Contaminated runways Norway
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Contaminated runways Norway
A few years back, Norway started to sometimes to give runway contamination in quite a special way :
"Runway covered with XX % XXXX (contamination), ON ICE"
e.g. "Runway covered with > 50 % slush, 3mm, on ice"
The special thing is the "on ice"
Normally when you saw the runway, there were no ice to see, maybe a few % on the edges.
This is probably a "cover my ass" procedure from AVIANOR, but it present quite a problem for operators, as you are normally not allowed to operate on ice.
How do you deal with it ?
"Runway covered with XX % XXXX (contamination), ON ICE"
e.g. "Runway covered with > 50 % slush, 3mm, on ice"
The special thing is the "on ice"
Normally when you saw the runway, there were no ice to see, maybe a few % on the edges.
This is probably a "cover my ass" procedure from AVIANOR, but it present quite a problem for operators, as you are normally not allowed to operate on ice.
How do you deal with it ?
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I have never heard about this in Norway. Are you sure this is standard?
My experience is that the ATIS tells how many percent of the runway is covered with contamination, type of contamination and surface friction in the scale poor, med-poor, medium, med-good, and good. SNOWTAM reports are also available with detailed information.
Why are you not allowed to operate on ICE if the surface friction is adequate?
My experience is that the ATIS tells how many percent of the runway is covered with contamination, type of contamination and surface friction in the scale poor, med-poor, medium, med-good, and good. SNOWTAM reports are also available with detailed information.
Why are you not allowed to operate on ICE if the surface friction is adequate?
Wet Ice
Surface friction measurement is a very inexact science, we don't use it at all for performance calculations. Only the type of contaminant is considered relevant and that is what we use. A report of slush on top of ice is, in effect, WET ICE. Airbus describes this:
"Wet ice: when the ice on a runway melts, or there are loose/fluid contaminants on top of the ice, the ice is referred to as "wet ice". When there is wet ice on a runway, braking and directional control are difficult or not possible, because the runway surface is very slippery"
Therefore, don't operate on runways covered with such a contaminant as the actual braking action will probably be NIL !
On the other hand, ICE which is cold and dry is acceptable, provided performance is calculated using POOR as the related performance level.
"Wet ice: when the ice on a runway melts, or there are loose/fluid contaminants on top of the ice, the ice is referred to as "wet ice". When there is wet ice on a runway, braking and directional control are difficult or not possible, because the runway surface is very slippery"
Therefore, don't operate on runways covered with such a contaminant as the actual braking action will probably be NIL !
On the other hand, ICE which is cold and dry is acceptable, provided performance is calculated using POOR as the related performance level.
Last edited by Nightstop; 15th Dec 2015 at 10:56. Reason: Dry ice added
From Airbus regarding performance - "An accumulation of layers of different contaminants. Accident and incident data for
water on top of compacted snow, water on top of ice (or wet ice), or dry/wet snow on top of ice has shown unacceptable impact on aircraft performance and operations cannot be supported, even via adoption of the most conservative contaminant, i.e. ice."
An Airbus on ice
water on top of compacted snow, water on top of ice (or wet ice), or dry/wet snow on top of ice has shown unacceptable impact on aircraft performance and operations cannot be supported, even via adoption of the most conservative contaminant, i.e. ice."
An Airbus on ice
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I had the "...on ice" the week before last. Yet the Braking Action was reported initially as Med-Med-Good. But our performance doesn't use Braking Action (that would be too simple, wouldn't it) only a contaminant. I'm convinced if we used Braking Action to determine our performance, airports would report contaminants that we could couldn't use; anything to make sure they can never be held liable for us using their runway. After the runway had been re-swept the braking action improved to Good x3 but with the "...on ice" remaining. So we used "Ice" to do our calculations and departed. We used so little runway that we would have had to use power to get to the upwind end.
Not perfect and yes I'm vulnerable.
PM
Not perfect and yes I'm vulnerable.
PM
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the rumor says, that the lawyers of AVINOR recommends that the Norwegian airports use the term : "xxxxx contamination ON ICE", when there is the slightest presence of ice.
This is to be sure no company can come after AVINOR if an accident happens.
As operators in Scandinavia knows, there have been quite a few incidents over the years in Norway, where the reports from the airports about contamination/B.A. have been incorrect (actual B.A. most worse than reported)
Problem is operators of Airbus are not allowed to operate on ice covered runways (> 25 %)
so this is a problem that has to be solved
This is to be sure no company can come after AVINOR if an accident happens.
As operators in Scandinavia knows, there have been quite a few incidents over the years in Norway, where the reports from the airports about contamination/B.A. have been incorrect (actual B.A. most worse than reported)
Problem is operators of Airbus are not allowed to operate on ice covered runways (> 25 %)
so this is a problem that has to be solved
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Heard the same thing in Torp yesterday, "wet, on ice" braking action good. Sounds like a bit of a contradiction.
Gardermoen had "Slush on ice".
We do not use the BA but the TALPA matrix, so anything on ice is basically poor and no-go, especially if they start reporting wet (on) ice (even with a good BA)
Gardermoen had "Slush on ice".
We do not use the BA but the TALPA matrix, so anything on ice is basically poor and no-go, especially if they start reporting wet (on) ice (even with a good BA)
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They are reporting correctly, though it may seem a bit confusing of you are in addition not used to driving a car during the winter no slippery conditions. At the other end of the scale is "summer conditions", meaning there is bare and dry asphalt even though the calendar is clearly showing a winter month. Contaminated runways are cleared, swept and sanded (often warm sand which melts in whatever ice/snow is remaining), and breaking action is measured by a grip tester, or by estimate where no grip tester exists. So anything other than "summer conditions" during the winter will usually have the "... on ice" at the end. Use whatever breaking action the give you for your performance calculations
They're telling you what is on the runway and how slippery it may or may not be.
They're telling you what is on the runway and how slippery it may or may not be.
They used to spread hot sand on packed snow and ice and we'd land on it quite happily in quadropuffs with no reverse - braking action was fine. (Dagali, Norway) Mind you, it was a bitch figuring out where the runway stopped and the bundhu started or vv. Identifying the limits of the landing surface was by far the hardest bit. I never quite figured how all this worked as far as the Ops manual was concerned but then BWA was a bit of a world unto itself and it wasn't politic for the likes of me to question their SkyGods, of which there were many. It certainly didn't seem hazardous though.
