JP 3-50 National Search and Rescue Manual Vol I - US Navy

Inadvertent Alarm Rate: Ratio of inadvertent alarms to beacon alarms.
INCERFA: ICAO equivalent of the Uncertainty Phase.
Incident Command System (ICS): An on-scene Management-By-Objectives
system for any type of incident.
Individual Drift Error (de): Individual Drift multiplied by Confidence
Factor.
Information Request (INREQ): A message request for information about an
unreported or overdue aircraft in United States domestic airspace.
Corresponds to the declaration of the Uncertainty phase.
Initial Action Stage: A period during which preliminary action is taken
to alert SAR facilities and obtain amplifying information.
Initial Position Error (X): The assumed error of the initially reported
position of a SAR incident.
International Maritime Satellite Organization (INMARSAT): A system of
telephone direct-voice communications via geostationary satellites.
Instrument Flight Rules (IFR): Rules governing the procedures for
conducting instrument flight. Also a term used by pilots and
controllers to indicate type of flight plan.
Instrument Meteorological Conditions (TMC): Meteorological conditions
expressed in terms of visibility, distance from cloud, and ceiling less
than the minima specified for visual meteorological conditions.
Interagency Committee on Search and Rescue (ICSAR): Established to
oversee the National Search and Rescue Plan and to act as a coordinating
forum for national SAR matters.
Interferer: Non-beacon radio signals on beacon frequencies.
Knot (kt): A unit of speed equal to one nautical mile per hour.
Last Known Position (LKP): Last witnessed, reported, or computed DR
position of a distressed craft.
Leeway (LW): The movement of a search object through water caused by
winds blowing against exposed surfaces.
Local Base SAR Officer: An officer, appointed by the commanding officer
of an operational military base, to coordinate the use of local
resources with the regional RCC.
Local User Terminal (LUT): Ground station receiving, processing and
relaying data from COSPAS-SARSAT satellites.
Location: Exact geographical position of a beacon or other search
object.