Crosswind Limits
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The value shown is not considered to be limiting.
DFC - so why would the lawyers add this in the POH?
An aircraft I fly is placarded to say I MUST NOT perform certain aerobatics if certain conditions are not met.
I can find no placard to say I MUST not land if the cross wind component is above a certain figure.
Why is there a placard for the first (and I might never fly aeros in the aircraft) but not for the second, given at the very least I am hopefully going to land after every flight.
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Fuji,
Do you know that the legal department added in that piece?
The placards in your aircraft are giverned by regulation - the certification standard and the mandatory ones will be listed in the Type Certificate Data Sheet.
You will find all the limits on the Type Certificate Dats Sheet.
You will not find the Stall Speeds there. Do you think that they are limiting in any way?
You will not find that airfeild performance figures there. Do they limit you in any way?
As I said near the start of the debate. Feel free to be a test pilot if you want. Check that test flying is permitted by the insurance policy because valid insurance is mandatory.
You might also like to check the legal conditions required for test flying especially the ones regarding the carriage of observers etc etc.
Regards,
DFC
Do you know that the legal department added in that piece?
The placards in your aircraft are giverned by regulation - the certification standard and the mandatory ones will be listed in the Type Certificate Data Sheet.
You will find all the limits on the Type Certificate Dats Sheet.
You will not find the Stall Speeds there. Do you think that they are limiting in any way?
You will not find that airfeild performance figures there. Do they limit you in any way?
As I said near the start of the debate. Feel free to be a test pilot if you want. Check that test flying is permitted by the insurance policy because valid insurance is mandatory.
You might also like to check the legal conditions required for test flying especially the ones regarding the carriage of observers etc etc.
Regards,
DFC
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That is opinion or speculation and is not based on any calculation demonstration or result.
Do you honestly think that nobody at Cessna would have flown the aircraft at higher x-wind speeds than the MDCV before making this statement in the POH ?
Honestly ? And you call me an idiot ?
FF
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Do you know that the legal department added in that piece?
Do you know they didnt? And if they didnt you bet they reviewed it. And if they didnt review it then they had better look out.
and 2wit, as you know, no one is saying you should NOT stall most GA types, otherwise that would be one less task for the flight trainers.
.. .. .. and so back to which, since it would seem clear most manufacturers
are able to grasp the use of plain English by virtue of being happy to liberally sprinkle the POH with "limiting" and "prohibited" and such other clear wording I shall hold on to my belief that if they wished to limit me to their demonstrated component they would have said so - and that shall remain my defense!
Do you know they didnt? And if they didnt you bet they reviewed it. And if they didnt review it then they had better look out.
and 2wit, as you know, no one is saying you should NOT stall most GA types, otherwise that would be one less task for the flight trainers.
.. .. .. and so back to which, since it would seem clear most manufacturers
are able to grasp the use of plain English by virtue of being happy to liberally sprinkle the POH with "limiting" and "prohibited" and such other clear wording I shall hold on to my belief that if they wished to limit me to their demonstrated component they would have said so - and that shall remain my defense!
Moderator
Ok, As it appears that only DFC has really done his homework here, and understands where the term "demonstrated" originated, here's the standard:
3.145 Directional stability and control
(a) There shall be no uncontrollable looping tendency in 90-degree cross winds up to a velocity equal to 0.2 Vs0 at any speed at which the aircraft may be expected to be operated upon the ground or water.
(b) All landplanes shall be demonstrated to be satisfactorily controllable with no exceptional degree of skill or alertness on the part of the pilot in power-off landings at normal landing speed and during which brakes or engine power are not used to maintain a straight path.
(c) Means shall be provided for adequate directional control during taxiing.
So the aircraft manufacturer's lawyers are going to go to court and say "our test pilots did that, and here's the report." If the test pilots did more, and you can bet that they did, the manufacturer is not going to tell you that. There are lots of things they are not going to tel you.
Cessna used to produce a document called "Getting the maximum performance from a Cessna 150". I saw it once. Try to get a copy now!
My Cessna has a stated demonstrated crosswind value, which I'm sure meets the aforementioned standard. It also has an STC'd STOL kit, which very much changes low speed handling, and stall speed. That installation does not change the demonstrated crosswind capability value though, as no revised value is provided with the kit. (No Flight Manual Supplement or placard is provided, and that's the only way to convey changed information).
Manufacturer's and writers of design standards know that some pilots have more skill than others. They must account for the lowest common denominator of pilot skill sets in the standards. Hence demonstrating that the average skill set is enough to safely control the plane.
Sometimes when I have done modification design complaince evaluation flying for Transport Canada (I'm carefully not calling it test flying, Im not going to start that debate!) I wonder to myself if I am properly simulating average skill during cross wind work. If I apply a lot of effort to seeing what the aircraft can do, I may have gone beyond a demonstration of average skill.
Pilot DAR
3.145 Directional stability and control
(a) There shall be no uncontrollable looping tendency in 90-degree cross winds up to a velocity equal to 0.2 Vs0 at any speed at which the aircraft may be expected to be operated upon the ground or water.
(b) All landplanes shall be demonstrated to be satisfactorily controllable with no exceptional degree of skill or alertness on the part of the pilot in power-off landings at normal landing speed and during which brakes or engine power are not used to maintain a straight path.
(c) Means shall be provided for adequate directional control during taxiing.
So the aircraft manufacturer's lawyers are going to go to court and say "our test pilots did that, and here's the report." If the test pilots did more, and you can bet that they did, the manufacturer is not going to tell you that. There are lots of things they are not going to tel you.
Cessna used to produce a document called "Getting the maximum performance from a Cessna 150". I saw it once. Try to get a copy now!
My Cessna has a stated demonstrated crosswind value, which I'm sure meets the aforementioned standard. It also has an STC'd STOL kit, which very much changes low speed handling, and stall speed. That installation does not change the demonstrated crosswind capability value though, as no revised value is provided with the kit. (No Flight Manual Supplement or placard is provided, and that's the only way to convey changed information).
Manufacturer's and writers of design standards know that some pilots have more skill than others. They must account for the lowest common denominator of pilot skill sets in the standards. Hence demonstrating that the average skill set is enough to safely control the plane.
Sometimes when I have done modification design complaince evaluation flying for Transport Canada (I'm carefully not calling it test flying, Im not going to start that debate!) I wonder to myself if I am properly simulating average skill during cross wind work. If I apply a lot of effort to seeing what the aircraft can do, I may have gone beyond a demonstration of average skill.
Pilot DAR
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Limits and otherwise
Look, this is all much simpler than is being argued.
The design approval of an aeroplane requires certain facts to be established. Hopefully someone will find the actual design regulations and link them here, it has been found before but some time ago.
The Demonstrated Crosswind Component is not an actual flown exercise but a mathmatical calculation based on designed control available. It is generally understood that this calculation demonstrates that an average pilot in reasonable practice should be able to control the aircraft safely when landing. The italics are not the regulation but how they might reasonably be interpreted. However these calculations are only one part of a scenario where many other factors may be dominent such as pilot ability and other considerations pertaining at the time. This is usually the case with light aircaft and therefore it would be impossible to define a limit. I'm sure that there are light aircraft with a crosswind defined limit, just the same.
A limit is normally applied to larger heavy aircraft (although not only) when beyond such a limit, control of the aircraft is unlikely irrespective of the pilots ability. This could be say a limit on the maximum angle of bank during landing owing to the fact that the wing tip, engine nacelle or propellor could strike the ground. There will be various reasons but i'm sure it is obvious that with the above restrictions the pilots choices are 'limited' and so therefore is the maximum crosswind.
The design approval of an aeroplane requires certain facts to be established. Hopefully someone will find the actual design regulations and link them here, it has been found before but some time ago.
The Demonstrated Crosswind Component is not an actual flown exercise but a mathmatical calculation based on designed control available. It is generally understood that this calculation demonstrates that an average pilot in reasonable practice should be able to control the aircraft safely when landing. The italics are not the regulation but how they might reasonably be interpreted. However these calculations are only one part of a scenario where many other factors may be dominent such as pilot ability and other considerations pertaining at the time. This is usually the case with light aircaft and therefore it would be impossible to define a limit. I'm sure that there are light aircraft with a crosswind defined limit, just the same.
A limit is normally applied to larger heavy aircraft (although not only) when beyond such a limit, control of the aircraft is unlikely irrespective of the pilots ability. This could be say a limit on the maximum angle of bank during landing owing to the fact that the wing tip, engine nacelle or propellor could strike the ground. There will be various reasons but i'm sure it is obvious that with the above restrictions the pilots choices are 'limited' and so therefore is the maximum crosswind.
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DAR,
Is there an equivalent standard for "x-wind LIMIT" ?
I think you're missing the point. The definition of the word "demonstrated" is not the issue : what is being argued over is whether operating an aircraft beyond its demonstrated x-wind value is illegal by virtue of the fact that to do so instantly makes you a test-pilot and therefore invalidates your insurance (and makes your under-carriage fall off, evidently ...)
My argument is that if Mr. Cessna says that the MDCV "is not considered to be limiting", then he's saying that because his designers and test pilots have already proven this to be the case.
If I attempt to land with a ridiculous amount of x-wind and the wheels snap off, I'd expect to have a problem with my insurers. However, if the same thing happened a couple of knots over the MDCV, with the protection of that statement in my POH I'd be quite happy to pursue a claim.
In short, if they meant "limit", they'd say so ...
FF
Is there an equivalent standard for "x-wind LIMIT" ?
I think you're missing the point. The definition of the word "demonstrated" is not the issue : what is being argued over is whether operating an aircraft beyond its demonstrated x-wind value is illegal by virtue of the fact that to do so instantly makes you a test-pilot and therefore invalidates your insurance (and makes your under-carriage fall off, evidently ...)
My argument is that if Mr. Cessna says that the MDCV "is not considered to be limiting", then he's saying that because his designers and test pilots have already proven this to be the case.
If I attempt to land with a ridiculous amount of x-wind and the wheels snap off, I'd expect to have a problem with my insurers. However, if the same thing happened a couple of knots over the MDCV, with the protection of that statement in my POH I'd be quite happy to pursue a claim.
In short, if they meant "limit", they'd say so ...
FF
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DAR and FF
Actually FF I think it was a good post but for a different reason.
It brings home the key point on an interesting and very old debate.
For commercial ops it can be assumed that all pilots will perform to a given standard. In short a limit can be imposed because there is a reasonable possibility you will bend it if you go beyond the limit.
In GA the product liability lawyers learnt long ago that many of their customers really havent got a clue what they are doing. Consequently they are not going to tell you what the limit is, becasue many will try it and regret they did. However, what they will tell you is what a reasonably ham fisted pilot is likely to be able to get away with.
So as my final contribution on this one, I think how the number is derived is well known (to those on here at any rate), and I have seen absolutely nothing to convince me that it is in any way intended to be a limit.
(Sorry to disappoint you DFC - I respect the points you have made, I just dont agree with them)
Actually FF I think it was a good post but for a different reason.
It brings home the key point on an interesting and very old debate.
For commercial ops it can be assumed that all pilots will perform to a given standard. In short a limit can be imposed because there is a reasonable possibility you will bend it if you go beyond the limit.
In GA the product liability lawyers learnt long ago that many of their customers really havent got a clue what they are doing. Consequently they are not going to tell you what the limit is, becasue many will try it and regret they did. However, what they will tell you is what a reasonably ham fisted pilot is likely to be able to get away with.
So as my final contribution on this one, I think how the number is derived is well known (to those on here at any rate), and I have seen absolutely nothing to convince me that it is in any way intended to be a limit.
(Sorry to disappoint you DFC - I respect the points you have made, I just dont agree with them)
Formerly HWD
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Homeguard,
I disagree. My understanding is that the demonstrated crosswind is simply that which was observed by the certifying authority during flight testing for certification. I'm sure there are certain minimum crosswind capabilities that are mathematically built in at design time, like the FAA required 0.2Vso for example (something like that anyway). But I don't believe the demonstrated one is a limit unless somebody decides to make it so (A flying club's regulations for example). I certainly don't suggest anybody tries it, but I am sure I am not alone, I am sure there are many PA28 and C152 pilots out there who have landed in crosswinds several knots in excess of the demonstrated without any difficulties.
Now the PA17 on the other hand...well my limit is somewhat lower
The Demonstrated Crosswind Component is not an actual flown exercise but a mathmatical calculation based on designed control available.
Now the PA17 on the other hand...well my limit is somewhat lower
There is little mystery about how this number is determined:
AC23-8B FLIGHT TEST GUIDE FOR CERTIFICATION OF PART 23 AIRPLANES.
107. SECTION 23.233 DIRECTIONAL STABILITY AND CONTROL.
a. Explanation.
(1) Crosswind. This regulation establishes the minimum value of crosswind that must be demonstrated. Since the minimum required value may be far less than the actual capability of the airplane, higher values may be tested at the option of the applicant. The highest 90-degree crosswind component tested satisfactorily should be put in the AFM as performance information. If a demonstrated crosswind is found limiting, it has to be introduced in Section 2 of the AFM.
...
b. Procedures.
(1) Crosswind.
(a) The airplane should be operated throughout its approved loading envelope at gradually increasing values of crosswind component until a crosswind equivalent to 0.2 VSO is reached. All approved takeoff and landing configurations should be evaluated. Higher crosswind values may be evaluated at the discretion of the test pilot for AFM inclusion.
It would be difficult to be more explicit about whether the vaalue is limiting or not, wouldn't it?
AC23-8B FLIGHT TEST GUIDE FOR CERTIFICATION OF PART 23 AIRPLANES.
107. SECTION 23.233 DIRECTIONAL STABILITY AND CONTROL.
a. Explanation.
(1) Crosswind. This regulation establishes the minimum value of crosswind that must be demonstrated. Since the minimum required value may be far less than the actual capability of the airplane, higher values may be tested at the option of the applicant. The highest 90-degree crosswind component tested satisfactorily should be put in the AFM as performance information. If a demonstrated crosswind is found limiting, it has to be introduced in Section 2 of the AFM.
...
b. Procedures.
(1) Crosswind.
(a) The airplane should be operated throughout its approved loading envelope at gradually increasing values of crosswind component until a crosswind equivalent to 0.2 VSO is reached. All approved takeoff and landing configurations should be evaluated. Higher crosswind values may be evaluated at the discretion of the test pilot for AFM inclusion.
It would be difficult to be more explicit about whether the vaalue is limiting or not, wouldn't it?
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3.145 Directional stability and control
(a) There shall be no uncontrollable looping tendency in 90-degree cross winds up to a velocity equal to 0.2 Vs0 at any speed at which the aircraft may be expected to be operated upon the ground or water.
(a) There shall be no uncontrollable looping tendency in 90-degree cross winds up to a velocity equal to 0.2 Vs0 at any speed at which the aircraft may be expected to be operated upon the ground or water.
In my machines case this is barely 5kts, and would hardly be noticeable. In practice (and backed up by some of the claims on here) a value of 0.3 - 0.4 would be more realistic. Or in the case of Chuck Ellsworth's Dakota 1.0!!
I really wonder if I shouldn't give up flying until such time as scientists can control the weather, or every airfield has multiple runways.
Formerly HWD
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I understand that the 0.2Vso limit is only the minimum using only aerodynamic controls, I don't think this infers anything else.
Higher values maybe quoted if demonstrated. Where those higher values require the use of specific techniques, braking or engines to maintain control, those technique will be described in the flight manual.
Higher values maybe quoted if demonstrated. Where those higher values require the use of specific techniques, braking or engines to maintain control, those technique will be described in the flight manual.
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Where in the flght manual does it say that you have to hold a licence to fly the aircraft?
Indeed. And guess what the imposed crosswinf limit will be!!
bookworm has posted a very valuable quote;
This places it in the same category as airfield performance.
What will your insurance company say if you run into the hedge at the end of a 499m strip when the flight manual says you need 500m in the conditions?
Anyone who wants to use a crosswind higher than the manufacturer has demonstrated as being safe can do so any time they want. However, they simply have to be aware that if their insurance policy says no test flying then they are not covered.
They could always stand up in court after the accident and proudly tell the court that despite the damamged aircraft being evidence to the contrary, they are a pilot of above average ability........to the sound of "arrogant to$$3r" from everyone present.
----------
Pilot DAR,
Love it, Must remember that in future.
Regards,
DFC
For commercial ops it can be assumed that all pilots will perform to a given standard. In short a limit can be imposed because there is a reasonable possibility you will bend it if you go beyond the limit.
bookworm has posted a very valuable quote;
The highest 90-degree crosswind component tested satisfactorily should be put in the AFM as performance information
What will your insurance company say if you run into the hedge at the end of a 499m strip when the flight manual says you need 500m in the conditions?
Anyone who wants to use a crosswind higher than the manufacturer has demonstrated as being safe can do so any time they want. However, they simply have to be aware that if their insurance policy says no test flying then they are not covered.
They could always stand up in court after the accident and proudly tell the court that despite the damamged aircraft being evidence to the contrary, they are a pilot of above average ability........to the sound of "arrogant to$$3r" from everyone present.
----------
Pilot DAR,
design complaince evaluation flying
Regards,
DFC
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Is Beagle still about?
He IS a test pilot isn't he? sounds like a good source for an authroritive answer.
I've managed 28G38 at 80deg in a C150. With the instant wind at the top of that as I came over the threshold.
Piece of cake, and I'm sure no problem for the insurers if you come into difficulties..
He IS a test pilot isn't he? sounds like a good source for an authroritive answer.
I've managed 28G38 at 80deg in a C150. With the instant wind at the top of that as I came over the threshold.
Piece of cake, and I'm sure no problem for the insurers if you come into difficulties..
Fly Conventional Gear
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This places it in the same category as airfield performance.
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I said I wasnt going to post again - and it really really is my last, but I always worry about insurance issues.
Anyway I emailed my insurers to ask whether they would settle a claim if the aircraft landed in a cross wind more than the demonstrated cross wind component in the POH and in consequence was damaged.
They said they would.
In fact they have just 'phoned to say they wondered whether an accident had actually occurred. I told them it had not but thanked them for their concern. We chatted and I pointed them to this thread which he had actually been reading. He laughed, said so far as they were concerned the whole thing was totally ridiculous and they had all had a chuckle. He made one or two other amusing comments.
It has put my mind at rest so far as the insurance issue was concerned.
I appreciate other insureres may take a different view.
Anyway I emailed my insurers to ask whether they would settle a claim if the aircraft landed in a cross wind more than the demonstrated cross wind component in the POH and in consequence was damaged.
They said they would.
In fact they have just 'phoned to say they wondered whether an accident had actually occurred. I told them it had not but thanked them for their concern. We chatted and I pointed them to this thread which he had actually been reading. He laughed, said so far as they were concerned the whole thing was totally ridiculous and they had all had a chuckle. He made one or two other amusing comments.
It has put my mind at rest so far as the insurance issue was concerned.
I appreciate other insureres may take a different view.
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Bookworm :
Absolutely.
Anyway, that's me out of this thread until/if Cessna reply to the letter I've sent. It's absolutely pointless trying to debate with someone like DFC who is willing to only quote the parts of a post which suit his purpose whilst ignoring the rest :-
Mass weapons of destruction in 45 mins, anyone ? 
However, if anyone has any actual knowledge of any prosecution where a pilot has been done for exceeding a demo'd x-wind value - in an aircraft where the POH does NOT state the value to be limiting - I'd be interested in hearing it ?
Edited to add : Fuji, thanks for doing that. You will have set a lot of people's minds at rest - good for you !
FF
It would be difficult to be more explicit about whether the vaalue is limiting or not, wouldn't it?
Anyway, that's me out of this thread until/if Cessna reply to the letter I've sent. It's absolutely pointless trying to debate with someone like DFC who is willing to only quote the parts of a post which suit his purpose whilst ignoring the rest :-
If a demonstrated crosswind is found limiting, it has to be introduced in Section 2 of the AFM.
However, if anyone has any actual knowledge of any prosecution where a pilot has been done for exceeding a demo'd x-wind value - in an aircraft where the POH does NOT state the value to be limiting - I'd be interested in hearing it ?
Edited to add : Fuji, thanks for doing that. You will have set a lot of people's minds at rest - good for you !
FF
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They said they would.......have just 'phoned to say they wondered whether an accident had actually occurred.
Upto The Buffers
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Fuji, thanks for posting that which was what I was originally trying to get at. Mine have said the same, but as with many things in aviation the facts (as opposed to the folklore) appears to have got long since lost amongst the clubhouse bullsh!t, along with IMC-rating approach minima I presume...