Aeronautical Information Publication (AIP) – in aviation, an Aeronautical Information Publication (or AIP) is defined by the International Civil Aviation Organisation (ICAO) as a publication issued by or with the authority of a state and containing aeronautical information of a lasting character essential to air navigation. It is designed to be a manual containing thorough details of regulations, procedures and other information pertinent to flying aircraft in the particular country to which it relates. It is usually issued by or on behalf of the respective Civil Aviation Administration (source: ICAO Annex 14).

Air noise– the noise emitted by an in-flight aircraft while departing from and arriving at an aerodrome. The term air noise includes the noise of the take-off ground roll and the use of reverse thrust after landing. It excludes the noise of taxiing and from all other aircraft and non-aircraft sources within the aerodrome boundaries (which, together, are referred to as ground noise).

Altitude – vertical distance of an aircraft above mean sea level (source).

Annoyance – in everyday speech, annoyance is either understood solely as a feeling (for example, Merriam-Webster (2009) defines it as a 'feeling of slight anger or irritation') or as a "feeling or state" or "being irritated" or experiencing a "nuisance or vexation" (Encyclopædia Britannica, 2010; Oxford English Dictionary, 2012). As observed in surveys, environmental noise annoyance is a retrospective judgment comprising past experiences with a noise source over a specific time period. Noise annoyance usually contains three elements:

1. an often-repeated disturbance of intended activities (e.g. communication) due to noise;
2. an emotional/attitudinal response (e.g. anger);
3. a cognitive response (e.g., distressful insight that one cannot do much against this unwanted situation).

ANP – the international aircraft noise and performance database for noise (source).

Balanced Approach (by ICAO) – this approach aims to address noise problems on an individual airport basis and identify the noise-related measures that achieve maximum environmental benefit most cost-effectively using objective and measurable criteria (source). The four principal elements proposed by the Balanced Approach are:

1. reduction of noise at source;
2. land-use planning and management;
3. noise abatement operational procedures;
4. operating restrictions.

Background noise  – any sound other than the sound being monitored (source).

Continuous Descent Approach (CDA) – also known as optimised profile descent (OPD). CDA is a method by which aircraft approach airports prior to landing. It is designed to reduce fuel consumption and noise compared to other conventional descents. Instead of approaching an airport in a stair step fashion, throttling down and requesting permission to descend to each lower altitude, CDA allows a smooth, constant-angle descent to land.

Contour (or footprint)– a line of constant value of an aircraft noise index around an airport (source).

Decibel, dB, unit of level – measurement on a logarithmic scale of ratio (source).

Dynamic Noise Maps – acoustic maps that illustrate the population noise exposure taking into account spatial and temporal variations in population due to daily mobility patterns of the residents.

Emission Trading Scheme (ETS) – a cornerstone of the EU's policy to combat climate change and its key tool for cost-effectively reducing greenhouse gas emissions. It covers around 40% of the EU's greenhouse gas emissions and works on the "cap and trade" principle. Read more on the European Commission's website.

Environmental Noise Directive (END) – Directive 2002/49/EC relates to the assessment and management of environmental noise. It is the main EU instrument to identify noise pollution levels and trigger the necessary actions, both at Member States and EU level. The END focuses on three action areas:

1. determining the exposure of environmental noise;
2. ensuring that information on environmental noise and its effects is made available to the public;
3. preventing and reducing environmental noise where necessary and preserving environmental noise quality where it is good.

Read more on the European Commission's website.

Environmental Impact Assessment (EIA) – Directive 2011/92/EU is a procedure that ensures that the environmental implications are taken into account before making decisions. It is established to ensure that plans, programmes and projects which are likely to have significant effects on the environment are made subject to an environmental assessment before their approval or authorisation. Consultation with the public is a key feature of environmental assessment procedures (source).

Event – a discrete noise occurrence caused by the passage of an aircraft (source).

Event-related evaluation – for the event-related evaluation, an epoch is defined as the "first aircraft noise epoch". It is when an aircraft noise event starts within 15 seconds of the beginning of the epoch. Then, the noise epoch and the following two epochs are observed for an awakening reaction. As a result, the noise window, which is observed for an awakening reaction, is 90 seconds long.

Exposure-response function – it is the relation between an exposure and the reaction to it (e.g. the relation between maximum sound pressure level of a noise event and the probability to wake up as a consequence of this noise event).

Flight path (or flight track) –the trajectory of an aircraft in flight in three-dimensional space (source).

Focus groups – an in-depth group interview involving a small number of people to discuss and study specific researcher-posed questions.

Ground noise – sound or noise emanating from an aerodrome from sources other than aircraft taking-off and landing. These include aircraft taxiing, maintenance activities, auxiliary power units, surface vehicles and any other sources within the aerodrome boundaries. It excludes the noise from aircraft on the runways and in-flight while departing from and arriving at the aerodrome, which is referred to as air noise (source).

IATA – based in Montreal, the International Air Transport Association (IATA) is a non-governmental entity and trade association that is primarily concerned with the enforcement of private sector standards, emphasising commercial airlines, travel agencies, and consumers. Its purpose is to ensure safety and efficiency for travellers by implementing international standards through its IATA Operation Safety Audit, which is mandated by many governments. IATA has approximately 120 member states and 290+ airlines, representing about 80% of all international air traffic.

ICAO – the International Civil Aviation Organisation (ICAO) is a United Nations Specialised Agency based in Montreal, tasked with governing the standards of international air navigation, transport, and planning. It is the only international organisation with legal authority to implement and revise standards on infrastructure, navigation technology, flight inspections and cross-border procedures for international flights. Its members are the signatories to the 1944 Chicago Convention on International Civil Aviation (currently 193 — all United Nations member states except for Liechtenstein).

ICAO & IATA codes to name airports – although the ICAO and IATA often cooperate to streamline international air traffic, their airport designation is markedly different, and they serve different purposes.

The most apparent distinction between the reporting codes used by the ICAO and IATA is very simple – ICAO code is made out of four letters, whereas IATA code contains three letters. For example, O'Hare International Airport in Chicago, Illinois, USA, is colloquially known as ORD – IATA abbreviation. However, its official reporting code is KORD – ICAO abbreviation. Frankfurt am Main Airport in Frankfurt, Germany is colloquially known as FRA (IATA), whereas its international reporting code is EDDF (ICAO).

Immission – an expression used to describe sound received by an observer (receiver), as opposed to the sound emitted from the source (source).

Impact – an expression used to embrace all adverse effects of noise on people (source).

Interdependencies – noise and CO₂/NO_x emission aircraft relation. Noise-driven regulation has the potential to increase emissions of CO₂and/or NO_X.

Instrument Flight Rules (IFR) – IFR flying means navigating a plane through rough weather conditions, heavy clouds or in the darkness, leveraging cockpit instruments as altimeters, GPS systems and vertical speed indicators (source).

L_den– noise level at day-evening-night. It is a descriptor of noise level based on energy equivalent noise level (L_eq) over a whole day – 24 hours. Adopted by the European Commission, which weights evening noise by an additional 5dB and nighttime noise by an additional 10dB.

L_day, L_evening, L_night– noise level stated at daytime, evening time or nighttime.

LA_max– the maximum sound level reached during a measurement period, expressed in dB(A). However, it does not reflect the number of events, and it does not reflect the amount of energy of each event.

L_{eq_event} – it is the sound pressure level that would be produced by a constant noise level with the same amount of noise energy as the varying noise of the event during the event's duration. This indicator can have different time reference periods: one second, one hour, 24 hours, a year, etc. (LA_{eq_event}, LA_{eq_day}, LA_{eq_24}). It is the most important indicator for airport noise and environmental noise, reflecting the number of events and each event's energy.

Level _ SEL – an important indicator for aircraft noise comparisons but not for the general assessment of airport noise. It is helpful to compare aircraft events. This indicator reflects the total noise energy produced during an event but concentrated in one second.

Low Power/Low Drag – it refers to the configuration and thrust of the aircraft while descending.

Mass– the quantity of matter (in this case, in an aircraft) (source).

Movement – an aircraft departure or arrival (source).

MTOM/W– maximum take-off mass/weight (source).

Noise – noise is often defined as "unwanted sound". The Civil Aviation Authority (CAA, 2018) suggests that laws around noise make it clear that the sound only becomes noise when it exists in the wrong place or at the wrong time. Then, it can cause annoyance, sleep disturbances or other effects. In the context of aviation, airports in more densely populated areas are, therefore, considered to have a greater noise impact, as greater number of people are likely to be affected.

Noise annoyance – it is regarded as a multifaceted psychological concept, covering:

1. the experience of repeated disturbances due to noise and the behavioural response to cope with it;
2. an emotional and attitudinal response to the sound and its disturbing effects; and
3. the perceived loss of control of the noise situation, or in other words, the perceived lack of capacity to cope with noise.

In this way, noise annoyance is not just the response to sound but the judgement of one or more situations in which noise occurs. It means that both acoustic and non-acoustic factors affect annoyance.

Noise Abatement Departure Procedures (NADP's) – procedures for aircraft take-off, designed in a way to cause the least noise while also considering the appropriateness of any of other measures (physical layout of the airport, its surroundings and safety). ICAO doc 8168 contains guidance for the development of a maximum of two noise abatement departure procedures per aircraft, designed generally to mitigate noise either close in (NADP 1) to the airport or further out (NADP 2) along the departure path (source). Essentially, two noise abatement procedures are:

• NADP 1 – aircraft climb to 800 ft+ and then reduce thrust. Aircraft has to keep the flaps lowered in take-off mode and continue climbing as fast as possible to 3,000ft. Then, it has to retract flaps, increase thrust and go further;
• NADP 2 – aircraft climb to 800ft+ and then reduce thrust. At that point, it has to withdraw flaps and continue at a decreased rate of climb until 3,000ft. Then, it increases climb and thrust to go further.

Noise compensation – an action taken to compensate people in situations where noise management and mitigation have failed to alleviate the impact sufficiently.

Noise-induced awakening – sleep stage transition from higher sleep stages to stage awake or sleep stage 1 (i.e. shallow, non-restorative sleep) that was induced by a noise event.

Noise management – an action taken to reduce noise at source or to maximise the horizontal or vertical distance between the noise source and the receiver.

Noise mitigation – an action taken to minimise the transmission of noise from the source to the receiver (for example, sound insulation).

Noise Preferential Route – the departure route from an airport's runway that allows for the minimum noise impact to local communities on the ground.

Noise Preferential Routes or Noise Preferential Configuration –in common use, these routes exist at many airports for managing the noise impacts from aircraft departures.

Non-acoustic factors – situational circumstances or personal state that influence the annoyance judgment besides the mere noise exposure (e.g. an individual's attitude towards aviation, one's general sensitivity to noise). These factors of noise annoyance are regarded as those factors that are supposed to have an impact on noise annoyance but are not directly associated with the sound. In general, personal characteristics and traits, social factors, as well as environmental features, including situational factors, are counted among non-acoustical factors.

Operating procedure– the way in which an aircraft is operated during an arrival or departure from an aerodrome (source).

Polysomnography – sleep study, which includes the recording of the EEG (electroencephalography – brain activity), the eye movements (electrooculography – EOG) and the muscle activity (electromyography – EMG) for the evaluation of sleep in quantity and quality. Polysomnography data is evaluated in a standardised way in 30s sleep epochs.

Quality of life – According to the World Health Organisation (WHO), quality of life is "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns".

Receiver – a recipient of noise arriving from a source; principally at a point (the observer location) on or near the ground surface. The receiver is the one who receives immission.

Runway head – click here for a video thoroughly explaining the meaning of numbers at the head of the runway.

Scenario – an aerodrome case study encompassing all elements and factors involved in a noise impact assessment (source).

SIDs and STARs – a Standard Instrument Departure Route (SID) is a standard ATS route identified in an instrument departure procedure by which aircraft should proceed from the take-off phase to the en-route phase. Also known as tracks or flight paths.

A Standard Arrival Route (STAR) is a standard ATS route identified in an approach procedure by which aircraft should proceed from the en-route phase to an initial approach fix. Also known as tracks or flight paths.

Sleep disturbance – nocturnal aircraft sounds can cause physiological arousals (e.g., awakenings or the transition to a shallower sleep stage, increased heart rate, body movement). If occurring recurrently, these arousals can decrease sleep quality through changes in sleep structure, including problems to fall asleep, early awakenings, reduced deep and rapid eye movement sleep as well as increased wake times (source: Basner et al., 2014).

Sleep parameters

• Sleep period time (SPT) – the time from first to last sleep epoch;
• Total sleep time (TST – SPT) – the time without awake epochs;
• Sleep onset latency (SOL) – the time from light turn-off to first sleep epoch;
• Sleep efficiency (SE – TST) – the time divided by the time in bed (lights turned off);
• EEG-Arousal (EEG) – frequency acceleration with a duration of 3s-10s.

Sound– energy that is transmitted by pressure waves in the air or other materials and is the objective cause of the sensation of hearing. Commonly called noise if it is unwanted (source: Pocket Handbook Noise, Vibration, Light Thermal Comfort”, Brüel & Kjær).

Steep Approach – an approach to landing at an airport that requires a descent along a glideslope angle above greater than the normal maximum of 3.25°.

Threshold – the start of the portion of the runway that is available for aircraft landing (source).

Trade-off – a balance achieved between two desirable but incompatible features (a compromise). A situational decision where one thing increases and another must decrease (trade-offs between noise and fuel-burn – CO2 or NOX).

Technological Readiness Levels (TRL)– a type of measurement system used to assess the maturity level of a particular technology. Each technology project is evaluated against the parameters for each technology level and is then assigned a TRL rating based on the projects progress. There are nine technology readiness levels.

Source: NASA

Virtual Community Noise Simulator (VCNS) – it is a research and demonstration facility to research, evaluate, and demonstrate changes related to operational changes near the airport for communities and other stakeholders. It makes use of Virtual Reality technology to provide users with an immersive environment to experience both audio and visual impact of noise events (more information).

Virtual Community Tool (VCT) – ANIMA's Virtual Community Tool aims to support the mapping of adverse effects of aircraft noise, such as sleep disturbance and community annoyance. This tool is expected to allow policymakers and spatial planners to envision scenarios and associated technologies that could mitigate these effects.

Visual Flight Rules – they exist to ensure that pilots, who are flying visually, would not lose visibility up in the clouds and would not cause accidents.

Weight – the downward force of gravity exerted on an aeroplane. It is essentially proportional to the aeroplane's massand the terms mass and weight tend to be used interchangeably (source).

ACARE – Advisory Council for Aviation Research and Innovation in Europe

ACI –Airports Council International

AIP – Aeronautical Information Publication

ATC – Air Traffic Control

ATM – Air Traffic Management

BA – Balanced Approach

CAEP– Committee on Aviation Environmental Protection

CCO – Continuous Climb Operations

CDO – Continuous Descent Operations

CLEAN SKY – Clean Sky programme

CO₂– Carbon Dioxide

EIA – Environmental Impact Assessment

END– Environmental Noise Directive

EPNL – Effective Perceived Noise Level

ICAO – International Civil Aviation Organisation

IFR– Instrument Flight Rules

ILS– Instrument Landing System.

LP/LD – Low Power/Low Drag

LTO – Landing and Take-off Cycle

LUP– Land-use planning

NADP – Noise Abatement Departure Procedure

NAP – Noise Action Plans

NO_X– Oxides of Nitrogen

NPR – Noise Preferential Route

RWY – Runway

SESAR (ATM) – Single European Sky ATM Research

SID – Standard Instrumental Departure

SNP – Strategic Noise Maps

SRIA – Strategic Research and Innovation Agenda

TRL – Technological Readiness Levels & NRT

VFR – Visual Flight Rules