SNOWTAM.
How to interpret a SNOWTAM.
SNOWTAM and MOTNE RWY reports are only provided for winter conditions
(snow, ice etc) but not for other hazardous RWY conditions e.g RWY
slippery when wet or, wet combined with dust.
Observations and measurements are made at routine intervals but only
when RWY are contaminated and/or when there are significant changes.
There are certain definitions used in SNOWTAM and MOTNE.
- DAMP
- The surface shows a change of color due to moisture.
- WET
- The surface is soaked but there is no standing water.
- WATER PATCHES
- Significant patches of standing water are visible.
- STANDING WATER
- Standing water of significant depth and area which affects the braking
action (aquaplaning).
- FLOODED
- Extensive standing water is visible.
- DRY SNOW
- Snow which can be blown if loose. If compacted by hand, will fall apart
again upon release.
- WET SNOW
- Snow which, if compacted by hand will stick together and tend to form
a snowball.
- SLUSH
- Water saturated snow which with a heel-and-toe slap-down motion against
the ground will be displaced with a splatter.
- COMPACTED SNOW
- Snow which has been compressed into a solid mass that resists further
compression and will hold together or break up into chunks if picked up.
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SNOWTAM example.
A)LSZH B)11070620 C)10 D)2200 E)40L F)4/5/4
G)20/10/10 H)30/35/30MUM J)30/5L K)YES L L)TOTAL M)0900
P)YES 12 S)11070920 T)FIRST 300M RWY 10 COVERED BY 50
MM SNOW, RWY CONTAMINATION 100%
- A)LSZH
- AERODROME LOCATION INDICATOR
- B)11070620
- DATE/TIME OF OBSERVATION (in UTC)
- C)10
- RUNWAY DESIGNATORS
- D)2200
- CLEARED RUNWAY LENGTH, if less than published length (m).
- E)40L
- CLEARED RUNWAY WIDTH, if less that published. (m; if offset left or right
of center line add "L" or "R").
- F)4/5/4
- DEPOSITS OVER TOTAL RUNWAY LENGTH (Observed on each third of the runway
starting from threshold having the lower runway designation number).
NIL - CLEAR AND DRY
1 - DAMP
2 - WET
3 - RIME OR FROST
4 - DRY SNOW
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5 - WET SNOW
6 - SLUSH
7 - ICE
8 - COMPACTED SNOW
9 - FROZEN RUTS OR RIDGES
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- G)20/10/20
- MEAN DEPTH (mm) FOR EACH THIRD OF TOTAL RUNWAY LENGTH.
- H)30/35/30
- FRICTION MEASUREMENT ON EACH THIRD OF RUNWAY AND FRICTION MEASURING DEVICE.
MEASURED or CALCULATED COEFFICENT
0.40 and above
0.39 - 0.36
0.35 - 0.30
0.29 - 0.26
0.25 and below
9
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ESTIMATED SURFACE FRICTION
5 - GOOD
4 - MEDIUM/GOOD
3 - MEDIUM
2 - MEDIUM/POOR
1 - POOR
9 - Unreliable
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TYPE OF MEASURING EQUIPEMENT USED
BRD=Brakemeter-Dynometer
GRT=Grip Tester
MUM=Mu-meter
RFT=RWY friction tester
SFH=Surface Friction tester
(high pressure tire)
SFL=Surface Friction Tester
SKH=Skiddometer
(high pressure tire)
SKL=Skiddometer
(low pressure tire)
TAP=Tapley meter
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- J)30/5L
- CRITICAL SNOWBANKS. If present, insert height (cm) / distance from the edge
of runway (m) followed by L or R or LR if applicable.
- K) YES L
- RUNWAY LIGHTS (If obscured insert YES followed by L or R or both LR if applicable.
- L) TOTAL
- FURTHER CLEARANCE(If planned insert length (m) / width(m) to be cleared or
if full dimensions insert TOTAL.
- M)0900
- FURTHER CLEARANCE EXPECTED TO BE COMPLETED BY...(UTC).
- N)...
- TAXIWAY (if no appropriate taxiway is available, insert NO).
- P)YES 12
- TAXIWAY SNOWBANKS (If more than 60 cm, insert "YES" followed by distance apart, m)
- S) 11070920
- NEXT PLANNED OBSERVATION/MEASUREMENT IS FOR (month/day/hour UTC).
- T) First 300M RWY 10 covered by 50 mm
- PLAIN LANGUAGE REMARKS (Including contaminant coverage and other significant
information like sanding or deicing).
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