FAQ, most frequent myths and noise-related questions

The Enviroment


When and where is air-traffic noise from Prague-Ruzyně airport operation measured?

Noise is monitored throughout the year, non-stop at 13 locations around the airport. The map of the places of measurement is available here.

Moreover, two mobile instruments are also used for noise measurement as needed. For the requirements of Prague Airport, these 15 measurement instruments are operated by the accredited testing laboratory, MaREXCOM. The results are presented to the relevant public health authorities (the Regional Public Health Office of the Central Bohemian Region and Public Health Office of the Capital City of Prague) and are available on the website here.

Prague Airport also has a two-channel analyser at its disposal which is intended not only for the classical measurement of outdoor protected areas, but also for measuring the difference between the exterior and interior and finding out whether the limits for protected interiors are being met.

How is noise from air traffic evaluated?

Noise from air traffic is evaluated by the “equivalent level of sound pressure A related to a characteristic air-traffic day”. This is the average level of sound pressure A of the number of transfers per average air-traffic day in the period from May to October including all-year runway distribution. Separate evaluations are prepared for daytime and nighttime, as mentioned later.

What are the health limits for noise from air traffic and what are they related to?

Basically, there are four limits which can be divided by type of protected area as well as by time of day as follows:

Equivalent level of sound pressure A in relation to CHATD

DaytimeOutdoor protected zone and outdoor protected zone of buildings outside the NPZProtected interior of buildings everywhere
Day (06 – 22) – LAeq,D,CHLD60 dB40 dB
Night (22 – 06) - LAeq,N,CHLD50 dB30 dB


What is a Noise Protection Zone (NPZ)?

The NPZ is a precise delimited area in the vicinity of the Airport where the exceeding of health limits for noise from air traffic is expected in the outdoor protected zone and outdoor protected zone of buildings over the rather long term. The Airport operator is obliged to ensure that the health limits for noise are observed at least inside buildings in this zone. So far, this has been fulfilled by the blanket replacement of windows, see Noise Protection Zone of Prague-Ruzyně Airport. As a measure of a general nature, an NPZ is declared by the respective building authority.

What does a runway designation look like and what does the designation indicate?

Podrobnosti ohledně značení dráhového systému naleznete zde:

Noise Air Traffic and Noise Airport Operations.

Why do aeroplanes sometimes keep taking off over my house, whereas sometimes they keep landing?

A clear and detailed explanation is provided here:

Noise Air Traffic and Noise Airport Operations.

Looking out of the window, we can see clearly that it is not windy – why has traffic been transferred to the opposite direction, which exposes us to a kind of noise we are not normally used to?

Due to specificities of the landscape and buildings in the surroundings, the speed and direction of the wind may considerably differ from the readings of ground wind at the airport, which is free of marked unevenness of surface with all the buildings situated quite far from the runways.

No matter how important the direction and speed of the wind are when choosing a runway, other factors also play their role. These include:

  • Storm clouds near the threshold of the opposite direction of a runway.
  • The bottom base of clouds, fog and similar meteorological phenomena make the safe approach from a given direction of a runway impossible. Based on forecasts by aviation meteorologists, the Air Navigation Services turn the air traffic to a more convenient direction as a precaution, although the readings have not yet exceeded the tail wind thresholds.
Why did aeroplanes fly over Prague or, on the contrary, over the northern outskirts of Kladno, when the primary runway was under general overhaul in the 2012 and 2013 seasons?

Short-term transfer of traffic from the primary runway (RWY06/24) to the secondary runway (RWY 12/30) can happen unexpectedly at any time of the year. The most frequent causes are:

  • Strong side wind on the primary runway exceeding or forecast to be soon exceeding 15 kt (28 km/h).
  • Primary runway is contaminated by rainfall or snowfall, considerably worsening braking efficiency Defect/failure of technical equipment or minor damage to the RWY surface requiring an unplanned repair.
  • Landing over Prague (landing on RWY 30) is allowed, in parallel to operation on the primary runway 06/24, for aircraft of a maximum take-off weight not exceeding 5.7 t.
  • Vzlety přes Prahu (vzlety z dráhy 12) mohou souběžně s provozem na hlavní dráze provádět vrtulová letadla nebo proudová letadla o maximální vzletové hmotnosti do 5,7t.
  • This means quiet planes that climb very easily.
  • Take-offs and landings near the northern outskirts of Kladno can occur during daytime, with any type of aircraft. Thanks to the general overhaul, the regular pre- and post-season maintenance has shortened to a minimum, because time-consuming repairs are not needed, unlike merely removing rubber fragments from the runway, topping repairs or renewals of runway markings, etc.

From the perspective of year-round statistics, these situations happen only rarely. The following graphs show the percentage of traffic in each year, in the daytime and nighttime. The traffic also includes aeroplanes which can use the secondary runway RWY 12/30 even under standard conditions (small jet planes not exceeding 7 t or propeller planes). We can notice anomalies in 2012, 2013 and 2016 in the graphs when the primary runway RWY 06/24 was closed due to construction work either partially (2012 and 2016) or entirely (2013).


Is the current traffic information and meteorological data available to the public?

Yes, the reasons for any current transfer of traffic are described in a simplified form on the website of Letiště Praha, a.s. The information is always published with some delay.


If you are interested in detailed and up-to-date operational information, you can find it on the website of Air Navigation Services or the website operated by Letiště Praha and designed especially for crews providing them with ATIS messages (ATIS – LKPR), weather forecasts or current METARs and NOTAMs.

ATIS = Automatic Terminal Information System – continuously broadcast recording containing crucial information especially for aircraft crews; for details see below.

METAR = message d’observation météorologique régulière pour l’aviation – “Regular meteorological message for aviation”, containing important meteorological information (wind, visibility, or significant meteorological phenomena) recorded in a single international code.

NOTAM = Notice To Airmen – Notices spread using telecommunications containing information about an establishment, status or change of any aviation facility, service or procedures or about risks, the timely knowledge of which is necessary for staff dealing with air traffic.


The most frequent myths

Aeroplanes fly lower than they did in the past

Over the localities situated on the final approach axis, the altitude of aeroplanes which are about to land is actually the same, with minimum variances after reaching the final approach axis which takes place in the area over Bořanovice up to Zdiby. The aircraft land at an angle of 3° so that they can be approximately 17 m over the threshold of the runway in question (RWY 24). Highly accurate radio navigation is used for landings (usually ILS technology) and the overall settings of the aeroplane are adjusted during landing so as to be smooth and safe in the TDZ (touchdown zone) of a given RWY. Therefore, the trajectories of all landings are almost identical. The 3-degree angle of landing has been applicable to Prague Airport for many years, while over the course of time, the accuracy of radio navigation technologies has improved further.

The situation in terms of take-offs is different. The performance of various types of aircrafts differs significantly and the load of the aeroplane and current weather conditions also play their role. These are the reasons for different altitudes of the planes taking off over particular localities near the airport, despite the fact that the steps taken to adjustment the aircraft after take-off are in accordance with the Procedure for reducing noise at take-off specified in the aviation information manual. Over the course of the year, changes take place which are reflected in the rate of climb of aeroplanes. For example, higher summer temperatures (lower engine performance) in conjunction with the higher number of passengers on some flights can cause a slightly worse rate of climb of the same aeroplane when compared with wintertime. Nevertheless, such phenomena are repeated naturally every year.

Pilots fly wherever they want, not observing the procedures

Pilots are not allowed to fly wherever they want. Air traffic is monitored and controlled by the Air Navigation Services, in particular with regard to its maximum safety. The aviation information manual lists the take-off and landing trajectories and procedures applicable to landing and take-off, set with respect to minimising the noise burden to the population. Nevertheless, it is possible to depart from these procedures if this is required by air traffic safety, which has priority over the noise protection rules.

Aeroplanes are not allowed to fly at night

The air traffic at nighttime, i.e. from 10 p.m. until 6 a.m., is limited by the extent of the Noise Protection Zone, when it is not allowed to exceed the health limit for noise from air traffic in this zone. The extent of the NPZ corresponds, on average, to 48 take-offs and landings. This is how the traffic is planned for the nighttime. This is an important traffic regulation when compared to the daytime.

Air Navigation Services and Prague Airport make an economic profit from the non-observance of anti-noise procedures.

No profit is generated for Air Navigation Services and Prague Airport from non-observance of anti-noise procedures. There is no link between the anti-noise procedures and the income of Air Navigation Services and Prague Airport. To name just one classic example, we can mention “runway preference” which is an important anti-noise procedure mentioned in the aviation information manual. RWY 24 is preferred for noise prevention reasons, because noise from air traffic when using this runway affects the lowest number of people and this runway is also the best from the perspective of runway passableness. Furthermore, its use provides the smallest room for errors in terms of the organisation of air traffic both in the air and on the ground on taxiways. Therefore, there is no logical reason for an intentional change to another runway by the Air Navigation Services. The same applies to other noise-reducing procedures.

Noise-related questions

  • Do you live in an area affected by air traffic and do you still have questions even though you have read the information on our website?
  • Are you moving in an area close to Prague-Ruzyně Airport and are u interested in the intensity and noisiness of the air traffic in the given location?
  • Are you interested in the noise level of the air traffic and air traffic organisation at the location of your current or planned home after the construction of the parallel runway RWY 06R/24L?

Ask us a question by emailing zivotni.prostredi@prg.aero.