COMDTINST 16550.5
ABS protection) is disseminated to the aviation community via Notices to Airman
(NOTAMs) which are strictly controlled by the FAA. NOTAMs are issued in two
ways, via an on-line computer data base (NOTAM-Ds) by the U.S. NOTAM Office
(ATM-611 or NFDC), and in a bi-weekly published version (type-2 NOTAMs)
produced by the Air Traffic Publications Office (ATP 210). The FAA is only
interested in future or ongoing Loran-C and OMEGA unusable periods.
b.
The NOTAM Office will issue NOTAM-Ds for scheduled outages when submitted
within a time frame of 3 to 30 days prior to the event. NOTAM-D announcements of
unscheduled outages shall be submitted as they occur (as outlined in subparagraphs
6a and 6b). The fax procedure outlined here apply to the NOTAM-D announcements
(ATM-611 or NFDC) only. Either the AIG or the fax procedure may be used for
scheduled events. However, NOTAMS for unscheduled, on-going outages must be
submitted via the fax procedure.
c.
In order to submit Type-2 NOTAMs for publication, the Air Traffic Publications
Office requires at least 17 days notice prior to the event. These NOTAMs will
continue to be handled via the AIG method.
d.
In order to certify Loran-C for aviation use in non-precision approaches to CONUS
airports, the Coast Guard is developing the Automatic blink System (ABS). When
fully implemented, this system will provide users with an early warning of possible
Loran signal inaccuracies by automatically blinking the signal within 10 seconds of
detection of a problem. When this protection is not available, the Loran signal must
be blinked until a NOTAM (NOTAM-D, ATM-611 or NFDC) can be issued to warn
pilots not to use that station or chain. The introduction of ABS is the primary driving
force to this instruction.
e.
The fax machine will now be used to submit NOTAM-D (ATM-611 or NFDC)
requests for unscheduled, continuing outages to the FAA vice the traditional
message procedure. The FAA's NOTAM Office maintains a 24-hour watch adjacent
to their fax machine. The traditional message AIG procedure is no longer acceptable
for on-going outages due to the potential of unnecessary blink periods caused by an
ABS failure. During periods of communications minimizes, this could exceed twelve
hours.
5.
Responsibilities.
a.
Loran-C Regional Managers have the responsibility to issue and cancel all Loran-C
NOTAMs for scheduled outages of a duration of greater than 2 hours and will keep
track
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