7754 Vol 2 Flyleaf - ICAO Public Maps

III-A1
Attachment A
GUIDANCE ON THE MEASURING AND
REPORTING OF RUNWAY STATE INFORMATION
(Paragraph 17, Part III — AOP refers)
GENERAL PROVISIONS
Issue and validity of SNOWTAM
1. The validity of SNOWTAM should normally be
limited to six hours and should, in no case, exceed a
maximum validity of 24 hours.
Notification of closure of an aerodrome due to
snow and/or ice conditions and its re-opening
2. Supplementary to the issue of the appropriate
SNOWTAM, the temporary closure of an aerodrome in
order to permit removal of snow and/or ice and its
subsequent reopening should be made the subject of a
separate NOTAM Class I, issued with the priority prefix
―DD‖.
Promulgation of runway state information for
aerodromes that are closed at night
3. Information on the runway state at aerodromes that
are used regularly by scheduled air services and that are
closed at night or do not have night operations, should be
promulgated as follows:
a) whenever snowfall or freezing conditions are forecast or
have been observed, the aerodrome meteorological
office concerned should advise the airport operator in
sufficient time so as to permit the promulgation of
appropriate information on the runway state at least two
hours before the aerodrome reopens;
b) when such conditions exist, appropriate information on
the runway state should be promulgated two hours
before the aerodrome is reopened for operations; and
c) information issued in accordance with b) above should
be updated immediately, if this is required in view of
rapidly changing conditions.
RUNWAY BRAKING ACTION
Measuring of braking action
4. Measurements of braking action on runways
affected by dry snow or ice should be made by the use of a
continuous measuring device (e.g. Skiddometer or
Mu-meter). Where this is not possible, a decelerometer (e.g.
Tapley-meter) may be used. In order to achieve compatible
results between the two types of equipment, the practice for
tests outlined in Annex 14, Volume I, Attachment A,
Section 6 should be employed.
5. When measuring devices are used for the
assessment of runway braking action, the results should be
reported in accordance with the following:
Measured or calculated
coefficient of friction
Ice and dry snow
Estimated braking action
0.40 and above GOOD 5
0.39 — 0.36 MEDIUM/GOOD 4
0.35 — 0.30 MEDIUM 3
0.29 — 0.26 MEDIUM/POOR 2
0.25 and below POOR 1
Code
unreliable UNRELIABLE 9