instrumentation /.nstrυmen
te..(.)n/ noun a set of specialised instruments on an aircraft . Instrumen-tation in some basic light aircraft is restricted to a few instruments only. . Some modern light aircraft have very sophisticated instrumentation.

instrument error /.nstrυm.nt
er./ noun the difference between indi-cated instrument value and true value

instrument flight rules
/.nstrυm.nt fla.t rulz/ plural noun
regulations which must be followed when weather conditions do not meet the minima for visual flight . The flight from Manchester to Prestwick was con-ducted under instrument flight rules.
Abbreviation IFR instrument flying /.nstrυm.nt
fla.../ noun flying using no references other than the flight instruments . Some conditions require instrument flying. . When in cloud, instrument flying is required. Abbreviation IF
instrument landing /.nstrυm.nt lnd../ noun the landing of an aircraft when a pilot is relying on information obtained from instruments rather than from what can be seen outside the air-craft

instrument landing system
/.nstrυm.nt lnd.. s.st.m/ noun
aids for an instrument landing approach to an airfield, consisting of a localiser, glide slope, marker beacons and approach lights . The instrument land-ing system provides both horizontal and vertical guidance to aircraft approach-ing a runway. Abbreviation ILS
COMMENT: The ILS is the most used precision approach system in the world.
instrument meteorological con-ditions /.nstrυm.nt miti.r. l.d.k(.)l k.nd..(.)nz/ plural noun meteorological conditions of visibility and distance from cloud ceiling which are less than those for visual meteoro-logical conditions . The basic licence does not permit the pilot to fly in instru-ment meteorological conditions. Abbre-viation IMC

instrument rating /.nstrυm.nt
re.t../ noun an additional qualifica-tion added to a licence, such as PPL, allowing a pilot to fly in instrument meteorological conditions . He gained his instrument rating in 1992. Abbrevi-ation I/R
COMMENT: An instrument rating is required for operating in clouds or when the ceiling and visibility are less than those required for flight under visual flight rules (VFR).
insufficient /.ns.f..(.)nt/ adjec-tive not enough . Insufficient height resulted in the pilot landing short of the runway.
insulate /.nsjυle.t/ verb 1. to prevent the passing of heat, cold or sound into or out of an area 2. to prevent the pass-ing of electricity to where it is not required, especially by using a non-con-ducting material . Bus bars are insu-lated from the main structure and are normally provided with some form of protective covering.
insulating /.nsjule.t../ adjective
preventing the unwanted passage of heat, cold, sound or electricity
insulating tape /.nsjυle.t.. te.p/
noun special adhesive tape which is used to insulate electrical wires . Insu-lating tape was used to prevent the elec-trical wires from touching.