Aircraft noise and effects

What is aircraft noise? 

Air noise from aircraft is created by aircraft arriving or departing from airports. It is generally caused by air passing over the aircraft’s airframe (fuselage, wings and underframe) and noise from the engines. Engine noise is created by the sound of the engine’s moving parts and by the sound of air being expelled from the engines at high speeds. The degree of noise generated varies according to aircraft type and size and the way in which the aircraft is flown.

Aircraft manufactured today are generally much quieter than they have been in the past and there are increasingly stringent certification standards for aircraft noise emissions. As a result, the aircraft fleet operating to and from Glasgow Airport is becoming progressively quieter over time. 

In this Noise Action Plan we have also committed to undertake a review of our differential landing charges and other methods of incentivisation to determine if it would be viable to introduce additional measures at Glasgow Airport.

What is ground noise? 

Ground noise is any noise produced by aircraft whilst on the ground and is often related to the following activities:

• aircraft travelling (taxiing) between the runway and stands (where they park), including queuing;
• aircraft at their stands with their auxiliary power units (APU) or ground power units (GPU) running; and
• engine testing (ground running).

Ground noise impacts tend to be limited to those areas closest to the airfield.

Engines need to be tested for safety reasons, and engine running forms part of the maintenance programme for aircraft. We understand that this noise can cause disturbance to residents closest to the airfield and therefore we adopt strict measures to restrict the location, duration and time of day that engine ground running can occur. We do not allow engine ground running above ground during the night, unless required due to exceptional circumstances.

We have introduced new actions in this Noise Action Plan to minimise noise from taxiing aircraft and the noise from aircraft APU/GPUs.

In addition, we have introduced a new action to undertake noise monitoring of engine ground running to better understand its potential impact on our closest neighbours. We will use the information for this monitoring to review our ground running policies and investigate potential further control measures.

How is noise measured? 

Measuring sound and describing its impacts or effects is a complex process. Noise is defined as unwanted sound and some individuals find noise more disruptive than others.

The key metrics used in the Noise Action Plan are summarised below, but we use additional metrics in quantifying noise at Glasgow Airport.

The most common international measure of environmental noise is the L_Aeq, meaning ‘equivalent continuous sound level’. This is a measurement of the total sound energy over a period of time. It is easiest to think of this as an average, but important to note that all the sound energy in the time period is captured by this metric.

In the UK, daytime aircraft noise is typically measured by calculating the equivalent continuous sound level in decibels (dB) over 16 hours (07:00 to 23:00) to give a single daily figure (L_Aeq,16h). 

Night-time aircraft noise is most typically measured over an eight-hour night period (23:00 to 07:00). 

For Noise Action Plans, the Environmental Noise (Scotland) 2006 regulations (as amended) require L_Aeq to be calculated over a full calendar year.

Separate assessment for day and night recognises that daytime and night-time noise can lead to quite different effects (principally daytime annoyance and night-time sleep disturbance) and thus it is better to define and measure daytime and night-time noise separately.

The day evening night equivalent sound level (L_den) noise metric is a 24 hour noise metric that applies a 5 dB(A) penalty to noise during the evening (19:00 to 23:00) and a 10 dB(A) penalty to noise during the night (23:00 to 07:00), reflecting relatively higher sensitivity to noise during these periods.

This metric is used in this Noise Action Plan. 

Go Back To Framework For Developing The Plan

Go To Results Of The Strategic Noise Mapping