The Cambridge Aerospace Dictionary Episode 7 pptx

nose ribs Ribs along leading edge extending chordwise only as far as front spar. nose slice Maximum-rate yaw induced by rudder. nose slots Apertures in low-pressure region of high velocity around nose for discharge of fluid flow, eg cooling air. nose tow Standard US Navy method of catapult link for accelerated carrier takeoff by pulling on nose leg. nose up To rotate in pitch from level flight to climb. nosewheel Wheel(s) of nose gear. no-show Airline passenger who has booked ticket but fails to check in for flight. Nosig No significant meteorological change (ICAO). no step Stencilled warning on aircraft: do not put weight on this area. NOT Naczelna Organizacja Techniczna (Polish federa- tion of engineering associations). Notal Not to all. Notam, NOTAM Notice to Airmen, identified as notice or as Airmen Advisory, disseminated by all means to give information on establishment, conditon or change in any aeronautical facility, service, procedure or hazard; suffix D distant [wide dissemination], L local (ICAO). Notam code Standard code for transmitting Notams; eg QAUED 3 MC 5813 142359 is interpreted as ‘Met com operating frequency of 3 MHz will be changed to 5,813 kHz on 14th of this month at 23.59’. Notar No tail rotor, torque reaction supplied by offset thrust from air blown through slit in tail boom (Hughes, then McDonnell Douglas, now Boeing). notch Essentially chordwise or streamwise sawcut or groove over nose of aerofoil. notch aerial Formed by cutout in skin of vehicle, leaving aperture matched to wavelength (usually in HF com. band) and covered with dielectric skin to original profile. notched cone nozzle Promising primary nozzle in ejector-lift system in which primary flow is discharged through row(s) of fishtail (lozenge-section) nozzles gener- ating plumes orthogonal to long axis of duct. notched elevators Cut away at trailing edge for rudder movement. notch effect Shortcoming of early (1960s) all-flying tailplanes or slab tails in which demands tended to be in noticeable increments [pilot often reverted to flying on trimmer]. notch flap Leading-edge flap extended from fuselage. notifiable accident One which cannot legally go un- reported, where any person suffers injury, third-party property is damaged or public are in any way put at risk; variable rules governing scale of damage to aircraft. no-transgression zone Airspace where aircraft under positive electronic IFR control must not penetrate, esp. region 900+ m/2,000+ ft wide between aircraft making ILS approaches on to parallel runways. NOTS Naval Ordnance Test Station (USN, China Lake, Inyokern etc, now NWC). Notus Notice to users (Arinc). Nova Networked open versatile architecture. NOV-AB Non-persistent Toxic-B gas bomb (USSR). Novcam Non-volatile charge-addressed memory. Novoview Range of CGI(2) visual systems, some textured (Rediffusion). Novram Non-volatile RAM. Nowcast Report on current weather. no-wind position Geographical position aircraft would have occupied had wind velocity been zero. NOx, NOX Nitrogen/oxygen breathing mixture (normally means supplied in absence of atmosphere). NO x Shorthand for all oxides of nitrogen resulting from combustion of fuel in air. noy, Noy Subjective measure of noisiness in bandwidths of one-third octave (see noise). NOZ No operating zone. nozpos Nozzle position[s], ie angle. nozzle 1 In jet-propulsion or reaction-jet control, aper- ture through which fluid escapes from system to atmosphere and in which as much energy as possible is converted to kinetic energy (see choked, con/di). 2 Wind-tunnel section immediately upstream of working section. 3 Primary aperture through which fuel is injected into gas-turbine engine combustion chamber [US usage]. 4 Section of fluid flow duct upstream of axial turbine, in which flow is controlled to enter turbine at favourable direction, pressure and velocity. Form depends on whether turbine is impulse/reaction or pure impulse. 5 Incorrectly, nozzle guide vane. nozzle blade See nozzle guide vane. nozzle block See nozzle (2). nozzle box Assembly of nozzle guide vanes (all, or a group filling portion of periphery) and surrounding walls of gas duct. nozzle bucket See nozzle guide vane. nozzle contraction ratio Ratio of flow cross-section area at inlet or start of nozzle (esp. con/di or rocket) to area at throat. nozzle diaphragm Nozzle (4) as complete assembly. nozzle efficiency Usually ratio of actual change in kinetic energy across nozzle to ideal value for given inlet conditions. nozzle exit area Area of cross-section of flow at exit. nozzle expansion ratio In supersonic nozzle, ratio of exit area to throat area. nozzle guide vane Radial aerofoils upstream of axial gas turbine, convergent passages between which form nozzle (4) through which gas is directed on to turbine rotor blades. Also called turbine stator. nozzle insert Small blocking body fixed inside nozzle (1) to trim exit area; colloq. = mice. nozzle ring Complete 360° assembly of nozzle guide vanes. nozzle throat Region of con/di nozzle having smallest cross-section area. nozzle thrust coefficient Usually defined as actual achieved thrust divided by product of chamber pressure and throat area (rocket). NP 1 Noise-preferential. 2 North Pacific region (ICAO). N p 1 Number of passengers. 2 Speed (rpm) of power turbine or, confusingly, propeller. np – Yawing moment coefficient due to rolling. NPA 1 Notice of proposed amendment (FAA, JARs). 2 National Packaging Authority (UK). 3 National Pilots’ Association [trade union] (US). 4 Non-precision approach. NPB 1 Nuclear-powered (or propelled) bomber. 2 Nadge Policy Board. nose ribs NPB 411 NPD Need and planning documents. NPDU Network protocol data unit. NPE Navy preliminary evaluation (USN). NPG 1 No performance group type aircraft (CAA). 2 Nuclear planning group. 3 Non-unit personnel generator. NPI Non-precision instrument. NPIAS National Plan of Integrated Airport Systems (US). NPL National Physical Laboratory (UK, 1899–). NPLOs NATO production and logistics organizations. NPL tunnel A closed-jet tunnel, original * = return flow, standard * = non-return flow. NPO Scientific production union (USSR, R). NPOESS National, later (2002) changed to New, polar- orbiting operational environmental satellite system (NASA, NOAA, USAF). NPP 1 Research and production enterprise (R). 2 NPOESS preparatory project. NPPL National Private Pilot’s Licence [proposed, VFR only] (UK). NPR 1 No power recovery. 2 Nozzle pressure ratio. 3 Nuclear posture review (US). 4 Noise preferential route. NPRM Notice of proposed rulemaking (FAA). NPRS Non-persistent. NPS 1 Non-prior service. 2 Naval Post-graduate School (USN). 3 Nuclear profiled sortie. NPT Non-proliferation treaty, 1 July 1968. NPTR 1 National Parachute Test Range. 2 No procedure turn required. NPU Navigation processor unit. NQA National Quality Assurance [certification authority] (UK). NQIS Navigation-quality inertial sensor. NQR Nuclear quadrupole resonance. NR, Nr 1 Helicopter main-rotor rpm. 2 Network router. nr – Yawing moment coefficient due to yawing. N r 1 Helicopter main-rotor rpm. 2 Number (FAA). NRA Nuclear reaction analysis, ion-beam technique for light elements. NRAG Non-metallics research advisory group (MRCC). NRC 1 National Research Council. 2 Nuclear reporting cell. 3 Nuclear Regulatory Commission (US, 1974 onwards). NRCS Normalized radar cross-section. NRD Network routing domain. NRDC 1 National Research Development Corporation (UK). 2 Natural Resources Defense Council (US). NRDS Nuclear rocket development station (Jackass Flats, US). NRF NATO Response Force (2002–). NRH No reply heard. NRI Net radio interface. NRL Naval Research Laboratory (USN). NRMM Navaids remote maintenance and monitoring. NRO National Reconnaissance Office (US). NROSS, Nross Navy remote ocean sensing system or satellite (spacecraft, USN). NROTC Naval Reserve Officer Training Corps (US). NRP 1 Normal rated power. 2 Narrow programmable receiver. 3 National Route Program, or Plan (US). 4 Non-return point. NRPA Net return on productive assets. NRPB National Radiological Protection Board. NRR Noise-reduction rating (EPA). NRRC Nuclear-Risk Reduction Centers (1987). NRSC National Remote Sensing Centre (in civil enclave at former RAE Farnborough, UK). NRST Nearest. NRT Near real time [DF adds data fusion, RAS resource allocation system]. NRTS Not repairable this station (USAF). nrv Non-return valve. NRZ Non-return to zero. NS 1 Non-skid. 2 Network service. Ns 1 Nimbostratus. 2 Newton-second, also N-s. ns Nanosecond[s] (10 –9 s). n s Maximum sustained normal acceleration. NSA 1 National Security Agency (US). 2 National Standards Association (US). NSAP Network service access point. NSAR North Sea air-combat manoeuvring instru- mented range. NSAWC Naval Strike and Air Warfare Center (USN). NSC 1 National Security Council (US). 2 No significant cloud. 3 New Scottish [ATC] Centre, Prestwick. NSCA National Safety Council of America. NSDA National Space Development Agency (J). NSDU Network service data unit. NSE Near-synchronous equatorial. NSEU Neutron single-event upset. NSF National Science Foundation (US). NSFAC Non-Scheduled Flying Advisory Committee (CAA, 1945). NSG 1 NATO Standardization Group. 2 North-seeking gyrocompass. NSGr Night close-support group (G, WW2). NSIA National Security Industrial Association (US). NSIU Navigation switching interface unit. NSM Non-contact stress measurement. NSMS Non-intrusive stress-monitoring system. NSMV Near-space maneuvering vehicle (USAF). NSN National [or NATO] stock number[s]. NSNF Non-strategic nuclear forces. NSO Navigation/systems operator. NSOC Naval Satellite Operations Center (Pt Mugu, CA). NSP 1 Normal sea-level power. 2 Night surveillance payload. 3 National Simulator Program; O adds Office (FAA). NSPE National Society of Professional Engineers (US). NSPOL Non-scheduled policy (ECAC). NSR 1 No scheduled removal. 2 Naval [or NATO] Staff Requirement. NSRI National Soil Resources Institute (U. of Cranfield). NPD NSRI 412 NSRP National Search and Rescue Plan (US). NSS 1 National seismic station (US). 2 Near-source simulation. 3 Navigaton subsystem. 4 National Security Space (US). NSSA 1 National Safe Skies Alliance (US). 2 National Space Society of Australia. NSSC Naval Ship Systems Command (USN). NSSFC National Severe Storms Forecast Center (Kansas City). NSSI National Security Space Integration; O adds Office (DoD). NSSL National Severe Storms Laboratory (US). NST 1 NATO Staff Target. 2 Noise, spikes and transients. NSTAC National Security Telecommunications Advisory Council (US). NSTAP National strategic technology acquisition plan (UK). NSTB National satellite testbed. NSTD Non-standard. NSTL 1 National Space Technology Laboratories (NASA, previously MTF, now SSC (4)). 2 National security threat list (US). NSTO Near single stage to orbit. NSTP National space technology programme (DTI, UK). N-strut Interplane or other bracing system having general shape of N. NSVN NATO secure voice network. NSW 1 Nominal specification weight. 2 No significant weather [TAF or Metar]. NSWC Naval Surface Warfare Center (USN). NSWP Non-Soviet Warsaw Pact. nT Nanotesla; terrestrial field varies from c 25,000 (magnetic equator) to c 70,000 nT (poles), vertical compo- nent usually being measured in geophysical prospecting and ASW. nt Nit (name not usually used). NTAOCH Notice to AOC holders (CAA). NTAP Notice to Airmen publication (USGPO). NTAS Norad tactical Autovon system (USAF). NTAT Near-term Acme technology. NTB 1 National test bed (US, SDI). 2 Nuclear test ban; T adds Treaty. NTC 1 National Training Center (US DoD). 2 Numerator time constant. 3 Notice. NTD National Test Director (ISS). NTDD Normalized total departure delay. NTDS Naval tactical data, or distribution, system. NTE 1 Not to exceed. 2 Northerly turning error. NTF 1 No trouble found. 2 NATO task force. NTFWTC NATO Tactical Fighter and Weapons Training Centre. NTG Nachrichtentechnische Gesellschaft im VDE (G). Nth country Next power to possess nuclear weapons (DoD). NTI Next [runway] turn indicator. NTIA National Telecommunications and Information Administration (US). NTIS National Technical Information Service (US). NTK Scientific and technical committee (many in USSR, R). NTM 1 National technical means, of verification of MBFR and precise Earth mapping. 2 NDT manual. 3 NATO Tiger Meet. NTMV National technical means of verification. NTNF Royal Norwegian council for scientific and industrial research. NTO 1 Nitrogen tetroxide. 2 Notice to operators. 3 No technical objection[s]. NTOS No time on station. NTP Normal (ie standard) temperature and pressure. NTPD NTP dry (gas bottle capacities). NTS 1 Negative-torque signal. 2 Navigation technology satellite (USN). 3 Night targeting system. NTSB National Transportation Safety Board (US, from 1966). NTSC National Television Standards Commitee (US). NTT Non-threat traffic. NTTC National Technology Transfer Center (NASA). NTU 1 State technical administration (USSR, R). 2 Navigation training unit. 3 New-threat upgrade. 4 Not taken up [civil registration]. NTW Navy theater-wide; /BMD adds ballistic-missile defense (USN). N 2 O 4 Nitrogen tetroxide. NTWS New threat-warning system. NTZ No-transgression zone. NU Nose-up. Nu Nusselt number. nuclear airburst Explosion at height AGL greater than maximum radius of fireball. nuclear bomber Ambiguous but generally taken to mean aircraft able to deliver nuclear weapons. nuclear capable Nuclear bomber. nuclear cloud All-inclusive term for volume of hot gas, dust, smoke, and other particulate matter from nuclear bomb and environment carried aloft with fireball (DoD, NATO). nuclear column Hollow cylinder of water and spray thrown up from underwater nuclear explosion through which hot high-pressure gases escape to atmosphere (DoD, NATO). nuclear defence Defence against attack by nuclear or radiological weapons. nuclear dud NW which after being triggered fails to provide any explosion of that portion designed to produce nuclear yield (DoD). nuclear emulsion Thick layer used on photo-type plates for recording tracks of energetic particles. nuclear energy That liberated by fission; more rarely, that liberated by fusion reaction, and some definitions include radioactive decay. nuclear explosive Material designed to achieve greatest uncontrolled fission or fission + fusion reaction. nuclear/heater propulsion Using nuclear reactor to heat working fluid for rocket propulsion. nuclear incident Unexpected event short of NWA but resulting in damage to NW or associated facilities or NSRP nuclear incident 413 increase in possibility of explosion or radioactive conta- mination (DoD). nuclear radiation All EM and particulate radiations from nuclear processes. nuclear reactor Device for containing controlled nuclear fission (rarely, fusion) reaction. nuclear rocket Usually one whose working fluid is heated in nuclear reactor. nuclear safety line Line drawn (if possible through prominent topographic features) on map to serve as refer- ence in describing levels of protective measures, degrees of damage and limits allowed for effects of friendly NW. nuclear surface burst One in which centre of fireball is below that height equal to maximum radius. nuclear underground burst One in which centre of detonation lies below original ground level. nuclear weapon One in which almost all released energy results from fission, fusion or both; abb. NW. Original 1945 designs used chain-reaction triggered by critical mass of uranium with unnaturally high concentration of isotope U-235. Second form was based on plutonium Pu-239. Loosely called atomic, or fission, bomb. See hydrogen bomb. nuclear-weapon(s) accident Unplanned occurrence resulting in loss of, or serious damage to, nuclear weapons or components resulting in actual or potential hazard to life or property (DoD, NATO). nuclear-weapon degradation Degeneration of NW to such extent that anticipated yield is reduced. nuclear-weapon employment time Reaction time of NW. nuclear-weapon exercise Exercises involving real NW but excluding launching or flying operations. nuclear yield Energy released in detonation of NW measured in terms of mass of TNT required to liberate same amount: categorized as very low (less than 1 kT), low (1–10 kT), medium (10–50 kT), high (50-500 kT) and very high (over 500 kT). nucleating agent The material released into the atmos- phere in cloud seeding, such as silver iodide. nucleon Particle of atomic nucleus, eg neutron, proton. nucleonics Science of applications of nucleons and atomic emissions. nucleus 1 Particle upon which atmospheric water vapour can condense and/or freeze. 2 Positively charged core of atom. nuclide Member of family of atoms distinguished by having same nucleus (immediately decaying nuclear states are excluded). Nudets Nuclear detonation detection and reporting system; system for surveillance of friendly target areas and immediately providing place, ground zero, burst height and yield of nuclear explosions (DoD, NATO). Nufas NATO uhf frequency-assignment system. Nugget First-tour aviator (USN). nugget Obturator (US, colloq.). NUGP Nominal unit ground pressure. NUI Network-user identification. nuisance malfunction One caused by failure of safety system, eg auto-disconnect of AFCS, main system being serviceable throughout. null 1 Orientation of receiver aerial [antenna] (eg ADF) in which no signal is heard. 2 In DLC, angular setting (usually about 7°) about which spoilers oscillate. 3 Location in space where, at any moment, gravita- tional forces cancel out (eg five centres of libration near Earth/Moon system). nullo Flown without human on board [cockpit- equipped target or other RPV], from ‘no live, or local, operator’. null position See null (2). NUM Nuova unita maggiore, future aircraft carrier (Italy). Numast National Union of Marine, Aviation and Shipping Transport officers (UK). No 1 engine Port outer: engines numbered across aircraft port to starboard. numbers 1 Runway designator. 2 Piano keys, to land on the *. 3 Any numerical data needed for flight, as ‘have *’. numerator time constant Controls rate at which attitude changes result in flight-path changes, symbol T θ 2 . numerical control Control of system, esp. machine tool, by series of commands expressed in numeric (digital) terms giving locations, directions and speeds, and secondary information (eg cutter speed) in correct sequence. Software usually punched paper or magnetic tape. numerical weather prediction Repeatedly refined methods in which powerful computers solve equations and simulate local atmosphere, hence numerical forecast, numerical model. Nunio Network universal input/output [local Ethernet]. NURK Astronautics Society (J). nurse balloon Fabric gas container used as reservoir or to maintain constant inflation pressure in aerostat on ground. Nusselt number Non-dimensional parameter Nu = qD/ λδ T where q is quantity of heat, D is typical length, λ is thermal conductivity and δ T is temperature difference. Nut Near-unity probability. nutating feed Microwave feed to tracking radar in which beam oscillates in one plane while plane of polarization (and usually aerial [antenna] reflector) remains fixed. nutation 1 Oscillation of axis of rotating body (eg gyro). 2 Irregularities in precession of equinoxes and other effects and of rotary precession of Earth’s axis in period of 18.6 years (* period) with maximum displacement of 9.21 s (constant of *). nutator Drive mechanism causing dipole or aerial [antenna] feed horn to gyrate about focus of paraboloidal aerial without changing plane of polarization. nutcracker V/STOL aeroplane whose fuselage hinges near mid-length to vector main-engine thrust. nut plate, nutplate Nut, esp. elastic stop nut, provided with flat-plate base attached permanently to airframe to provide anchor into which attachment bolt can be screwed for securing access panel or other removable item. nut runner Large nut threaded on screwjack so that when either ** or screw is rotated a linear motion results (eg to drive tailplane). NV 1 Naamloze Vennootschap (Netherlands, Belgium, company constitution). 2 National Variants, to FAR-25 and similar. 3 Night vision. 4 Non-volatile. NVCA National Venture Capital Association (US). NVEO Night-vision electro-optics. nuclear radiation NVEO 414 NVESD Night Vision Enhanced [or and Electronic] Sensors Directorate (USA). NVG Night-vision goggles; T adds training. NVIS 1 Near-vertical incident skywave. 2 Night-vision imaging system. NVL Netherlands air transport association. NVLP Netherlands Aerospace Writers Association. NVM Non-volatile memory. NVPS Night-vision pilotage [or piloting] system. NVQ National Vocational Qualification (UK). NVR Netherlands astronautical society. NVRAM Non-volatile RAM. NVS 1 Night-vision system. 2 Noise and vibration suppression [or simulation]. nvt Neutron volts, measure of ionising radiation. NV thrust Nominal vacuum thrust. NVTS Night-vision targeting sight. NVvL Nederelandse Vereniging voor Luchtvaart- techniek. NW 1 Nuclear weapon, or warfare. 2 Nosewheel. NWA Nuclear-weapon(s) accident. NWAA North West Aerospace Alliance; 180+ companies (UK). NWC 1 Naval Weapons Center (China Lake, USN). 2 National War College (US). NWDC Navy Warfare Development Command (USN). NWDS Navigation and weapons-delivery system. NWEF Naval Weapons Evaluation Facility (Albu- querque, USN). NWP Numerical weather prediction. NWPRA National Women’s Pylon Racing Association (US, from 1964). NWS 1 National Weather Service (NOAA, US). 2 Nosewheel steering. 3 North[ern] Warning System (former Dew Line). 4 NW (1) state, or status. NWSSG Nuclear weapon system safety group. NWT Natural work team. NWTS Naval Weapon Test Squadron (NAS Point Mugu). NWV New World Vistas (USAF). NXT Next [K adds track]. ny – Yawing moment coefficient due to sideslip. Nycote Nylon lacquer protective coating. nylon Long-chain synthetic polymer amide with recur- rent amide groups distributed along chain (some definitions add ‘capable of being drawn into filament whose structure is oriented along fibre’). Large family, now often used for 3-D mouldings and many structural purposes (formerly TM for Du Pont de Nemours). nylon letdown Parachute. NYO Not yet operating. N z 1 Normal load factor, ie along OZ axis. 2 AMSU normal-acceleration ouput. NZAF New Zealand Aviation Federation Inc. NZAPA NZ Airline Pilots’ Association. NZAT NZ Airport Technologies (trade association, 19 members). NZCA NZ College of Aviation. NZDF NZ Defence Force. NZG Near-zero growth (tyres). NZGA NZ College of Aviation. NZMAA NZ Model Aeronautical Association. NZMS NZ Meteorological service. NZRA NZ Rotorcraft Association. NZSFA NZ Space Flight Association Ltd. NVESD NZSFA 415 O 1 Opposed configuration (US piston engine designa- tion). 2 Operating cost over given period. 3 Ground speed ‘on’ (onwards from critical point). 4 Observation aircraft category (US services from 1922). 5 Hang-glider category (FAI). 6 Other meanings include odd, over, oxygen and optional. O 2 Oxygen. O 3 Ozone. O-ring Flexible fluid-sealing ring having O-section in free state. OA 1 Output axis. 2 Operational analysis. 3 Observation amphibian (USAAC, USAAF, 1925–47). O/A On or about. OAA Orient Airlines Association. OAAN Organismo Autónomo Aeropuertos Nacionales (Spain). OAB Outer air battle. OAC 1 Operations Advisory Committee (UK CAA). 2 Oceanic Area Control [C adds Centre]. 3 Austrian aero club. OACI ICAO (F). OACS Optically active coding system. OAD Office of Aviation Development [CAA, 1949 on]. OADS Omnidirectonal air-data system (helicopter). OAE Optimized after erosion (helicopter blade profile). OAF Optical-alignment facility. OAFS Open apron, free-standing (ie, no air-bridge). OAFU Observers advanced flying unit. OAG 1 Operational Advisory Group (BATA, USN). 2 Official Airline Guide. OAIRMS Open-architecture integrated radio manage- ment system. OALC Ogden Air Logistics Center (Hill AFB, Utah). OALT Operationally acceptable level of traffic. OAM Office of Aviation Medicine (FAA). OAMCM Organic airborne mine countermeasures. OAMP Optical airborne measurement platform. OAMS Orbital attitude and manoeuvre system. O&C Operations and checkout. O&D Origin and destination. O&I Operations and integration. O&M Operations & maintenance [CM adds configura- tion management]. O&O Organizational and operational (RPV). O&S 1 Operational and support (costs). 2 Operations & Sustainment, of hardware in service (USAF). OANS Observers air navigation school. OAO 1 Orbiting astronomical observatory. 2 Out-of-area operations. OAOI On-and-off instruments. OAP 1 Organizzazione dell’Aviazione Privata e d’Affari (I). 2 Offset aiming point. 3 On-board attitude processor. OAPD Online airline product database (IATA). OAPEC Organization of Arab Petroleum Exporting Countries. OAPP Office of Aviation Policy and Plans (FAA 1). OAPS Oblique air photograph strip. OAR Office of Aerospace Research (USAF and FAA/DoT). OARB Orient airlines research bureau. OARF Outdoor Aerodynamic Research Facility (NASA). OARN Off-airways R-nav. OART Office of Advanced Research & Technology (NASA; now AST). OAS 1 Offensive avionics system. 2 Offensive air support (air support directly linked to land operations, US). 3 Omnidirectional airspeed system (helo). 4 Open-access service. 5 Optimal aircraft scheduling. 6 Obstacle assessment surface. 7 Office of Aviation Safety (CAA). 8 On active service. 9 Oceanic Automation System (FAA/USN). OASC Officer and Aircrew Selection Centre (RAF, Biggin Hill). OASD Office of the Assistant SecDef (US). OASF Orbiting astronomical support facility. Oasis 1 Oceanic and atmospheric scientific information system (NOAA). 2 Operational application of special intelligence system (AAFCE). 3 Omnidirectional approach-slope indicator system. 4 Operational and supportability implementation system (USAF/FAA). 5 Organic airborne and surface-influence sweep. 6 Oceanic Area system improvement study. 7 On-board aircraft server and information system. OASPL Overall sound pressure level. OAST Office of Aeronautics and Space Technology (NASA), more usually AST. Oasys Obstacle-avoidance, or awareness, system. OAT 1 Outside air temperature. 2 Operational acceptance test. 3 Operational air traffic (ie military). 4 Oxide aligned transistor. 5 Operational, or optional, auxiliary terminal (Acars). 6 Operational airfield test set. 7 Orbit and attitude tracking; S adds system. OAV Organic air vehicle. OAVUK Society for aviation and gliding of Ukraine and Crimea. OB 1 Outbound. 2 Balloon club (Austria). 3 Off-boresight. 4 Operations base (USA). 5 Operational Bulletin. O/B 1 Outbound. 2 Outboard. O 416 OBA Outbound boom avoidance (SST). OBAP Organization of Black Airline Pilots (US). OBC 1 Optical barrel camera. 2 On-board computer. OBCO(S) On-board cargo operations (system). Ob.dL Oberkommando der Luftwaffe (G). OBDMS On-board data-monitoring systems. OBE 1 Off-board expendables. 2 Overtaken by events. OBEWS 1 On-board electronic warfare simulation. 2 On-board EW system(s). OBFM Offensive basic flight manoeuvres. OBI Omni-bearing indicator. Obiggs On-board inert gas generating system. OBIS On-board information system. objective 1 Normally, in optical, EO or IR system, first lens or lens group to receive incoming radiation. 2 Military target for capture or other action by surface forces; not used for target for aerial attack. oblique Oblique photograph. oblique camera One mounted in aircraft with axis between vertical and horizontal. oblique photograph One taken by oblique camera; subdi- vided into high * in which apparent horizon appears and low * in which it does not. oblique projection Map projection with axis inclined at oblique angle (say, 20° to 60°) to plane of Equator. oblique-shock inlet Inlet designed for use in supersonic vehicle and provided with centrebody, wedge or other projecting portion intended to focus oblique shockwave on opposite lip. oblique shockwave Inclined shock formed whenever supersonic flow has to turn through finite angle in compressive direction. oblique wing Wing arranged to pivot at mid-point as single unit so that, as one half is swept back, other half is swept forwards. Also called slew wing. OBLMS On-board life-monitoring system. Oboe WW2 precision navaid of SSR type with Cat station near Dover and Mouse station in Norfolk sending synchronized pulses which formed continuous note along correct flightpath over distant target; Mouse operators also sent signals to tell aircrew when to release bombs or TIs. Obogs On-board oxygen generation (or generating) system. OBP 1 On-board processor, or processing [satcom]. 2 Omnidirectional ball panel. 3 Operational build plan. OBPR Office of Biological and Physical Research (NASA). OBR Optical beam rider, or riding. OBRC Operating budget review committee. OBRM On-board replacement module. OBS 1 Omni-bearing selector. 2 Observe/observed/observing (ICAO). 3 On-board simulation. 4 Organizational breakdown structure. 5 Optical bypass switch. 6 Observation-balloon system (tethered near major highway). obs 1 Obstruction lights. 2 Observe[d], observation. 3 Obstacle. Obsc, OBSC Obscure/obscured/obscuring (ICAO). obscuration methods Instrument techniques for measuring visible smoke (eg from jet engine) such as HSU and PSU where cutoff of calibrated light beam is measured over known distance. observation 1 Many military definitions, most agreeing that * platform is for gathering all possible tactical infor- mation about an enemy. 2 Complete set of meteorological readings at one place and time. observation balloon In bygone wars, tethered balloon carrying human who reported on fall of shot and on enemy activity. observation balloon system In US, usually tethered at airfield to monitor potentially conflicting road traffic, eg at runway crossing. observation mirror A horizontal mirror with superim- posed graticule used in the same way as a camera obscura. observed value Measured, not calculated. observer Common title for second crew member in two- seat military (especially combat) aircraft whose functions may include navigation, systems management, electronic warfare, command guidance of weapons and other tasks; title is traditional and may bear no relation to actual duties. OBST, obst Obstruction, obstacle. obstacle clearance height Lowest height above runway threshold or aerodrome elevation used to establish compliance with obstacle clearance criteria in instrument approach. obstn Obstruction (FAA). obstruction Also called obstacle, a real or notional solid body forming hazard to aircraft on or near runway or flight path. For certification purposes has height of 10.7 mm (35 ft) or 15 m (50 ft). obstruction angle Angle between horizontal and line joining highest point of object in flightway [ie, approach path] to nearest point of appropriate runway. obstruction clearance surface Surface in form of plane or flat cone sloping at obstruction angle. obstruction-free zone Free from all fixed obstacles except light frangibly mounted navaids. obstruction light Red light visible 360° on top of object dangerous to moving aircraft in air or on ground. obstruction marker Object of approved shape or colour marking obstruction or boundary of hazardous surface on airfield. Obtex Off-board targeting experiment[s]. obturator Rigid or flexible body tailored to preventing escape of gas under pressure from particular orifice or other leakage path. obturator ring Piston ring of L-section intended to be gastight. OBW 1 On-board wheelchair (for disabled pax). 2 Off-boresight weapon. OC, O/C 1 O’clock. 2 Officer commanding. 3 Over-current. 4 Obstacle clearance (ICAO panel). 5 Optical communications. 6 Obstruction chart. 7 Officer candidate. 8 Oil consumption. 9 On course. OBA OC, O/C 417 OCA 1 Obstacle clearance altitude [suffix H fm , height for finals and straight missed approach; H ps , height for precision segment]. 2 Oceanic control area. 3 Offensive counter-air. OCALC Oklahoma City Air Logistics Center (Tinker AFB). OCAMS, Ocams On-board checkout and monitoring system. OCC 1 Operation[s] [or Oceanic] control centre. 2 Occulting. 3 Occupied [telephone line]. 4 Operator control console. Occar Organisme Conjointe de Co-opération en Matière d’Armément (Int.). occluded front Warm air mass forced aloft by overtaking cold front. occlusion 1 Atmospheric region in which cold front has overtaken slow or stationary warm front and forced warm air mass upwards. 2 Trapping of gas bubbles in solidifying material or by molecular adhesion on surface, esp. removal of gas in high-vacuum technology by a getter. OCCM Optical counter-countermeasures. occultation Complete disappearance of body, esp. source of illumination such as star or aircraft lights, behind another object of much larger apparent size. occulting Flashing, but with illuminated periods clearly predominant. OCD 1 Operational concept demonstration. 2 Oceanic clearance delivery. 3 Office of Civilian Defense (US, 1941). oceanic airspace Controlled airspace over ocean areas. oceanic clearance Clearance delivery to enter oceanic airspace. oceanic navigation error report Filed when surveillance monitor observes aircraft exiting oceanic airspace seri- ously off track. OCF Occluded frontal passage. OCFNT Occluded front. OCH Obstacle clearance height. OCI 1 Outside of clearance indicator (MLS). 2 Out-of-coverage indicator (navaids). OCIG Oceanic communications improvement group. OCIP Offensive capability improvement program. OCL 1 Obstacle [or obstruction] clearance limit. 2 Optimum cruising level. OCLD Occlude. OCLN Occlusion. OCM 1 On-condition maintenance. 2 Optical countermeasures. OCNL Occasional [Y adds occasionally]. OCNR Office of the Chief of Naval Research (USN). OCP 1 Onmnidirectional control pattern. 2 Oceanic clearance processor. OCR 1 Optical-character recognition, or reading. 2 Oceanic control region. 3 On-condition replacement. 4 Office of Commitments and Requirements. 5 Occur. OCS 1 Optimum-cost speed. 2 Officer Candidate School (US). 3 Oceanic Control System (NZ). 4 Obstacle clearance surface. 5 Operational control segment. 6 Officers Command School (RAF Henlow). oct Octane (FAA). octa Unit of visible sky area representing one-eighth of total area visible to celestial horizon, now okta. Octagon Trade-name of a range of de-icing fluids, including potassium and sodium acetates, sodium formate and propylene glycol. octal 1 Standard base for electronic device having eight connector pins. 2 Counting system to base 8. octane number Standard system for expressing resistance of hydrocarbon or other fuel to detonation in piston engine, ranging from 0 (equivalent to n-heptane) through 100 (iso-octane) upwards to about 150. Measures are taken with lean mixture and with rich, latter giving higher values. Also called knock rating (strictly, anti- knock) or performance number, esp. when above 100. See MON, RON. octane rating See octane number. octane test Standard test in which sample of fuel is used to run special variable-compression single-cylinder engine and compared with mixtures of n-heptane and iso-octane, or (above 100 performance number) with other reference fuels. octant Bubble sextant able to measure angles to 90°. octave Interval between any two frequencies having ratio 1:2. octet Complete set of four pairs of electrons forming layers 2 and 3 (in all noble gases except He, outer shell). Octol HE warhead filling, HMX/TNT. Octopus Operational and certified takeoff and landing performance universal software. Octu Officer Cadet Training Unit (UK). OCU 1 Operational Conversion Unit (UK). 2 Optical coupler, or control, unit. 3 Operational capabilities upgrade. 4 Operator control unit (IRCM). oculogyral illusion Apparent movement of fixed objects seen under high-g. OCV Organisme de Contrôle en Vol (F). OCXO Oven-compensated crystal oscillator. OD 1 Outside diameter. 2 Ordnance delivery. 3 Olive drab colour. 4 Optical disk. ODA Overseas Development Administration (UK). Odads Omnidirectional air-data system. Odals, ODALS Omnidirectional approach lighting system. Odapi Omnidirectional approach-path indicator. Odaps Oceanic display and processing [or planning] system. ODC Office of Defense Co-operation (US DoD office in Germany). ODF Operational degradation factor. ODFDMU Optical disk flight-data management unit. ODID, Odid Operational display and input develop- ment. Odin Operational data interface. Odis Operational data interface system. ODL Optical, or Oceanic, data-link. ODM 1 Ministry of Overseas Development (UK). 2 Operating data manual. OCA ODM 418 3 Operational development model. 4 Ordnance deployment manager. 5 Optical driver modem. 6 Original design manufacturer. ODMS 1 Oil-debris monitoring system. 2 Operational data-management system (ATC). odometer Digital readout of numerical quantity, esp. distance, as in DME. ODP Office of Defense Plants (US 1945). ODR 1 Overland downlook radar. 2 Operator difference requirements. 3 Overnight defect rectification. ODS 1 Oxide-dispersion strengthened. 2 Operational debrief station. 3 Optical-disk system. 4 Ozone-depleting substance[s]. 5 Operator, or operator input [and], display system (also OIDS). 6 Office of Defense Supplies (US). 7 Orbit-determination system. ODT 1 Overland downlook technology. 2 Omnidirectional transmitter or transmission. 3 Office of Defense Transportation (US). ODTC Office of Defence Trade Controls (US). ODU Optical display unit. ODVF Society of friends of the air fleet (USSR). ODW Optimum-drag windmilling. OE 1 Opto-electronic (not necessarily synonymous with EO). 2 Over-excitation. OEANC Optical and electronic aiming and navigation complex. OEB Operations engineering bulletin. OEC Operational emergency clearance. OECD Organization for Economic Co-operation and Development (19 member countries). OED 1 Operational evaluation demonstration. 2 Operator-workstation embedded disk. 3 Operational-employment date (UK). OEI One engine inoperative. OEIM Organisme Egyptien pour l’Industrie Militaire. OELD Organic electroluminescent display. OEM 1 Original equipment manufacturer. 2 Office of Emergency Management (US). OEO Operational equipment objective. OEP 1 Office of Emergency Preparedness (US). 2 Operational evolution plan (FAA). OER 1 Operational effectiveness rate. 2 Officer effectiveness report. oersted Non-SI unit of magnetic field strength, = 79.577 A/m, exact conversion is 1,000/4 π . OEST Outline European staff target. OEU 1 Operational Evaluation Unit (RAF). 2 Overhead electronics unit[s]. OEW Operating empty weight [OWE is preferred]. OEX Orbiter experiment; SS adds support system[s] (NASA). OF 1 Over-frequency. 2 Objective Force, major long-term program (USA). 3 Ocean Flight [tower system]; DVPS adds data visual and processing system. O/F Oxidizer (oxidant)-to-fuel ratio. OF 2 Oxygen difluoride rocket propellant. OFA Office Fédéral de l’Air (Switzerland). OFAB HE fragmentation (bomb, USSR, R). OFAM Office Fédéral des Aérodromes Militaires (Switzerland). OFCM Office of the Federal Co-ordinator for Meteorological Services and Supporting Research (US Dept. of Commerce). OFCR Overhead flight-crew rest, in normal wide-body unused above-ceiling volume. OFDM 1 Operational flight-data monitoring. 2 Orthogonal frequency-division multiplexing. OFDPS Oceanic flight-data processing system. OFEMA, Ofema Office Français d’Exportation des Matériels Aéronautiques. off-block time When aircraft leaves gate [probably travelling backwards] or starts to taxi. offboard Released or ejected from the platform [aircraft or ship], usually as decoy. offboard data Supplied by sensors outside the aircraft. off-design 1 Any operating condition other than that or those for which equipment was intended. 2 Less common definition: at or near stall or buffet boundary, or in severe turbulence. offensive avionics Those carried in attacking aircraft to assist fulfilment of mission, eg by providing navigation, target sensing and weapon guidance. offensive sweep Low-level flight by fighters over enemy territory looking for targets of opportunity. office Cockpit or flight deck (colloq.). off-line 1 Connected to computer but not forming part of dedicated controlled sytem. 2 Computer peripheral not directly communicating with central processor. 3 Not on airline’s route network (eg Western Airlines has an * office in Washington DC). 4 Computer or EDP (4) installation which stores input data for processing when commanded. 5 No longer supplying power [usually electric] to system. off-mounted SSR aerial [antenna] not mounted on primary radar but on its own turning gear, and can thus be either synchronized to primary radar or rotated at predetermined data rate. offset 1 In major international purchase, eg of quantity of combat aircraft, agreement in reverse direction in which purchasing country is awarded one or more contracts for products which may or may not be connected with original hardware. This kind of * may be (1) purely window dressing to render costly import less unpalatable, (2) important commercial deal to benefit original importing country, (3) designed to bolster ailing home industry, or (4) important vehicle for transfer of advanced technology to importer. 2 Linear distances, usually small, measured from base- line to joggled or tapered edge, bevel, flange at angle other than 90°, or similar part dimension. 3 Precisely defined point on ground in surface attack (see * bombing) or in space in air interception (see * point). 4 Linear or angular difference beween major axis (eg of aircraft or engine) and axis of drive shaft from gearbox. 5 In fir-tree root, distance between teeth measured parallel to major axis of blade. 6 Length of normal common to landing-gear castor axis and wheel axle [can be zero]. 7 Lateral and vertical distances from desired G/S and ODMS offset 419 runway centreline of (a) an actual landing aircraft, or (b) ILS beam (locus of peak signal strength). 8 Bearing/distance to runway threshold from point navaid, eg Tacan. 9 See * factor). 10 See next. offset angle 1 Angle in vertical plane between horizontal through tug and line joining tug to glider, tow-target or other towed body. 2 Offset (4). offset attack See offset bombing. offset bombing Any surface-attack procedure which employs aiming or reference point other than target. offset distance 1 See offset (2). 2 Distance from desired ground zero or actual ground zero to point target or centre of area target (DoD, NATO). offset factor In parafoil delivery, distance divided by drop altitude. offset frequency simplex Two stations transmit to each other on slightly different frequencies. offset frontal Meeting between two DA (3) aircraft and two hostiles (7–10 miles ahead) on reciprocal, such that no aircraft will pass between opposing pair. offset hinge Helicopter main-rotor hinge at substantial radial distance from axis of rotation. offshore procurement Procurement by direct obligation of MAP funds of materiel outside US territory; may include common items financed by other appropriations (DoD). In other words, US taxpayers paid for aircraft made in Europe, to assist industrial recovery 1951–55. offst Offset track. offtake Route through which power-source physical output is extracted, notably pipe for hot bleed air or shaft for rotary power. off the shelf Already fully developed to military or commercial standards and available from industry for procurement without change to meet military require- ment. off-wing With the engine removed from the aircraft [not necessarily an under-wing installation]. off-wing slide Emergency escape slide well ahead of or behind wing. OFIS, Ofis Operational Flight Information Service (ICAO). OF/NT Operational flight/navigation trainer (USN). OFO Orbiting frog otolith [programme]. OFP 1 Operational flight programme. 2 Occluded frontal passage. OFPP Office of Procurement and Policy (DoD). OFS Operational flying school (RN). OFSHR Offshore. OFT 1 Operational flight trainer. 2 Operational flight test. 3 Operational flying training. 4 Orbital flight test. 5 Office of Fair Trading (UK). 6 Outer-fix time. 7 Office of Force Transformation (DoD). OFTS Operational flight and tactics simulator. OFU Overseas Ferry Unit (RAF, WW2). OFV Outflow valve. OFZ Obstacle-free zone. OG Observation group (USAAC, USAAF). OGA 1 Outer gimbal angle. 2 Office Général de l’Air (F, export distribution). OGE 1 Out of ground effect; supported by lifting rotor(s) in free air with no land surface in proximity. 2 Operational ground equipment. ogee See ogive. oggin, the The sea (RN colloq.). ogive 1 Loosely, any shape formed by planar curve whose radius increases until it becomes straight line. 2 Wing plan having approximate form of curve becoming straight line parallel to longitudinal axis on each side of centreline; so-called ‘Gothic window’ shape. 3 Body of revolution formed by rotation of curve as in (1) about axis parallel to line on same side of line as curve. 4 Any of various other shapes such as conical * (body formed by rotation of two straight lines forming cone/cylinder), tangent * (circular arc tangent to line) or secant * (circular arc meeting line at angle). 5 Common definition is ‘surface of revolution gener- ated when circular arc and line segment are rotated about axis parallel to line’; this is incorrect since curve need not be circular arc and shape can be planar and not body of revolution. OGO Orbiting geophysical observatory. OGV Outlet guide vane, or straightener vane. OGW Space agency (Austria). OH 1 Overhaul. 2 Overhead. O/H Overheat. OHA Operating hazard analysis. OHAR Overhead attendant rest (above ceiling of wide- body centre fuselage). OHC 1 Operating hours counter. 2 Overhauled condition. 3 Overhead camshaft. OHD Overhead. OHM Office of Hazardous Materials (US Dept of Transportation). ohm 1 SI unit of electric resistance, defined as that of conductor across which potential difference of 1 V produces current of 1 A. 2 By analogy with (1), mechanical measure of resistance derived by dividing applied force by velocity; has dimen- sions of g/s. Ohmist, OHMIST Offshore helicopter meteorological information self-briefing terminal. ohmmeter Usually, compact instrument for giving quick approximate indication of resistance of circuit to direct current. OHS Office of Homeland Security (US, DoD, created 2001). OHU, Ohud Optical head, or overhead, unit of HUD. OHV Overhead valve[s]. OI 1 Operational interruption. 2 Office of Information. 3 On instruments. 4 Operating instruction. OIA Office of International Aviation (US). OIB Orbit-insertion burn. OIC 1 Organized immigration crime. 2 Officer in charge. OICRs Operational intelligence collection require- ments. OID 1 Optical incremental digitiser. offset angle OID 420 [...]... over the fence Immediately before touchdown (colloq., normally GA) over the horizon Beyond the visible or LOS horizon; region accessible only to particular species of radar over -the- shoulder delivery See toss bombing over the top On top (1) over the weather At pressurized cruising levels; basic meaning is free from turbulence except CAT, but cloud may still be present and cu-nims must be avoided over the. .. for operational requirements (USN) OTFP Operational traffic flow planning OTH 1 Over the horizon; hence * radar 2 Other OTH-B Over the horizon, backscatter other ranks Soldiers who are not yet NCOs, army equivalent of airmen (UK) OTH-R OTH-R Over the horizon, radar OTH-SW Over the horizon, surface wave OTH-T, OTHT Over the horizon, target[ting] OTIS Optronic tracking and identification system OTLK Outlook... Office of Naval Research (USN) ONS Omega navigation system ONSHR Onshore ONST Outline NATO staff target on the beam Correctly aligned on ILS glidepath or other guidance beam Today has come to mean ‘on the right track’ in most general sense on the deck At minimum safe altitude (colloq.) on the fizzer, on the hooks On a charge, facing disciplinary action (RAF colloq.) on top on top 1 Above unbroken cloud,... American VLF navaid of rho-rho type ONVL Over -the- nose vision line, lower limit in side elevation of pilot’s FOV on-wing With the engine installed in the aircraft [not necessarily hung on a wing] OOA 1 Object-oriented analysis 2 Out of area 3 Offshore Operators’ Association (UK) OOB Order of battle OOD 1 Object-oriented design, or development 2 Officer of the day OODA Observe[r]-orientation-decision-action;... Signal from transducer or other instrumentation 5 Power developed by engine or other prime mover 6 Shaft at which power is extracted from shaft-drive engine 7 Verb, to deliver an * (2), hence outputting outriggers 1 Primary structural members carrying tail of aeroplane with short fuselage, nacelle or boat hull, also called booms 2 Ancillary landing gear near wingtip or at other location well outboard... of dismantling (the extent varying with which *), inspection, replacement of parts if necessary and return to service For large aircraft a major * can take weeks and involve refurnishing and exterior repaint overhaul period Also called TBO, the time between consecutive overhauls For aircraft or engine or other functioning item * is actual operating time in hours For missile and some other items such... succession of inclined shocks at increasingly coarse angles all focused on peripheral lip OT 1 Oil temperature 2 Other times, or over time 3 Operational test OTA 1 Office of Technology Assessment (Congress, US, from 1 972 ) 2 Orbital transfer assembly 3 Over the [or overflight] top attack 4 Other transaction agreement[s] OTAA Office of Trade Adjustment Assistance (US) OTAEF Operational Test & Evaluation... carrying instruments 4 Complete portion of stressed-skin structure, sandwich or, rarely, other constructional form, used for fatigue or static test purposes; not necessarily portion of actual aircraft 5 Subdivision of parachute canopy, either complete gore or portion thereof 6 Body of experts, eg examining * 7 Marking panel panel code Standard code for visual ground/air communication (IADB) panel elements... polygon with rigging lines attached to apices; subdivided into gathered * (periphery constrained by hem cord) and ungathered * parasite Aircraft, invariably aeroplane, which for portion of flight relies on another for propulsion and possibly also for lift Can ride on back of parent, or be attached elsewhere externally or internally, or be towed 4 37 parasite drag parasite drag Sum of all drag components from... like petals of flower PETN Pentaerythritol tetranitrate (explosive) petrol Fuel or solvent tailored from hydrocarbons [eg heptane, hexane, octane] plus additives Density 0 .70 8–0 .72 , giving typical mass 3.93 kg (8.65 lb) gal–1, 3. 27 kg (7. 2 lb) US gal–1, different fractions boil at from 41°C US = gasoline Petroseal A film-forming foam fire-extinguishant Pett, PETT Project engineers & technologists for tomorrow . Over the horizon; hence * radar. 2 Other. OTH-B Over the horizon, backscatter. other ranks Soldiers who are not yet NCOs, army equiv- alent of airmen (UK). oscillator other ranks 428 OTH-R Over the. target. on the beam Correctly aligned on ILS glidepath or other guidance beam. Today has come to mean ‘on the right track’ in most general sense. on the deck At minimum safe altitude (colloq.). on the. temperature. 2 Other times, or over time. 3 Operational test. OTA 1 Office of Technology Assessment (Congress, US, from 1 972 ). 2 Orbital transfer assembly. 3 Over the [or overflight] top attack. 4 Other