Demonstrated X wind a pointless figure ?
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I am sick and tired of idiots such as Genghis, so this is the last time I read or post here in PPRuNe, have a nice life.
I note that others have taken you to task over this comment .. surely you were being somewhat tongue-in-cheek ?
If not, it's not too difficult to divine who Genghis is and what his considerable background entails ... not a chap to whom one might apply your comment, methinks ..
There was a query re upgrading crosswind figures and I don't think I saw a response ? Certainly no reason why the OEM data can't be revisited if required .. we have done so on a number of occasions in Oz .. the only time we frightened ourselves was with the small Rockwell singles .. as I recall they have an aileron/rudder interconnect which does provide a real limit not very many knots above the OEM figure ..
I note that others have taken you to task over this comment .. surely you were being somewhat tongue-in-cheek ?
If not, it's not too difficult to divine who Genghis is and what his considerable background entails ... not a chap to whom one might apply your comment, methinks ..
There was a query re upgrading crosswind figures and I don't think I saw a response ? Certainly no reason why the OEM data can't be revisited if required .. we have done so on a number of occasions in Oz .. the only time we frightened ourselves was with the small Rockwell singles .. as I recall they have an aileron/rudder interconnect which does provide a real limit not very many knots above the OEM figure ..
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I am sick and tired of idiots such as Genghis, so this is the last time I read or post here in PPRuNe, have a nice life.
Pace
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the only time we frightened ourselves was with the small Rockwell singles .. as I recall they have an aileron/rudder interconnect which does provide a real limit not very many knots above the OEM figure ..
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There are times when the male of the species feels challenged and rather than decking the challenger, throws his toys out of the pram and stalks off in a huff. As we were discussing crosswind limits in this thread, it reminds me of a very very strong wind day at the gliding club. The pilot who had actually introduced me to the art of airtowing gliders with my Supercub, was flying on this day. Watching from the sidelines with alarm, I saw him landing on the crosswind runway, with the towrope attached, scooting over to the next glider, and taking off. With great skill and experience, of course.
The crosswind limits for my PA18 Supercub in the pilot's operating handbook state the limits as 10 miles an hour.
So concerned for my precious Cub, after its next hairy arrival on the crosswind runway, I went over and tapped on his window. Could you possibly, I suggested, land on the intowind runway? you can always drop the towrope first...."
Said he "If you don't like the way I fly it, you can take over! ! ! ! !" so saying he yanked his headset out of the panel, climbed out and stalked off, never to be seen again that day. Ooops!
So I climbed into my beloved Cub, hooked up to the next glider, and took off. After he was away, I dropped the rope in a safe place, and landed on the intowind run. At an airspeed of 40 knots, we were STATIONAIRY OVER THE GROUND. Forget this for a mugs game, I know when to quit! So I didn't even TRY to turn and taxi back, just sat there in the way, until enough heavy manly bodies showed up to push the Supercub backwards into the hangar. If anybody wanted a launch after that, they had to go up the wire.
The crosswind limits for my PA18 Supercub in the pilot's operating handbook state the limits as 10 miles an hour.
So concerned for my precious Cub, after its next hairy arrival on the crosswind runway, I went over and tapped on his window. Could you possibly, I suggested, land on the intowind runway? you can always drop the towrope first...."
Said he "If you don't like the way I fly it, you can take over! ! ! ! !" so saying he yanked his headset out of the panel, climbed out and stalked off, never to be seen again that day. Ooops!
So I climbed into my beloved Cub, hooked up to the next glider, and took off. After he was away, I dropped the rope in a safe place, and landed on the intowind run. At an airspeed of 40 knots, we were STATIONAIRY OVER THE GROUND. Forget this for a mugs game, I know when to quit! So I didn't even TRY to turn and taxi back, just sat there in the way, until enough heavy manly bodies showed up to push the Supercub backwards into the hangar. If anybody wanted a launch after that, they had to go up the wire.
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Mary I love reading all about your adventures and experiences.
The beauty of private flying is that it is for enjoyment and the guy/gal spending their hard earned money can close the curtains and go back to sleep to await a better day.
Slightly different for those who have to fly (within reason) Where you pull back the curtains to see a dark night, strong winds and driving rain and take off into that with your brain still wanting to be curled up in bed
Pace
The beauty of private flying is that it is for enjoyment and the guy/gal spending their hard earned money can close the curtains and go back to sleep to await a better day.
Slightly different for those who have to fly (within reason) Where you pull back the curtains to see a dark night, strong winds and driving rain and take off into that with your brain still wanting to be curled up in bed
Pace
** student alert **
As a student I'm seeing it as the "really think about it seriously number". In fact I scrubbed a lesson last week, the instructor said we could fly, but he might need to do the landing, and at the minute I am training my brain to say "no" sometimes, which isn't easy when you're a student.
My view, when it's slightly over the POH speed for a C152, its still flyable, just not for me with my level of skill right now.
As a student I'm seeing it as the "really think about it seriously number". In fact I scrubbed a lesson last week, the instructor said we could fly, but he might need to do the landing, and at the minute I am training my brain to say "no" sometimes, which isn't easy when you're a student.
My view, when it's slightly over the POH speed for a C152, its still flyable, just not for me with my level of skill right now.
To return to the subject of crosswind limits.
Having just retired after forty six years of flying my understanding is simply this.
The demonstrated cross wind component is only that supplied by the manufacturer given the actual conditions used to achieve what they thought a useful limit might be. They could have spent more time and effort achieving a higher one but chose not to do so. It is what it says, a demonstrated wind that may not be limiting.
The aircraft operator and/or owner may then set a limit based on this figure that any operating pilot would have to adhere to.
The reason that the figure becomes binding is simply that if you have an accident or incident the insurance company can (and in my experience will) have perfect reason not to pay out, to either the operator or third parties. Saying to them that there was no set limit will not work. In the absence of an operators limit the insurers will use the flight manual demonstrated component to get out of paying.
Having just retired after forty six years of flying my understanding is simply this.
The demonstrated cross wind component is only that supplied by the manufacturer given the actual conditions used to achieve what they thought a useful limit might be. They could have spent more time and effort achieving a higher one but chose not to do so. It is what it says, a demonstrated wind that may not be limiting.
The aircraft operator and/or owner may then set a limit based on this figure that any operating pilot would have to adhere to.
The reason that the figure becomes binding is simply that if you have an accident or incident the insurance company can (and in my experience will) have perfect reason not to pay out, to either the operator or third parties. Saying to them that there was no set limit will not work. In the absence of an operators limit the insurers will use the flight manual demonstrated component to get out of paying.
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The demonstrated cross wind component is only that supplied by the manufacturer given the actual conditions used to achieve what they thought a useful limit might be.
If an aircraft operator were to "set" a different value, that would be their choice, but probably arbitrary, and difficult to support with test data. But yes, I can see value in telling new solo students that a given crosswind was too strong. That would not be because of the aircraft, but rather that that new pilot had not yet achieved the standard of "average pilot skill" stated in the design requirement. Otherwise, the value in the flight manual would seem to be a great reference for the average pilot of the aircraft. I cannot see a reason why an operator would state a greater value, just be silent on that.
The design requirements to which the plane was certified overtly do not prohibit operations in stronger crosswinds. I opine that this would be because the regulator or manufacturer logically do not want to tell a pilot that they cannot land a plane legally - 'cause it's going to happen before or at the end of the fuel! As a regulator, I would much rather that the interpretation by the pilot results in them going off the side of a runway due to too strong a wind during a landing attempt, than a crash off airport because they thought that a landing attempt there would be prohibited. Obviously, a nearby airport with a different runway orientation would be preferable - if there is one. But I have certainly flown to one runway airports where the actual crosswind was stronger than forecast, and the next nearest runway was hundreds of miles away! You're landing on that runway or none at all!
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Saying to them that there was no set limit will not work. In the absence of an operators limit the insurers will use the flight manual demonstrated component to get out of paying.
Bose. My own experience of seeing the insurance industry at work both on other peoples accidents and an incident of my own a few years ago forms the basis of my statement.
It is true that the insurance industry are not legally able to state that the demonstrated crosswind is limiting. But they do expect the owner/operator to operate inside the aircrafts flight manual which equates to much the same thing. It would be a brave operator who specified a higher limit than that demonstrated.
You would be perfectly entitled to challenge the insurance company in court on the matter but the cost would probably outweigh the value of the aircraft many times over.
The original question was whether the flight manual figure is limiting or not. No. It isn't but you'd be a brave man to stand up from the wreckage and say you were in the right. Stick to the figure or land uninsured, that may not be the legal position but it's the best advice.
It is true that the insurance industry are not legally able to state that the demonstrated crosswind is limiting. But they do expect the owner/operator to operate inside the aircrafts flight manual which equates to much the same thing. It would be a brave operator who specified a higher limit than that demonstrated.
You would be perfectly entitled to challenge the insurance company in court on the matter but the cost would probably outweigh the value of the aircraft many times over.
The original question was whether the flight manual figure is limiting or not. No. It isn't but you'd be a brave man to stand up from the wreckage and say you were in the right. Stick to the figure or land uninsured, that may not be the legal position but it's the best advice.
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But this is the problem and maybe why I posted this topic for discussion. The FM is full of limiting speeds which are accurately worked out with a margin of safety built in.
I am sure most of us have seen pilots who are not the best in the world drop the gear above its extension speed or put flaps in above their extension or retraction speeds?
Nothing happens because the manufacturers accept human error and allow a margin
Demonstrated is not a limiting number and very unscientific. You might as well pick it out of a hat.
I cannot remember off hand what the Seneca Five demonstrated was but probably around 15 KTS I know the reality is around 38 KTS direct steady crosswind a huge difference.
Why not like any other limiting speed work it out put in a safety margin and have that as a realistic limiting speed rather than letting pilots work out their own because some test pilot says he has demonstrated the aircraft in 5 KTS 10 KTS 15 KTS etc its meaningless.
I also cannot see how a demonstrated figure could be used in a court of law as a limiting figure because even in the manual its described as demonstrated and in no way limiting which most figures are?
No manufacturer is going to stand in court and claim this figure as a limiting figure which the pilot exceeded.
What are you going to do in a court of law? argue whether the pilot is below average, average or a top gun ? or divert because the given wind is 16 KTS instead of 15KTS ?
Pace
But this is the problem and maybe why I posted this topic for discussion. The FM is full of limiting speeds which are accurately worked out with a margin of safety built in.
I am sure most of us have seen pilots who are not the best in the world drop the gear above its extension speed or put flaps in above their extension or retraction speeds?
Nothing happens because the manufacturers accept human error and allow a margin
Demonstrated is not a limiting number and very unscientific. You might as well pick it out of a hat.
I cannot remember off hand what the Seneca Five demonstrated was but probably around 15 KTS I know the reality is around 38 KTS direct steady crosswind a huge difference.
Why not like any other limiting speed work it out put in a safety margin and have that as a realistic limiting speed rather than letting pilots work out their own because some test pilot says he has demonstrated the aircraft in 5 KTS 10 KTS 15 KTS etc its meaningless.
I also cannot see how a demonstrated figure could be used in a court of law as a limiting figure because even in the manual its described as demonstrated and in no way limiting which most figures are?
No manufacturer is going to stand in court and claim this figure as a limiting figure which the pilot exceeded.
What are you going to do in a court of law? argue whether the pilot is below average, average or a top gun ? or divert because the given wind is 16 KTS instead of 15KTS ?
Pace
Last edited by Pace; 5th Feb 2016 at 17:59.
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The system is stupid and a 'limit' should be stipulated.
It sure could create an awkward situation if a pilot, upon reaching their destination, found a crosswind exceeding the "limit". If there is no alternative runway, what is the pilot to do? Orbit until it abates? Consider flying a route along which the runways are several hundred miles apart from each other. You're going to fly an hour or two back because a reported wind value exceeds a limit? If there were only a wind sock at the aerodrome, and no speed information, how would the pilot know that a landing was permissible? You've flown a nervous hour over the mountains, or open water, and now you're going to take that risk all again, with much less fuel because a crosswind is reported above a limit?
I believe that the regulators have thought this through, and got it right.
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If I remember rightly, there were experiments in WWII on the feasibility of castering mainwheels - I believe up to a C-47 (but have no refernces).
This seems (to a very old tail-dragger who has long and bitter memories of crosswinds) to be the obvious solution to an enduring problem.
Moonshine ? Not so, see:
VIDEO: This is How A B-52H Lands in a Crosswind And Stays Completely Sideways While Deploying A Parachute and Slowing Down On The Runway - Skilled Pilots - Aviation Blog and Community
Danny42C.
This seems (to a very old tail-dragger who has long and bitter memories of crosswinds) to be the obvious solution to an enduring problem.
Moonshine ? Not so, see:
VIDEO: This is How A B-52H Lands in a Crosswind And Stays Completely Sideways While Deploying A Parachute and Slowing Down On The Runway - Skilled Pilots - Aviation Blog and Community
Danny42C.
Didn't an early Cessna taildragger have this, at least as an option? Manhandling into the hangar was difficult. As a taildragger pilot frequently landing a Jodel DR1050 on a wide, long, tarmac runway in gusty crosswinds, the idea of having castoring main wheels after a crosswind touchdown is a worse nightmare than anything I've ever dreamt.
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the idea of having castoring main wheels after a crosswind touchdown is a worse nightmare than anything I've ever dreamt.
A lack of consistency in the wind strength and direction horizontally and vertically not just how much is coming from the side which to a certain extent is governed by the amount of rudder authority which again is related to the speed the pilot lands at
There the pilot has to be able to adjust to those changing conditions or even make a decision to go around if he/she is not happy
It still all comes back to technique and decision making surely? Sometimes I wonder whether rather than demonstrated the test pilot asses the aircraft ability to handle crosswinds and instead uses a grading from Good to medium good to average to medium poor or poor and not fix an out of the hat number at all
Last edited by Pace; 6th Feb 2016 at 11:02.
That is actually what Test Pilots often do - the Cooper Harper pilot compensation scale uses scores from 1 (aeroplane does it on its own ) to 10 (totally uncontrollable ) for whatever aspect of handling is being assessed.
It's just that that information is never mapped into the manuals beyond that a 5 is about where you'd probably set the limits.
G
It's just that that information is never mapped into the manuals beyond that a 5 is about where you'd probably set the limits.
G
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Is the limit actually known by the manufacturers?
As it would seem to be fairly easily worked out on a test bed in a wind tunnel increasing a direct crosswind till there was no more control authority on the controls and setting a figure back from there?
Pace
Is the limit actually known by the manufacturers?
As it would seem to be fairly easily worked out on a test bed in a wind tunnel increasing a direct crosswind till there was no more control authority on the controls and setting a figure back from there?
Pace