A braking action on an Atis can relate to a runway surface condition as well as the environmental situation .
So if the Tarmac or concrete surface has deteriorated below a nominal value of friction, airports are obliged to report a braking action even in the height of summer.
Braking action values are based on the equipment used at the airport. Outside of Canada which use CRFI nationwide the value will vary based on whether it is skiddometer Saab mu meter or whatever device is used.
The last 2 digits of a MOTNE can either be a friction value or can be a braking action.
I'll correct myself and say that the MOTNE is independent of the Notam system, apologies for the confusion. But the premise that a MOTNE may not update with the METAR time is correct, or alternatively it can mean that there is no significant change to the report
Last edited by safewing; 7th Jan 2013 at 15:00.