How we reduce aircraft noise 

Wherever aircraft fly, there will be aircraft noise – from the engines, but also from air turbulence on the fuselage and wings. You
cannot just switch off this noise. But we at DFS are doing everything we can to minimise aircraft noise as much as possible. Modern tools and new technologies help us to do this. 

What DFS does to protect against aircraft noise

aircraft climbing into sky

Aircraft cause noise, through their engines, and through air turbulence on the fuselage and wings. Thanks to modern technology, aircraft have already become much quieter. But especially for residents living near airports, aircraft noise continues to be a nuisance. DFS has only limited influence in this regard. It does not operate any aircraft, nor does it decide on when aircraft fleets are modernised. Nevertheless, noise reduction, or abatement, plays a major role for us. When developing flight procedures, our goal is to keep the noise impact on people to a minimum.

In doing so, we are bound by legal regulations and ordinances issued by the German Federal Government, the EU and ICAO. They provide the framework for procedures planning at DFS. Before publishing new procedures, we consider the vote of the respective Noise Abatement Commission. The German Federal Environment Agency (UBA) is also involved in the review. Ultimately, the German Federal Supervisory Authority for Air Navigation Services (BAF) determines flight routes by statutory instrument. The challenge in planning is to find the best possible compromise. Firstly, the procedure must be safe and suitable for the volume of traffic. Secondly, the flight path should be short and the fuel consumption low. And thirdly, people should be protected from noise as best as possible.

Flight tracks online

Curving flights that stay on track 

DFS is gradually introducing satellite-based departure and approach procedures. In this way, we are increasing the aircraft's track accuracy and ensuring that it is quieter for cities and communities near airports. An international standard has been set for the use of satellite navigation (required navigation performance, RNP). Aircraft that meet this standard are able to fly so-called radius-to-fix curves based on satellite navigation. Pilots fly a highly precise circle with a radius around a reference point determined by the air navigation service provider. This enables aircraft to better maintain their specified ideal track, especially in turns. The prerequisite for this is that the aircraft are equipped with modern satellite navigation technology approved for RNP-1.

aircraft climbing into sky

sunset aircraft approach


Continuous climb and descent

Towns and villages near airports are particularly exposed to the effects of air transport. When designing flight routes, DFS therefore pays special attention to noise-reducing solutions. During landing, a continuous descent approach (CDA) ensures less fuel consumption and less noise. For aircraft taking off, continuous climb operations, or CCO, are a way to reduce the burden of noise. In doing so, the aircraft climbs as steeply as possible to quickly reach cruising level. Because the faster an aircraft climbs, the less audible it is on the ground below the flight path. We developed the CCO departure procedure for Frankfurt Airport as part of the Alliance for Noise Protection. As with the continuous descent approach, the same applies to CCO. It is only possible if the general conditions are right. That means no air traffic is crossing and the weather conditions are favourable.

Individual clearances from a minimum
altitude only

Departures from airports generally follow established procedures, which DFS designs based on ICAO criteria. Up to a specific level, compliance with these fixed routes is a must. Once the minimum safe level has been reached, pilots are theoretically allowed to leave the departure route after consulting air traffic controllers and fly to the next route segment earlier than planned. However, in consideration of the residents in the vicinity of airports, we have undertaken not to give clearance to leave the departure procedure below 5,000 feet. This corresponds to an altitude of 1,500 metres. Individual clearances can also reduce carbon dioxide emissions in cases when they shorten routes, and aircraft burn less fuel as a result.

airplane cockpit during flight

aircraft jet engine

Minimising noise pollution

The most noise is generated when an aircraft takes off. DFS uses the NIROS system (Noise Impact Reduction and Optimisation System) to weigh up which of the flight route alternatives we have worked out is the most favourable. It contains all aircraft types, their technical equipment, geodata and information on the population density of specific regions. Based on the number of aircraft, their performance characteristics and speed, as well as the level in the individual flight phases, the system calculates how long the aircraft will fly over a location. This, in turn, results in an index that indicates how many people hear an aircraft and at what volume. NIROS thus provides a very precise basis for further planning. Whenever possible, densely populated areas are flown around.

Greatest possible accuracy

In order to reduce the impact of aircraft noise, DFS is constantly
enhancing its technical systems. For example, we have developed the GBAS precision approach system, which stands for ground-based augmentation system. GBAS works in addition to satellite navigation and sends correction signals from an additional ground station. This enables precise approaches with a maximum deviation of 15 metres in any direction – a level of precision that satellite navigation alone could not guarantee. GBAS also requires less maintenance than the instrument landing system (ILS), which normally guides aircraft to the runway, and can support a variety of approach procedures simultaneously.

satellite in space


Citizen complaints

As a citizen, do you have concerns or complaints about military flight operations? In such cases, you need to contact the German Air Force directly: 

German Air Force

Are you of the opinion that a civil aircraft is flying lower than usual or not along the usual route? Does the noise level seem to be higher than usual? Do you have questions in this regard? If so, please contact us.