Sigmet, Basic service weather products – BendixKing KMD 540 - Addendum System KMD 850 User Manual
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Revision 6 Feb/2009
KMD 550/850 FIS Addendum
3.
Date and time issued
4.
Report designation and reason for issuance
5.
Validity period
6.
Area of coverage
7.
Weather phenomenon details.
These reports are displayed in an encoded textual format.
NOTE: AIRMETs may be issued up to 15 minutes prior to the start of the
validity period. The system will display the data age as zero until the start
of the validity period. AIRMETs older than 360 minutes are discarded.
Amended, updated or corrected AIRMETs generated withing the
issuance period are provided as soon as they are available, and the pre-
vious outdated AIRMET is no longer transmitted.
When an AIRMET is cancelled, neither the original report nor the cance-
lation message can be displayed.
See Appendix A for instructions on decoding textual AIRMETs.
SIGMET
A SIGMET (Significant Meteorological Information) is an advisory of non-
convective weather that is potentially hazardous to all aircraft. SIGMETs
address details regarding severe icing not associated with thunder-
storms, severe or extreme turbulence not associated with thunderstorms,
dust or sand storms lowering visibility to less than 3 miles, volcanic ash.
SIGMETs are considered widespread because they must either be
affecting or forecast to affect an area at least 3,000 square miles.
However, during the forecast period, the actual affected area may be
much smaller. SIGMETs are issued as needed and the maximum fore-
cast period is 4 hours, except for 6 hours for conditions associated with
hurricanes. A SIGMET will contain elements in the following order:
1.
Forecast Area
2.
Report Type
3.
Date and time issued
4.
Report designation and reason for issuance
5.
Validity period
6.
Area of coverage
7.
Location of weather phenomenon
8.
Weather phenomenon details.
These reports are displayed in an encoded textual format.
NOTE: SIGMETs older than the forecast period are discarded.
Amended, updated or corrected SIGMETs generated withing the
issuance period are provided as soon as they are available, and the pre-
vious outdated SIGMET is no longer transmitted.
Basic Service Weather Products