Max Cross wind
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Max Cross wind
Hi all,
just a brief one...
When you have a crosswind limit of 24 knots, and you have a wind from 90 degrees off with 20 knots gusting 30 knots.
Is this in limits?
Meaning, what is the limit? The steady wind or the gust?
Thanks for help!
just a brief one...
When you have a crosswind limit of 24 knots, and you have a wind from 90 degrees off with 20 knots gusting 30 knots.
Is this in limits?
Meaning, what is the limit? The steady wind or the gust?
Thanks for help!
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I was always told "Land it during a lull in the wind!" but I don't think that really helps.
My understanding is that the wind for your landing is considered to be whatever the last windcheck was that you got. This is similar to the RVR issue. Once you've received an RVR report which is above minima you'd better hope that they don't report another one.
The other part to my answer is this. Most (all?) Pilot Operating Handbooks state a maximum demonstrated crosswind. That's the most that the manufacturer managed to demonstrate that the aircraft can land in. If, during the certification, they didn't have any windy days then they can only give the max crosswind that they managed to demonstrate. The C152 is a prime example. It's max demonstrated crosswind is 12 knots. I (along with many others) have demonstrated that it can land in more than twice that much. But it's what the manufacturer managed to demonstrate that counts for the book.
Finally you have to ask yourself what the lawyers would say if you crash. You may not be breaking the law, but you may invalidate any insurance you have.
My understanding is that the wind for your landing is considered to be whatever the last windcheck was that you got. This is similar to the RVR issue. Once you've received an RVR report which is above minima you'd better hope that they don't report another one.
The other part to my answer is this. Most (all?) Pilot Operating Handbooks state a maximum demonstrated crosswind. That's the most that the manufacturer managed to demonstrate that the aircraft can land in. If, during the certification, they didn't have any windy days then they can only give the max crosswind that they managed to demonstrate. The C152 is a prime example. It's max demonstrated crosswind is 12 knots. I (along with many others) have demonstrated that it can land in more than twice that much. But it's what the manufacturer managed to demonstrate that counts for the book.
Finally you have to ask yourself what the lawyers would say if you crash. You may not be breaking the law, but you may invalidate any insurance you have.
couple of points, definition of a gust, last time I checked, was ten knots or more from mean wind speed. (the French, for reasons best known to themselves, always seem to like to include the maximum, as in "5 kts gusting 8 kts!)
Wind passed by atc when cleared to land is usually average over last two minutes - you can always ask for the "instant" winds.
Different operators have different guidance in their operations manuals, one I am familiar adds half of the total gust to the mean wind crosswind component when deciding to assess whether within cross wind limits.
Hope this helps
Wind passed by atc when cleared to land is usually average over last two minutes - you can always ask for the "instant" winds.
Different operators have different guidance in their operations manuals, one I am familiar adds half of the total gust to the mean wind crosswind component when deciding to assess whether within cross wind limits.
Hope this helps
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To me , demonstrated x wind is a limitation.
I`m an airline pilot , not a test pilot. So I`m not allowed to push an airplane into the unknown .
In the Airbus :
For T/O they state 32 Kts(gusts included) and for LDG 40Kts (Gusts included)
Below that , there is a note which says:
"The maximum demonstrated crosswind value is not an AFM limitation : It`s the maximum crosswind experienced during the aircraft certification campaign.Airbus recommends that operators should not intencionally operate in crosswinds that exceed this value."
I think I replied your question.
I`m an airline pilot , not a test pilot. So I`m not allowed to push an airplane into the unknown .
In the Airbus :
For T/O they state 32 Kts(gusts included) and for LDG 40Kts (Gusts included)
Below that , there is a note which says:
"The maximum demonstrated crosswind value is not an AFM limitation : It`s the maximum crosswind experienced during the aircraft certification campaign.Airbus recommends that operators should not intencionally operate in crosswinds that exceed this value."
I think I replied your question.
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My 0.02 is, that crosswind is above the threshold of the limitation due to the gust. Therefore, I would wait for another shot for the approach or otherwise go elsewhere...
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margin of safety
FYI from B777 Training Manual
The crosswind guidelines shown below were derived through flight test data, engineering analysis and flight simulator evaluations. These crosswind guidelines are based on steady wind (no gust) conditions and include all engines operating and engine inoperative. Gust effects were evaluated and tend to increase pilot workload without significantly affecting the recommended guidelines.
There are numerous other points to consider but anytime the aircraft is flown near any limitation, it's best to assess what margin of safety is left for your own "personal technique".
The crosswind guidelines shown below were derived through flight test data, engineering analysis and flight simulator evaluations. These crosswind guidelines are based on steady wind (no gust) conditions and include all engines operating and engine inoperative. Gust effects were evaluated and tend to increase pilot workload without significantly affecting the recommended guidelines.
There are numerous other points to consider but anytime the aircraft is flown near any limitation, it's best to assess what margin of safety is left for your own "personal technique".
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Yes Limit
Hi, thanks for the feedback so far.
Yes it is a limit for us.
The 604 had the limit only on the reverser, when memory serves.
But acc. AFM 605 it is a hard limitation.
However, I am surprised to find no clear statement.
Sure, common sense and my will to become 100 years might lead me to avoid landing at 50kts cross, but for me it is a legal question for sim checkrides for example.
Yes it is a limit for us.
The 604 had the limit only on the reverser, when memory serves.
But acc. AFM 605 it is a hard limitation.
However, I am surprised to find no clear statement.
Sure, common sense and my will to become 100 years might lead me to avoid landing at 50kts cross, but for me it is a legal question for sim checkrides for example.
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My mob says 38kt incl gusts for the A320 suck-squirt. Quite
definitive and cuts out any doubt.
The Frogmobile is quite capable of handling up to 50kts dry
and 40kts wet and regularly done in the sim just for practice
if ever a day comes when you might have to do it to survive.
"Max-demonstrated" should be THE limitation where your job
can hang in the balance - accept a few knots above and then
accidently take out just a couple of edge lights, and suddenly
max-demonstrated becomes the deciding factor in the Safety
pilot's office in giving you the arse. Believe me its happened.
definitive and cuts out any doubt.
The Frogmobile is quite capable of handling up to 50kts dry
and 40kts wet and regularly done in the sim just for practice
if ever a day comes when you might have to do it to survive.
"Max-demonstrated" should be THE limitation where your job
can hang in the balance - accept a few knots above and then
accidently take out just a couple of edge lights, and suddenly
max-demonstrated becomes the deciding factor in the Safety
pilot's office in giving you the arse. Believe me its happened.
If it's a limitation, then it's a limitation.
... so as a pilot, all you need ask yourself is "Can I guarantee that I will land under the limitation, given the information I have?"
... and in your case there is only one answer, given the information you have: No
(Which doesn't stop you from gathering better information - i.e. ask the tower for the current measured wind.)
limit of 24 knots, and you have a wind from 90 degrees off with 20 knots gusting 30 knots.
... and in your case there is only one answer, given the information you have: No
(Which doesn't stop you from gathering better information - i.e. ask the tower for the current measured wind.)
At dispatch, under JAR-OPS/EASA-OPS gusts in METARs and TAFs may be ignored for all but ETOPS alternates when comparing with wind limitations. That implies to me that one would expect the same to be applied in flight.
I'm with Denti -- if such a limitation is published in a manual, one would expect the manual to cover the issue of what the limit applies to.
I'm with Denti -- if such a limitation is published in a manual, one would expect the manual to cover the issue of what the limit applies to.
bookworm - my company ops manual shows a chart which states that (and states that the chart comes from JAR-OPS) - however as I understand it, the chart has been removed from JAR/EU-OPS. In any case, I don't think it implies that you may ignore a limitation - you may use it for planning, and then be forced to use your emergency authority to actually land over the limitation if you don't have fuel to divert.
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Crosswind Certification - How does it affect you?
Have a look at this: http://www.nlr.nl/id~5114/lang~en.pdf
There is often confusion among pilots how to interpret the maximum
demonstrated crosswind component as given in the aircraft flight manual and in
the aircraft operating manual. A recent survey amongst 81 airline pilots of 5
operators done by the Germany accident investigation board BFU gave some
interesting facts about this problem. When the BFU gave the scenario of a
maximum demonstrated crosswind component of 33 kts. gusting 38 with a
actual wind gusting up to 40 kts., 40% of the pilots replied that landing is
permitted if gusts were not perceived as operationally relevant, 36% replied
landing is not permitted because the gust would exceed operational limits of the
aircraft, 20% said landing is permitted because gusts are irrelevant for crosswind
computations as only steady wind counted, and 4% had no idea. On the
question what is the practical meaning in normal flight operations of the term
“demonstrated crosswind” in the aircraft operating manual, 50% replied that it is
a limit, 47% replied it is guidance, and 3% did not know. (from: http://www.nlr-atsi.com/eCache/ATS/14/919.pdf )
There is often confusion among pilots how to interpret the maximum
demonstrated crosswind component as given in the aircraft flight manual and in
the aircraft operating manual. A recent survey amongst 81 airline pilots of 5
operators done by the Germany accident investigation board BFU gave some
interesting facts about this problem. When the BFU gave the scenario of a
maximum demonstrated crosswind component of 33 kts. gusting 38 with a
actual wind gusting up to 40 kts., 40% of the pilots replied that landing is
permitted if gusts were not perceived as operationally relevant, 36% replied
landing is not permitted because the gust would exceed operational limits of the
aircraft, 20% said landing is permitted because gusts are irrelevant for crosswind
computations as only steady wind counted, and 4% had no idea. On the
question what is the practical meaning in normal flight operations of the term
“demonstrated crosswind” in the aircraft operating manual, 50% replied that it is
a limit, 47% replied it is guidance, and 3% did not know. (from: http://www.nlr-atsi.com/eCache/ATS/14/919.pdf )
my company ops manual shows a chart which states that (and states that the chart comes from JAR-OPS) - however as I understand it, the chart has been removed from JAR/EU-OPS.
GM1-CAT.OP.AH.180 Selection of aerodromes - aeroplanes
APPLICATION OF AERODROME FORECASTS
A number of errors appear to have been inadvertently introduced compared to the JAR-OPS IEM.
In any case, I don't think it implies that you may ignore a limitation - you may use it for planning, and then be forced to use your emergency authority to actually land over the limitation if you don't have fuel to divert.
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Thanks
Hi all,
Thanks a lot for your suuport.
Sure, we know all, we will not land at gusting 50kts from the right!
The question is more theoretical unrelated to preparation and anything.
Scenario:
Simride approaching 8 Miles Final
Windcheck 360/20 gusting 32 (RWY 27)
Limitation:
24 kts Hard limitation (not stated as demonstrated also no gusting limitation. Just 24. Thats it.)
Question:
Dry - Legal or not?
Wet - Legal or not?
Thanks a lot for your suuport.
Sure, we know all, we will not land at gusting 50kts from the right!
The question is more theoretical unrelated to preparation and anything.
Scenario:
Simride approaching 8 Miles Final
Windcheck 360/20 gusting 32 (RWY 27)
Limitation:
24 kts Hard limitation (not stated as demonstrated also no gusting limitation. Just 24. Thats it.)
Question:
Dry - Legal or not?
Wet - Legal or not?
Simride answer - Not legal, divert. Taking the conservative, safe option can't be argued with.
Real world - it only matters if you crash, and are attempting to explain to a non-pilot, frequent passenger judge, how you left the runway in a 38 knot gust you were warned about and knew was:
Real world - it only matters if you crash, and are attempting to explain to a non-pilot, frequent passenger judge, how you left the runway in a 38 knot gust you were warned about and knew was:
- possible, and
- was greater than the certified aircraft limit.
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The C152 is a prime example. It's max demonstrated crosswind is 12 knots.
The minimum demonstration requirement is 20% over the stalling speed. If you only demonstrate the minimum, then you can't be sued for anything higher, while still allowing operations (as it's only demonstrated) up to the "pilot limit" 