Some winter ops questions...

[Beirut pilot]

1. RXX/410164...If i understood this right it means that this runway is contaminated with dry snow and is covered at 10% or less. It has also a depth of 1mm and the braking action is good.

So my question is if this runway is considered contaminated,wet or dry in your takeoff performance calculations? I mean doesn't a runway have to be 25% covered to be classified as contaminated? Or is it ''just'' wet?
Is it the same if the runway is ''icy'' at 10%?

2.If a runway is considered wet (or maybe contaminated?) and you have at this wonderful little airport a clearway of 500m, why do you get a larger penalty than if no clearway would have been available? Is it because of the longer ''span'' between Vr and V2? And if so is there any trick to get around it? Like reduced clearway? Or is that just a big no no? If so why?

[Sir George Cayley]

I'd post a 1 hour delay, grab a coffee and try again later.

[Cough]

Question 1 - From 'ere (EASA land!) (http://www.easa.europa.eu/agency-measures/docs/opinions/2011/04/Annexes%20to%20Regulation.pdf)

‘Contaminated runway’ means a runway of which more than 25% of the runway
surface area within the required length and width being used is covered by the
following:
(a) surface water more than 3 mm (0.125 in) deep, or by slush, or loose snow,
equivalent to more than 3 mm (0.125 in) of water;
(b) snow which has been compressed into a solid mass which resists further
compression and will hold together or break into lumps if picked up
(compacted snow); or
(c) ice, including wet ice.

I'll let you decide if you apply wet/dry perf.

Question 2. pass!

[RTN11]

ATC seem to have a different definition of what is contaminated, as I've often been passed "the runway is contaminated with 2mm of slush" which from our performance point of view is not contaminated, just wet, from theirs any contaminant makes it contaminated, and they just pass what they see.

So you get passed that it is 10% contaminated, from your performance point of view it isn't contaminated at all, so use wet performance figures.

Sir George Cayley has the right idea though, in reality any contaminant will likely have the ground guys out deicing the runway, grab a coffee, wait an hour, and see what it looks like then. :ok: