Thanks to additional instrument landing systems (ILS), aircraft on the Northwest Runway have been able to land at a higher glide angle of 3.2 degrees since 2012. The usual ILS glide slope of 3.0 degrees only has to be utilized in the event of adverse weather conditions. Since then, pilots have usually been able to fly higher over the cities of Flörsheim, Frankfurt-Süd and northern parts of Offenbach.

Since March 30, 2017, ground-based augmentation system (GBAS) technology at Frankfurt Airport has allowed landings at a steeper approach angle of 3.2 degrees on the two other runways (South and Center Runways) as well, provided that the aircraft landing is equipped for GBAS and that pilots have the appropriate licenses. Since then, the cities of Offenbach-Süd, Raunheim and Bischofsheim have also been flown over at a higher altitude.

This method has been a part of standard operations since October 17, 2013. It means that Frankfurt Airport can be approached on a near continuous descent. This allows for engines to be left idle for as long as possible.

The descent typically begins at approximately 10,000 feet (3,000 meters) and reduces the noise footprint in areas around 30 to 75 kilometers away from the airport. The method reduces noise, saves fuel and cuts exhaust emissions. 

As continuous descent requires a greater distance between the approaching aircraft, this method cannot be used, or can only be used to a limited extent, when there are heavy traffic volumes or adverse weather conditions.

GBAS is an approach technology that enables precision approaches without requiring an instrument landing system (ILS). The use of GBAS improves flight path accuracy during approaches and generally enables approaches at an even steeper approach angle than 3.2 degrees.

Like the ILS, the GBAS technology can now be used on all runways, including for independent flight operations (with simultaneous landings on parallel runways). To use GBAS, aircraft require the corresponding equipment and the pilots must have an appropriate license.

Generally, all newer aircraft, e.g. the Airbus A380, Boeing 747-8 or B787, are able to use the GBAS system. However, not all airlines have the expensive equipment that this procedure requires on board as yet. The GBAS utilization rate at Frankfurt is therefore only 10 percent, though this is higher than at other airports.

In conjunction with the current active noise abatement program, the Airport and Region Forum is considering raising the intermediate approach altitude so that GBAS landing approaches can be longer and higher than has been the case to date.

Since 2011, in order to enhance noise abatement for densely populated communities during the final approach, Frankfurt Airport has been using a satellite-aided approach procedure known as “segmented approach RNP.” In other words, an approach broken down into curved segments. To enhance noise abatement for densely populated communities under the final approach, approaching aircraft use required navigation performance (RNP) rather than the ground-based beacon and align with the extended runway centerline at a later point.

The segmented approach contributes to noise abatement for the communities of Offenbach, Hanau and Maintal for westerly movements and Mainz and Bischofsheim for easterly movements. However, this means an increased footprint for other, less densely populated regions such as Heusenstamm and Obertshausen (west) and Rüsselsheim-Bauschheim (east).

Until February 2021, only delayed flights arriving after 11 p.m. used the segmented approach.

On March 1, 2021, a trial phase began with the aim of expanding the use of the segmented approach procedure, ideally between 10 p.m. and midnight. The use of the segmented approach requires that there are no impediments, such as snow, storm conditions or unexpectedly high traffic.

The third test phase began on December 15, 2022. DFS German Air Navigation Services uses the segmented approach procedure for inbound flights from all directions. An extension of the trial will see the procedure being systematically published for pilots on the Automatic Terminal Information Service (ATIS) even before 10 p.m. The aim of this is to establish segmented approaches as the primary method to be used from 10 p.m. to midnight.

During this test phase as well, FFR is monitoring flight procedures for precision and noise optimization in addition to overseeing noise calculations.

Optimized segmented approach: RNP to xLS

This procedure examines the possibility of using a segmented approach in which the curved path is flown much more precisely with the assistance of additional precision procedures, such as RNP1 and RF legs. This would mitigate the noise footprint in the areas concerned.

Frankfurt Airport tested the segmented approach RNP to xLS in 2016 and founded it to be viable in principle in terms of operational and flight considerations. However, it can only be implemented in the longer term as very few aircraft today have the technical equipment necessary.

Segmented approach – independent segmented parallel approach research project

Today, segmented approaches are only possible during what is known as “dependent runway operation”. This means that controllers at DFS German Air Navigation Services have to coordinate landings on the Northwest and South Runways to ensure that a minimum distance is maintained between the aircraft approaching the two runways. The required high level of coordination means that segmented approaches are only possible when traffic volumes are low.

Therefore, the research project also examined the technical and flying requirements for applying segmented approaches during “independent runway operation” as well, i.e. so that this procedure can be used all day.

The redirection of the “AMTIX Short” departure route is a key issue within the current program of measures. The objective is to redirect flyovers above Darmstadt to less densely populated areas in order to enhance noise abatement for densely populated areas in the north of Darmstadt, in particular Arheilgen and Kranichstein.

As this change would also increase the degree to which residents in northern residential areas in the Darmstadt-Dieburg district are affected, there has been a public discussion of the ways that the route could be redirected in conjunction with a consultation process. This is a dialog engagement initiated by the FFR and the Frankfurt Aircraft Noise Commission (FLK) for the first time that includes the concerned communities of Erzhausen, Darmstadt and Weiterstadt.

Following the successful conclusion of the consultation process, a trial phase began on November 5, 2020, for the northern redirection of AMTIX Short in line with the flight route variant “3 New”. However, this trial was halted early on January 29, 2021 due to possible safety risks. The “old” departure route has been used again since that time.

The reason for suspending the trial was that some aircraft were unable to follow the new route instructions around Messel with sufficient precision, and in isolated cases they entered the adjacent approach sector to the east of Darmstadt.

In the interim, the FFR’s expert panels have devised solutions for the potential conflict between departures and arrivals. DFL German Air Navigation Services has developed new redirection options for AMTIX Short that are currently undergoing noise calculations. The FFR expects to discuss the new options in late 2023. The Aircraft Noise Commission would then deliberate any positive recommendation approved by the FFR.

The aviation industry is presently undergoing a significant technological transition, involving a move away from navigation using signal stations on the ground towards precision flying with satellite signal support. Required navigation performance (RNP) enables precision flying and, in conjunction with radius-to-fix/RF legs technology, allows curves to be flown much more accurately.

From 2024, all European airports will be required to offer corresponding RNP departure routes to all aircraft. This transition was much faster in Frankfurt. According to EU demands, European airports should firstly offer at least one RNP route from every runway by 2024. Frankfurt Airport had already implemented this by the end of 2019.

Secondly, European airports are required to switch all routes to performance-based navigation (PBN) by 2030 (RNAV or RNP). Frankfurt Airport is working on this, among other things, in the next PBN package, which is to be implemented in July 2024. This package of measures will be followed by others leading to 2030.

Improved directional stability on “southern bypass” and “07-South Long” departure routes with RNP and RF functionality before 2024

In the past, aircraft have frequently deviated from the curve on the southern bypass (western departure route), for instance near the community of Trebur. On the 07-South Long departure route (east departure route) as well, there have been deviations from the curve near Heusenstamm. With the state-of-the-art precision flying procedure RNP and fixed curve radiuses (radius-to-fix/RF legs), appropriately equipped aircraft will now be able to fly the above two departure routes with greater precision, even under adverse wind and weather conditions.

At present, not all aircraft are equipped to use RNP1 and RF legs procedures. However, their share is growing and noise abatement along these departure routes will become even more effective moving ahead.

There are strict regulations governing test runs with higher engine thrust as “idle.” The rules are even stricter at night than during the day. An engine testing facility lying to the south of the airport grounds protects nearby residential areas from noise emissions during test runs. Test runs during the night with engines running on full are only permitted in this facility.

As reverse thrust at higher levels may constitute a disruptive noise event for nearby residential areas, automated acoustic monitoring is used to counteract unwarranted use of this system and thus to reduce disturbances.

Aircraft can be supplied with electrical ground power at all parking positions, hence they do not have to run their own auxiliary power units (APU). However, their aircraft still has to maintain temperature control when outside temperatures are particularly high or low. This means that the APU has to be switched on if preconditioned air (PCA) is not introduced from the outside using PCA units. PCA technology is currently being tested at Frankfurt Airport.

Continuous monitoring of aircraft noise reduction research is a key requirement for sustainable abatement development, as are cooperation with the state and federal governments, support for funding programs and the creation of further incentives for more noise mitigation.

The FFR aims to simplify the German Air Traffic Regulations (LuftVO, Luftverkehrsordnung) to allow for a simpler and quicker testing of new procedures.

This concerns the establishment of a national group of active noise abatement experts. Through the strict documentation of tested measures, this panel would be able to make decisions more quickly and for all German states on which measures make sense and at which locations.