only had sever once. South of the Alps at 38K and it was like running into a brick wall that suddenly fell apart and started bashing the aircraft, it was noisy, the vibration frightening and i couldn't read any instruments or grab any of the AP controls on the FCU. We descended to 21K to get out of it but then with the Alps looming, we had to climb back into it! Fortunately it had died down.
Not a nice experience!
I have only had sever once. South of the Alps at 38K and it was like running into a brick wall that suddenly fell apart and started bashing the aircraft, it was noisy, the vibration frightening and i couldn't read any instruments or grab any of the AP controls on the FCU. We descended to 21K to get out of it but then with the Alps looming, we had to climb back into it! Fortunately it had died down.
Not a nice experience!
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Question 1: Why are some pilots so disbelieving in the idea of severe turbulence? It does NOT mean that the aircraft is totally out of control.
Severe turbulence is defined as "turbulence that causes large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control.". What's not to believe in?
Question 2: What have been some of the PPruner's experience with severe?
Thread Starter
What do you mean "disbelieving?" Not believing, as in pilots don't believe severe turbulence exists, or simply not believing in reporting it as severe?
S-Guppy
More of the later as I have, on a number of rare occasions over the water, heard doubt raised as to the accuracy of a severe pirep. I am aware of the textbook definition of it but was rather surpised when someone called it that there seemed to have been so much doubt--particulary in the example of the LH flight calling severe whose pilots would certainly not be ones to blightly throw out the word.
As you stated, the aircraft may be momentarily out of control. This however, does not mean that it is and therefore my wonderment why there would be radio calls seemingly doubting someone elses call.
Does this happen often? Indeed not, but I have heard it enough in 22 years to make me think about it.
The real point of my original post however, was just to find out what experience with this there has been--whether it be lee winds or horizontal vortex tubes spawned from the jet stream. I would think that your story of the f/e hitting the ceiling would qualify as one of those severe encounters.
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Severe and extreme turbulence does exist, have no doubt. Been there, done it, didn't enjoy the roller coaster ride one bit, but never doubted for a moment that we would not survive this. (To put it into perspective, some poor souls have not survived the experience).
I've enjoyed the atmospheric 'super' roller coaster 3 times in 28,000 hours of flying, about once every 10,000 hours, probably par for the course.
I've survived numerous other "very rough rides", but I would not call any of them severe or extreme, just unpleasant. Several times I've heard reports of SEVERE turbulence ahead of us from other aircraft on the same track, battened down the hatches in advance, and wondered afterwards if we'd been sharing the same sky as the other aircraft.
It is my personal opinion that most pilots over-state turbulent conditions, but then again, that's just my opinion.
Regards,
Old Smokey
I've enjoyed the atmospheric 'super' roller coaster 3 times in 28,000 hours of flying, about once every 10,000 hours, probably par for the course.
I've survived numerous other "very rough rides", but I would not call any of them severe or extreme, just unpleasant. Several times I've heard reports of SEVERE turbulence ahead of us from other aircraft on the same track, battened down the hatches in advance, and wondered afterwards if we'd been sharing the same sky as the other aircraft.
It is my personal opinion that most pilots over-state turbulent conditions, but then again, that's just my opinion.
Regards,
Old Smokey
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I can only remember one flight with heavy and prolonged turbulence, it was a FRA-MIL on LH, on a 319. I didn't think it was particularly worrying but people were screaming and shouting for 'help'.
The captain made an announcement that we would soon be out of it, and asked those who were able to see the wings to look out. He then explained that wit the turbulence they were flexing approximately 3 metres upwards and 1 metre downwards, and that in very severe turbulence they could flex up to 10 upwards and 15 downwards, so that what we were in was relatively light and well within the tested stress limits of the aircraft.
I'm not sure if my memory is correct on those figures, someone on here will know, but even the panic stricken lady next to me found the announcement reassuring.
My biggest fright with turbulence was somewhere over Central Africa being awaken from my sleep by what seemed a massive bang, to find that we'd hit a patch of CAT and dropped a few hundred feet. That was scary, but over very quickly.
The captain made an announcement that we would soon be out of it, and asked those who were able to see the wings to look out. He then explained that wit the turbulence they were flexing approximately 3 metres upwards and 1 metre downwards, and that in very severe turbulence they could flex up to 10 upwards and 15 downwards, so that what we were in was relatively light and well within the tested stress limits of the aircraft.
I'm not sure if my memory is correct on those figures, someone on here will know, but even the panic stricken lady next to me found the announcement reassuring.
My biggest fright with turbulence was somewhere over Central Africa being awaken from my sleep by what seemed a massive bang, to find that we'd hit a patch of CAT and dropped a few hundred feet. That was scary, but over very quickly.
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First off when I hear a report of severe or extreme turbulence along my route of flight I will do everything possible from flying through that area. I see no need to question the report. I realize that nearly all pilots have a huge ego and to be honest I'm no exception, it comes with the territory. However, when a pilot chooses to ignore or disbelieve a report of severe turbulence because of the type of aircraft or type of operation the reporting source is to me the height of 'Big Aircraft' arrogance.
"Oh that was just a biz-jet, with a couple of inexperienced pilots, they wouldn't know severe turbulence if it hit them in the face." Chuckle, chuckle, nudge, nudge, wink, wink.
I have encountered severe turbulence, or extreme turbulence three times in my 40 years and 21,000 hours of flying. In all three encounters it was CAT, twice I was flying a 727 and the other occasion a Sabre 65. In all three cases the autopilot kicked off, the instruments were for all practical purposes unreadable and the aircraft was nearly completely out of control. On the two cases in the 727 we did have members of the cabin crew injured, one was hurt when the life raft stored in the overhead fell out and broke the collar bone of one person and on the other occasion a person broke his ankle when he was thrown up against the overhead and landed on his foot the wrong way.
By the way, on all three encounters there was no reports of turbulence other than occasional light to mild.
Severe turbulence is out there and ignore the reports at your own peril.
"Oh that was just a biz-jet, with a couple of inexperienced pilots, they wouldn't know severe turbulence if it hit them in the face." Chuckle, chuckle, nudge, nudge, wink, wink.
I have encountered severe turbulence, or extreme turbulence three times in my 40 years and 21,000 hours of flying. In all three encounters it was CAT, twice I was flying a 727 and the other occasion a Sabre 65. In all three cases the autopilot kicked off, the instruments were for all practical purposes unreadable and the aircraft was nearly completely out of control. On the two cases in the 727 we did have members of the cabin crew injured, one was hurt when the life raft stored in the overhead fell out and broke the collar bone of one person and on the other occasion a person broke his ankle when he was thrown up against the overhead and landed on his foot the wrong way.
By the way, on all three encounters there was no reports of turbulence other than occasional light to mild.
Severe turbulence is out there and ignore the reports at your own peril.
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I would think that your story of the f/e hitting the ceiling would qualify as one of those severe encounters.
I don't have a specific number, but would estimate several hundred severe turbulence encounters over the years (nearly all at low level in strong winds in mountainous terrain), with several dozen others in the extreme catagory.
As you stated, the aircraft may be momentarily out of control. This however, does not mean that it is and therefore my wonderment why there would be radio calls seemingly doubting someone elses call.
That said, I think it would be a grave error (or certainly could be) to presuppose what another crew might be thinking. An airplane on a given track may experience significant turbulent action, yet the preceding and following aircraft experience nothing. It happens. Wave, wake, orographic, jet-stream induced CAT, etc...not everybody finds the same bumps in the road for a multitude of reasons. To discount what the other crew has reported would be a mistake.
On a leg last year between Honolulu and Los Angeles, we experienced what I'd classify as "ugly moderate" to severe. If it wasn't severe, it was close. It didn't last long, but while we did report it, aircraft ahead of us and behind didn't report it, and aircraft on parallel tracks didn't experience it, either. I believe we reported it as moderate to severe. I think the report was accurate enough to convey what we experienced.
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but would estimate several hundred severe turbulence encounters over the years
.. the more of your posts I read, the more respect I have for your (obviously) very catholic flying background .. I can only presume that you would be a most entertaining and eye-opening after dinner speaker at an aviation event ...
.. the more of your posts I read, the more respect I have for your (obviously) very catholic flying background .. I can only presume that you would be a most entertaining and eye-opening after dinner speaker at an aviation event ...
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Definitely not Catholic, John, but much of my family is.
I've never liked turbulence (or heights, for that matter, though that's a discussion for another time). The problem is that typically a fire is wind driven, and one seldom gets launched on a fire until the wind is driving it, and by then the turbulence becomes significant in many cases. Add the heat of the day and mountains, and voila! Instant turbulence.
The best speaker I ever heard on low level turbulence and mountainous terrain was Sparky Imeson, who recently passed away (ironically, in an aircraft, in the mountains). The man was a natural teacher, and could probably have made a lecture on how to thread a needle into an interesting dinner event.
An interesting thing about turbulence, aside from it's general subjectivity, is how it's experienced in different aircraft. Wing loading makes a tremendous difference in how a given airplane will behave in turbulence, and subsequently how the pilot will perceive and report the conditions. Mass makes a big difference. The experience of the crew does too, and I suspect the nature of the operation, as well. The pilot of a passenger aircraft may be more sensetive to how his passengers may perceive the turbulence, than the cargo pilot who has no passengers (and no one therefore "looking over his shoulder").
I flew a Piaggio Avanti for a while. I'd notice that when other aircraft in the area were reporting moderate, we'd feel light chop. I don't doubt they were feeling moderate, but the airplane rode through the turbulence of chop differently, and it felt much more subdued.
I've never liked turbulence (or heights, for that matter, though that's a discussion for another time). The problem is that typically a fire is wind driven, and one seldom gets launched on a fire until the wind is driving it, and by then the turbulence becomes significant in many cases. Add the heat of the day and mountains, and voila! Instant turbulence.
The best speaker I ever heard on low level turbulence and mountainous terrain was Sparky Imeson, who recently passed away (ironically, in an aircraft, in the mountains). The man was a natural teacher, and could probably have made a lecture on how to thread a needle into an interesting dinner event.
An interesting thing about turbulence, aside from it's general subjectivity, is how it's experienced in different aircraft. Wing loading makes a tremendous difference in how a given airplane will behave in turbulence, and subsequently how the pilot will perceive and report the conditions. Mass makes a big difference. The experience of the crew does too, and I suspect the nature of the operation, as well. The pilot of a passenger aircraft may be more sensetive to how his passengers may perceive the turbulence, than the cargo pilot who has no passengers (and no one therefore "looking over his shoulder").
I flew a Piaggio Avanti for a while. I'd notice that when other aircraft in the area were reporting moderate, we'd feel light chop. I don't doubt they were feeling moderate, but the airplane rode through the turbulence of chop differently, and it felt much more subdued.
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Definitely not Catholic, John, but much of my family is.
I have no doubt that Guppy knew exactly what I meant and his response was a tad tongue in cheek .. however, for those who are not native English speakers and might be confused by the archaic reference I made (for which I apologise) -
catholic – adjective
1. broad or wide-ranging in tastes, interests, or the like; having sympathies with all; broad-minded; liberal.
2. universal in extent; involving all; of interest to all.
as opposed to the more specific meaning of
3. pertaining to the whole Christian body or church
Likewise, the couple of significant turbulence exposures I've had were enough to give me a healthy interest in avoiding the next opportunity to sample Mother Nature's talents ..
I have no doubt that Guppy knew exactly what I meant and his response was a tad tongue in cheek .. however, for those who are not native English speakers and might be confused by the archaic reference I made (for which I apologise) -
catholic – adjective
1. broad or wide-ranging in tastes, interests, or the like; having sympathies with all; broad-minded; liberal.
2. universal in extent; involving all; of interest to all.
as opposed to the more specific meaning of
3. pertaining to the whole Christian body or church
Likewise, the couple of significant turbulence exposures I've had were enough to give me a healthy interest in avoiding the next opportunity to sample Mother Nature's talents ..
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I've made a number of trips in the jumpseat on MD-80s in past years in the heavily traveled LAX-SFO corridor. While 727 crews were reporting enough turb to request altitude changes, we were feeling and reporting light chop.
Maybe the distance from the cockpit to the cg was a big factor, and maybe in some a/c turbulence can be aggravated by the autopilot.
GB
Maybe the distance from the cockpit to the cg was a big factor, and maybe in some a/c turbulence can be aggravated by the autopilot.
GB
Thread Starter
Execellent use of the word John! My parents has an incredibly broad vocabulary and this was one that they used on rare occasions as you did. Geekish? Not at all! It is refreshing to see it so employed!
Good discussion going on here!
Good discussion going on here!
Last edited by Uncle Fred; 27th Sep 2009 at 19:32.
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Support the one severe event in 10,000 hours theory (one in 12,000 for me).That was going into Hannover on one of those rare occasions when a super cell formed over Europe (isol cb was the forecast)!! All airfields within 50 miles were closed.CAT prevented us reading instruments..the dirt from the floor was on the roof...then in your hair. Without the inertia reel lock would have needed the bone dome someone mentioned earlier. Had to get the aircraft checked to make sure we had not exceeded any limits.
Not long after this I came across the met definitions of turbulence and they referred to pitch attitiude, airspeed fluctuations , height changes etc for each. Don't remember where I found it.If can help you please post it because I too have had many guys and girls confusing no sig turb with moderate and light with severe.
Not long after this I came across the met definitions of turbulence and they referred to pitch attitiude, airspeed fluctuations , height changes etc for each. Don't remember where I found it.If can help you please post it because I too have had many guys and girls confusing no sig turb with moderate and light with severe.
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.......yip, I'd have to agree with the 1 in 10,000hours opinion.
Eastbound, abeam Halifax, Nova Scotia, severe was forecast on all tracks.
Had a level lower than original flight plan in order to increase our G margin.
Was I glad I had that "extra bit"!
Had abrupt changes in vertical speed from+2500' per minute, to -2500', or even +-3,000fpm.Altitude changed by up to 350 to 400'. Airspeed + - 20 or so knots...workit out for your self what the change in Mach No. was, and the obvious benefit in the extra margin!
It lasted for 10 minutes, and for about 8 of that it was severe, and reported by us as such.
The aircraft coped with it surprisingly well, though. Autopilot did'nt disconnect, but autothrust performance was poor, and this was manually handled.
Anybody got an idea what the A320 is like in severe?
Eastbound, abeam Halifax, Nova Scotia, severe was forecast on all tracks.
Had a level lower than original flight plan in order to increase our G margin.
Was I glad I had that "extra bit"!
Had abrupt changes in vertical speed from+2500' per minute, to -2500', or even +-3,000fpm.Altitude changed by up to 350 to 400'. Airspeed + - 20 or so knots...workit out for your self what the change in Mach No. was, and the obvious benefit in the extra margin!
It lasted for 10 minutes, and for about 8 of that it was severe, and reported by us as such.
The aircraft coped with it surprisingly well, though. Autopilot did'nt disconnect, but autothrust performance was poor, and this was manually handled.
Anybody got an idea what the A320 is like in severe?
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Shy Talk,
Better still to report it accurately...it is only subjective if you don't have the definitions (which is why I'm hoping someone can dig them out). If a change in airspeed of 1 or 2 knots / change in altitude / pitch so small it barely registers (and the equivalent turbulence associated with these indications) get reported as severe then that is a problem. Yes I have had it and it undermines the credibility of in flight reports. If it became widespread then some could become complacent. You may remember the Ansett Capt who switched off the seatbelt sign when severe turbulence was forecast (happened about six months before they went belly up). A pax broke his neck ...paralysed for life...and he sued both the Capt and the Airline (Skipper lost his job).
Better still to report it accurately...it is only subjective if you don't have the definitions (which is why I'm hoping someone can dig them out). If a change in airspeed of 1 or 2 knots / change in altitude / pitch so small it barely registers (and the equivalent turbulence associated with these indications) get reported as severe then that is a problem. Yes I have had it and it undermines the credibility of in flight reports. If it became widespread then some could become complacent. You may remember the Ansett Capt who switched off the seatbelt sign when severe turbulence was forecast (happened about six months before they went belly up). A pax broke his neck ...paralysed for life...and he sued both the Capt and the Airline (Skipper lost his job).
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May I quote the following description of severe turbulence offered by an unknown pilot and mentioned in ""Handling The Big Jets" by D.P Davies. His book first published in April 1967 remains the finest yet I have read on jet flying. Yet from my experience very few of today's current airline pilots have ever read it - even though it is still available in most pilot shops. The chapter is No 8 and the title of the chapter "Flight Through Severe Weather." It says, quote:
"We encountered the most violent jolt I have ever experienced in over 20,000 hours of flying.
I felt as though an extremely severe positive, upward acceleration had triggered off a buffetting, not a pitch, that increased in frequency and magnitude as one might expect to encounter sitting on the end of a huge tuning fork that had been struck violently.
Not an instrument on any panel was readable to their full scale but appeared as white blurs against their dark background.
From that point on, it could have been 10, 20, 60 or 100 seconds, we had no idea of attitude, altitude, airspeed or heading. We were now on instruments with no visual reference and continued with severe to violent buffetting, ripping, tearing, rending crashing sounds. Briefcases, manuals, ashtrays, suitcases, pencils, cigarettes, flahlights flying around like unguided misslies. It sounded and felt as if the pods were leaving and the structure disintegrating.
The objects that were thrashing around the cockpit seemed to mementarily settle on the ceiling which made it impossible to trust one's senses - although I had a feeling we were inverted as my seat belt was tight and had stretched considerably. As my briefcase was on the ceiling, I looked up and through the overhead (eyebrow) window and felt that I was looking down on the top of a cloud deck. The first officer said later he had the same impression at the same instant we acted in unison applying as much force as we could gather to roll aileron control to the left.
The horizon bar at this time started to stabilise and showed us coming back through 90 degrees vertical to a level attitude laterally. At this time, I had my first airspeed reading decaying through 250 knots. The air smoothed out and we gently levelled off at between 1400 - 1500 feet...."
Unquote.
Hard to imagine after reading that, that some airlines do not allow unusual attitude recovery training in the simulator on the grounds that it will never happen. Reading from that extract from an airline pilot's report, it is obvious that instrument interpretation played a vital part in the recovery. Even a Microsoft PC Flight Simulator will allow instrument interpretation skills related to unusual attitudes to be practiced.
"We encountered the most violent jolt I have ever experienced in over 20,000 hours of flying.
I felt as though an extremely severe positive, upward acceleration had triggered off a buffetting, not a pitch, that increased in frequency and magnitude as one might expect to encounter sitting on the end of a huge tuning fork that had been struck violently.
Not an instrument on any panel was readable to their full scale but appeared as white blurs against their dark background.
From that point on, it could have been 10, 20, 60 or 100 seconds, we had no idea of attitude, altitude, airspeed or heading. We were now on instruments with no visual reference and continued with severe to violent buffetting, ripping, tearing, rending crashing sounds. Briefcases, manuals, ashtrays, suitcases, pencils, cigarettes, flahlights flying around like unguided misslies. It sounded and felt as if the pods were leaving and the structure disintegrating.
The objects that were thrashing around the cockpit seemed to mementarily settle on the ceiling which made it impossible to trust one's senses - although I had a feeling we were inverted as my seat belt was tight and had stretched considerably. As my briefcase was on the ceiling, I looked up and through the overhead (eyebrow) window and felt that I was looking down on the top of a cloud deck. The first officer said later he had the same impression at the same instant we acted in unison applying as much force as we could gather to roll aileron control to the left.
The horizon bar at this time started to stabilise and showed us coming back through 90 degrees vertical to a level attitude laterally. At this time, I had my first airspeed reading decaying through 250 knots. The air smoothed out and we gently levelled off at between 1400 - 1500 feet...."
Unquote.
Hard to imagine after reading that, that some airlines do not allow unusual attitude recovery training in the simulator on the grounds that it will never happen. Reading from that extract from an airline pilot's report, it is obvious that instrument interpretation played a vital part in the recovery. Even a Microsoft PC Flight Simulator will allow instrument interpretation skills related to unusual attitudes to be practiced.
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Better still to report it accurately...it is only subjective if you don't have the definitions (which is why I'm hoping someone can dig them out)
See: http://www.pprune.org/tech-log/38180...efinition.html
An excerpt from his/her original post:
"...However, I vaguely recall that it applied to "Transport Aircraft," and that the document classified turbulence somewhere around the following values:
- Light Chop = 5 – 14 knot changes in IAS
- Moderate Chop = 15-25 knot changes in IAS
- Light Turbulence = 5 – 14 knot changes in IAS, AND, 300 – 1199 FPM V/S
- Moderate Turbulence = 15-24 knot changes in IAS, AND, 1200 – 2400 FPM V/S
- Severe Turbulence = +25 knot changes in IAS, AND, 2500 - 2999 FPM V/S
- Extreme Turbulence = + 3000 FPM V/S...
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Had plenty of moderate and severe turbulence on a nimrod < 500' over the angry north atlantic but only a couple of moderate encounters in 5000 airline ops.
My "subjective" opinion of turbulence tends to classify it lower than most I've flown with in the airline world. I think rather than "momentary loss of control" the "objects being thrown around" and "impossible to walk around" statements are better gauges of severe turbulence. If stuff isn't flying around you are in no more than moderate according to the book.
My "subjective" opinion of turbulence tends to classify it lower than most I've flown with in the airline world. I think rather than "momentary loss of control" the "objects being thrown around" and "impossible to walk around" statements are better gauges of severe turbulence. If stuff isn't flying around you are in no more than moderate according to the book.