Definition of term "patches" (RW condition)
 

Hi,
I'm looking for any official document where the definition of term "patches" is given (regarding RW condition).
E.g. "RW wet, patches of wet snow up to 3mm".

I believe "patches" means less than 25%, but I'm unable to find any document to support it.

Your help will be greatly appreciated!

In the US the term “patchy” can only be applied to non runway surfaces.



“New Field Condition NOTAM policy about the term “Patchy”. Based on airport operator requests, the FAA will be reintroducing the term “Patchy” to NOTAM policy with the release of the FAA Order 7930.2S, Notices to Airmen (NOTAM). The Order 7930.2 release can be expected in early 2019. “Patchy” describes contaminants that may be intermittently present on the taxiway(s) and aprons. The term:

 Can apply to taxiway(s) and aprons.
 Cannot be used to describe runway contaminants.
CertAlert No. 18-07 3 Updated 11/13/2018

 Should be used for taxiway(s) or aprons with 25 percent or less coverage of a particular contaminant, and where the depth is not reported.
 Can currently only be reported using the NOTAM free-form capabilities. NOTAM system business rules changes will eventually make the term available via the NOTAM manager dropdown menu.

The following example illustrates how an airport operator might use the term: “TWY A FICON PATCHY COMPACTED SN”. The plain language translation of this example is: Taxiway Alpha field condition is patchy compacted snow.
The FAA is adding guidance about the use of the term “Patchy” to Advisory Circulars 150/5200-28F, Notices to Airmen (NOTAMs) for Airport Operators, and 150/5200-30D, Airport Field Condition Assessments and Winter Operations Safety, and to Order 7930.2, Notices to Airmen (NOTAM).D SN”. The plain language translation of this example is: Taxiway Alpha field condition is patchy compacted snow.

https://www.faa.gov/airports/airport...-07-NOTAMS.pdf


Here’s FAA Circular Order 7930.2S:


“5−1−4.b.4. Field Conditions (FICON) Reporting. Conditions. Added language: For taxiways and aprons, do not express the condition in terms of percentage of coverage. Use the word “PATCHY” to describe a contaminant that covers 25 percent or less of the reported portion of the surface of a taxiway, apron, heliport or airport.”

https://www.faa.gov/documentLibrary/...en_(NOTAM).pdf

Thank you, CaptainMongo!
Although I do not operate in US, your answer is very helpful!