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NIMS, Nims
important where creep-resistance essential; Inconel,
Hastelloy, Udimet and Waspalloys related.
NIMS, Nims National airspace system Infrastructure
Management System (FAA).
90-minute rule Certification requirement that twinengined
passenger aircraft may fly transoceanic sectors
provided they are never more than 90 minutes from an
emergency alternate.
The 99s US women in aviation educational charity
[sometimes spelt out].
NINST Non-instrument [runway].
niobium Nb, shiny grey metal, density 8.6, MPt 2,468°C.
NIOSH National Institute for Occupational Safety and
Health (US).
NIP Network interface processor.
nip 1 Local compression between adjacent components,
esp. that used to secure a third part, eg compressor rotor
between discs.
2 Local compression caused by deflection under operating
conditions, eg axial movement at periphery of
conical compressor or turbine disc.
NIPC National Infrastructure Protection Center (US).
NIPP National Infrastructure Protection Plan
[November 2005–] (US).
Niprnet Non-classified information protocol router
network (DoD).
NIR 1 Near infra-red; S adds spectrometer.
2 Network interface router; V adds VHF data-link.
NIS 1 NATO identification system.
2 Nose-in stand (airport ramp).
3 Not in stock.
4 Not in service.
Nisac National Infrastructure Simulation and Analysis
Center (LASL/Sandia, a response to 9-11).
NISC National IFF/SSR Committee (CAA).
Nisil Ni/Si.
NISR Non-traditional intelligence surveillance and
reconnaissance.
NIST National Institute of Standards and Technology
(US, previously NBS).
nit Name, not normally used, of SI unit of luminance,
cd/m 2 .
NITE Night imaging and threat evaluation.
Nitenol Alloys of Ni and Ti, variable properties.
Nite-Op Night-imaging through electro-optics.
NITEworks Pronounced nightworks, network, integration,
test and experimentation works (UK, MoD and
industry July 2003–).
NITF National imagery transmission format.
Nitralloy British steels for nitrided parts with small
amounts of Cr, Al, Mn, C, Si and possibly Ni and Mo.
nitrate dope Aircraft fabric dope comprising cellulose
fibres dissolved in nitric acid, plus pigment, thinner, etc.
nitriding Surface hardening of steels by prolonged
heating in nitrogen-rich atmosphere.
nitrogen Generally unreactive gas forming 78.03% by
mass of sea-level air, symbol N 2 , BPt –195.8°C, density
1.25 gl –1 , 0.07807 lb/ft 3 ; dry gas important as inert purging
medium, liquid LN 2 used as cryogenic heat-transfer fluid.
nitrogen desaturation Human condition caused by
nitrogen deficiency.
nitrogen narcosis Human condition caused by apparent
reaction between tissue fats and nitrogen under pressure.
nitrogen tetroxide N 2 O 4 , most common storable liquid
NLR
oxidant, often called NTO, BPt 21°C, Isp 285 with
UDMH, 290 with hydrazine.
nitroguanidine Major constituent of many gun propellants,
commercial name Picrite.
Nitrojet Versatile supersonic jet of LN 2 used for cutting
and surface treatment.
nitromethane CH 3 NO 2 , oily liquid, monopropellant.
nitrous oxide N 2 O ‘laughing gas’, used as source of
oxygen in power-boosting piston engines in WW2.
NIU 1 Nitrogen inerting unit.
2 Network, or navigation, interface unit.
NIVO, Nivo Dark green night-bomber paint, later
RDM2 (RAF).
NIVR Netherlands Institute for Aerospace Development.
NIW Night and in-weather.
NJ Noise jamming.
NJE Nominal jet edge.
NJG Nachtjagdgeschwader, night-fighter group [US =
wing] (G, WW2).
NJSK Private Pilots’ Association (J).
NKAP State commissariat for aviation industry
(USSR).
NKF Non-kinetic fires.
NKK Nihon Koku Kyokai [Aeronautical Association;
main office, Tokyo 105–0004] (J).
NKG Nihon Kakai Gakkai [Society of Mechanical
Engineers; office, Tokyo] (J).
NKGK Nihon Koku Gijutsu Kyokai [Society of
Aeronautical Engineers; office Tokyo (J).
NKO State commissariat for defence (USSR).
NKRR Nihon Kikyu Remmei [Balloon Federation;
office Tokyo] (J).
NKSK Aero Engineers’ Association (J).
NKTP State Commissariat for Defence (USSR, R).
NKUGK Society of Aeronautical and Space Sciences
(J).
NKVD State commissariat for internal affairs (now
KGB).
N/kW Newtons per kilowatt, fundamental performance
measure of Hall-effect thrusters.
NL 1 Natural language.
2 Normenstelle Luftfahrt (G).
N L 1 LP rpm engine speed [N 1 preferred].
2 Normal load factor.
NLA 1 New large aeroplane study group.
2 Noise-level analyser.
NLAW Next-generation light anti-armour weapon.
NLB Nose loader, or loading, bridge; see bridge.
NLC Noctilucent cloud.
NLCM Non-lethal countermeasures.
NLES Navigation land Earth satellite.
NLF 1 Natural laminar flow.
2 Normal load factor.
NLG 1 Nose landing gear.
2 Noise Liaison Group (UK).
3 Non-linear gearing.
NLL No load lubrication.
NLM Network-loadable module.
NLO No local, or live, operator, also called nulls.
NLOS Non-line of sight; CA adds combined arms.
NLP Network layer protocol.
NLR Nationaal Lucht-en Ruimtevaartlaboratorium
[Amsterdam NL-1059] (Netherlands).
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