If you customarily fly in warm, sunny climes you may not be familiar with some of the winter-weather contractions found in NOTAMs.
Last night the Seattle area experienced moderate snow followed by steady rain. Today’s NOTAMs for KPAE included these entries:
RWY 16R VER MU 43/45/39. 12 JAN 15:10 2011 UNTIL UFN. CREATED: 12 JAN 15:31 2011 TWY C,W,G,F 2 IN SN. 12 JAN 14:51 2011 UNTIL UFN. CREATED: 12 JAN 14:52 2011 RWY 16R/34L THN PTCHY SLR. 12 JAN 14:52 2011 UNTIL UFN. CREATED: 12 JAN 14:532011
“THN PTCHY SLR” is easy enough: thin patchy slush on runway 16R/34L. Taxiways C,W,G and F have two inches of snow. The MU entry is slightly more involved. “Mu” is used to report the runway’s surface friction quantities, or more simply, how slippery the runway is.
Section 4.3.9 in the FAA AIM explains this with more depth: a Mu of 0 is the lowest friction value, and 100 is the highest. Mu of 40 or lower indicates a level where braking and directional control deteriorate.
The first entry in “VER MU 43/45/39” denotes the type of recording equipment in use. You can reference page 5 of the FAA’s Winter NOTAM Reporting PDF to determine that VER stands for Vericom VC3000:
BOW Bowmonk Decelerometer (Bowmonk Sales) BRD Brakementer-Dynometer ERD Electronic Recording Decelerometer (Bowmonk) GRT Griptester (Findlay, Irvine, LTD) MUM Mark 4 Mu Meter (Bison Instruments, Inc.) RFT Runway friction tester (K.J. LAW Engineers) SFH Surface friction tester (high pressure tire) (SAAB, Airport Surface Friction Tester AB) SFL Surface friction tester (low pressure tire) (SAAB, Airport Surface Friction Tester AB) SKH Skiddometer (high pressure tire)(AEC, Airport Equipment Co.) SKL Skiddometer (low pressure tire) (AEC, Airport Equipment Co.) AP Tapley Decelerometer (Tapley Sales) VER Vericom (VC3000)
The three separate numbers following the MU denote the friction values for the three thirds of the runway, or as the AIM says, “for each one-third zone…in the direction of takeoff and landing on the runway.” Thus 16R’s first third’s Mu is 43, the middle third’s Mu is 45, and the last third is 39.
The NOTAM information above would, in summary, indicate a runway with a fair amount of contamination having relatively significant impact to aircraft controllability and braking.
In addition to the Winter NOTAM PDF above, I recommend you download this PDF of Approved NOTAM Contractions for the days when you encounter unfamiliar contractions.