Questions en answers on Rotterdam route change

Why is a change needed?

In the past, most of the traffic at the Rotterdam airport consisted of propeller-driven aircraft and small jet aircraft. Over time, because more and more jet aircraft are using the airport, it has become increasingly clear that the present departure route to the North East, then turning to the South West, is not suitable for larger jet aircraft, which make a wider turn than the standard departure route prescribes.

Making a wider turn than is prescribed for the above standard departure route could mean that aircraft taking off from Rotterdam could fly closer to the traffic for Schiphol than is desirable from the point of view of aviation safety. Because the number of jet aircraft using Rotterdam airport is increasing, the potential risk of interference with traffic landing at Schiphol is increasing along with it. For Schiphol, this applies for traffic landing on the Kaag runway and for traffic that uses parallel approach procedures from the South to the Zwanenburg and Aalsmeer runways.

For that reason, Air Traffic Control The Netherlands (LVNL) previously announced a temporary measure, which is still in effect at present. Aircraft taking off from Rotterdam in a North-Easterly direction and turning South-West will receive instructions from air traffic control to fly straight on up to 1,500 feet (about 500 meters) and then start the turn to the West to follow the regular route.

The change in the given departure route from 12 November 2015 is part of the definitive solution for the problem described above. The new route ensures that the traffic will ‘spread out’ less over the surrounding area. It also means stable, predictable traffic flows once more for air traffic control.

What does the temporary measure involve?

Under the temporary measure, aircraft flying West and which take off towards the North East will now receive instructions from air traffic control to climb straight on to an altitude of 1,500 feet (about 500 meters) and when passing this altitude, to start the left turn in order to then follow the regular departure route. As a result, the aircraft that follow this route will turn sooner (and at a lower altitude) above Lansingerland. All other departure routes remain unchanged.

In the past, most of the traffic at the Rotterdam airport consisted of propeller-driven aircraft and small jet aircraft. Over time, because more and more jet aircraft are using the airport, it has become increasingly clear that the present departure route to the North East, followed by a turn to the South West, is not suitable for larger jet aircraft, which make a wider turn than the standard departure route prescribes.

Making a wider turn than is prescribed for the above standard departure route could mean that aircraft taking off from Rotterdam could fly closer to the traffic for Schiphol than is desirable from the point of view of aviation safety. Because the number of jet aircraft using Rotterdam airport is increasing, the potential risk of interference with traffic landing at Schiphol is increasing along with it. For Schiphol, this applies for traffic landing on the Kaag runway and for traffic that uses parallel approach procedures from the South to the Zwanenburg and Aalsmeer runways.

There have been no serious incidents so far and air traffic control has been using this route for years now. How is it that this has not led to a serious incident yet? Or have there been some that we have not been informed about?

So far, air traffic control has solved potential conflicts in good time. The temporary measure has ensured that the risk of incidents has been reduced further. Nowadays, safety must also be verifiable in procedures. In addition, with the increase in air traffic, it is becoming increasingly difficult for air traffic control to work in the ‘old’ way, due to the mutual coordination of flights.

If serious incidents occur, these are published on the LVNL site and are always reported to the Dutch Safety Board.

Will the safety risk have disappeared once this new departure route has been introduced?

Yes, the introduction of this measure will solve the potential safety risk.

Why will the temporary measure still be used at some points after 12 November 2015?

In order to solve the potential safety risks completely, a change must also be made in the procedures for the parallel (i.e. simultaneous) approaches to the Zwanenburg and Aalsmeer runways at Schiphol. Because this requires a very extensive change, the introduction of this solution unfortunately will take more time and it cannot be introduced at the same time as the new departure route from Rotterdam. A change in the air traffic control system will be made on 12 November (this can be done only twice a year), so that once all the investigations are complete, the required process steps have been taken and the air traffic controllers concerned have been trained in the new working method, the change can be introduced fairly quickly.

How does such a process work?

After the need for a change has been observed, if there is a safety issue, a temporary measure is introduced first, which immediately reduces the safety risk. Investigations are then conducted into the potential permanent solution, taking account of any consequences for the environment (including avoiding residential cores as far as possible). Once a solution has been found, this is investigated theoretically in terms of air traffic control aspects. The parties concerned are then informed about the changes. If a choice is made for the best variant, the remaining studies of the feasibility of its execution are conducted. These are generally detailed studies and checks in the air traffic control and flight simulators, so that it is certain that the solution found will also meet all the requirements set in practice.

What does the new route look like?

Rotterdam

The difference between the new route and the old route (unbroken green line) is that the turn starts earlier and is wider, so that larger aircraft can also fly this properly.

The new route is defined in two ways:

  • The description of the route without a fixed turn radius (blue line)

This is a description of the route that can be flown by all air traffic, with both modern and conventional equipment on board. Because not every aircraft has the same flight performance, a spread of flight paths will arise.

  • The description of the route with a fixed turn radius (red line).

In order to be able to fly this route, the aircraft needs modern equipment in order to fly an accurate pattern along a defined fixed route. The spread of traffic on the red route will be minimal, because this will be flown far more precisely. The route has been designed for medium-weight jet aircraft with good climbing performance, so that the aircraft quickly reach an altitude of 3,000 feet.

Why is the new route drawn as it is?

When a new flight route is designed, there are a number of set principles. A new route must comply with a great many conditions. Among other things, it must be technically possible to fly these well and enough of the adjoining airspace must remain free, with sufficient distance from other traffic flows. The turning radius must also be enough to enable all aircraft to fly the route. At the same time, efforts are made at the start of the design process to avoid built-up areas as far as possible, so that the noise from aircraft taking off is limited as much as possible.

During the design phase of the new departure routes from Rotterdam, two design variants were developed, both with and without a fixed turn radius. After consulting representatives of the municipal authorities involved, LVNL made a choice for one of the design variants (the blue and red lines in the diagrams).

In the ADECS Airinfra report, the two design variants (each described in two ways) were compared with the existing routes. 

Do the aircraft fly precisely along the lines drawn? 

With the route with no fixed turn radius (the blue line), there will be a reasonable spread, as flying takes place here via a number of pre-defined points. Each type of aircraft does this in its own way. The wind has an influence of the ultimate flight path here.

The route with the fixed turn radius (the red line) will be quite reliable. Ultimately, there will also be some spread here, but this will be minimal in comparison with the spread around the blue line.

How high do the aircraft fly?

The map shows the altitudes between which the air traffic will fly on the new route. This altitude depends partly on the climbing performance of the aircraft, the weather conditions and the other air traffic in the area.
 

Is there a link with the new Airports Decree?

Together with the need for LVNL to adjust the route, a new Airports Decree is being developed for RTHA (this is a mandatory statutory requirement). An EIR will be drawn up for this, in which noise calculations will be made. The data for the new route are already being used in these calculations. There is no other link with the new Airports Decree.

What will this mean for each municipality?

In itself, the change does not require any noise calculations, because the noise levels fall within the contours fixed in the Airports Decree. However, on its own initiative, LVNL nevertheless commissioned the ADECS Airinfra agency to make these calculations, in order to give the municipal authorities concerned more insight into the shift in the noise patterns. ADECS Airinfra included the results of these calculations in the attached report. This contains more background information on the different noise contours, the legal framework and the number of persons who suffer inconvenience.

With regard to the differences in the relevant statutory contours (48 Lden and 56 Lden), it was concluded that both design variants show almost no shifts. With regard to nuisance, it can be concluded that there is a shift in noise levels and the number of persons who suffer ‘serious inconvenience’. These consequences arise through the earlier turn to the left on the new departure routes from Rotterdam in comparison with the current routes.

The figures for the number of persons who are ‘seriously inconvenienced’ (statutory calculation variant) in each municipality present the following picture:

‘Published routes’ refers to the routes in use in the ‘old’ situation, until 12-11-2015. ‘Variant 1’ was ultimately taken into use as a new route.

The differences between design variant 1 and 2 are minimal. For this reason, ADECS Airinfra reached the conclusion that no distinction can be made between the two variants on the basis of noise levels.

The design variant that took effect on 12 November 2015 concerns Variant 1.

Will there now be different or more air traffic?

No, this change to the departure route will not affect the composition or the volume of air traffic.

How did the process with the municipal authorities proceed?

Because the change involves a significant alteration to the flight paths, LVNL organised a meeting for representatives of the municipalities that will be affected by the new routes. The relevant municipal authorities had a preference for being permitted to express a view in favour of one of the possible design alternatives. Unfortunately, something went wrong in this process, as a result of which the Pijnacker Nootdorp municipal authority was not present at this meeting. Shortly after this information session, LVNL conducted talks with representatives of the Pijnacker Nootdorp municipal authority after all. The Regional Consultative Committee was also informed. 

Who will take the final decision on the introduction of this route?

The design produced by LVNL has been submitted to the Ministry of Infrastructure and the Environment and the Ministry of Defence for assessment. Ultimately, the Ministers concerned consented to the introduction of the new route.

Does a new EIR have to be produced for this?

Because the new route is already included in the calculations for the new Airports Decree, no new Environmental Impact Report (EIR) has to be produced for this.

Why have noise calculations been made?

In itself, the change does not require any noise calculations, because it falls within the contours fixed in the Airports Decree. However, on its own initiative, LVNL commissioned the ADECS Airinfra agency to make these calculations, in order to give the municipal authorities concerned more insight into the shift in the noise patterns. The results of these calculations are now known and are included in the attached report.

Are there also places in which the noise levels will be lower? Will there be more noise at ground level?

Because the route will be changed, this involves a shift in the noise patterns. This means that more noise will be audible at some locations and less at others.

In its report, ADECS Airinfra recorded the following shifts:

In terms of number of residential properties:

‘Published routes’ refers to the routes in use in the ‘old’ situation, until 12-11-2015.

‘Variant 1’ was ultimately taken into use as a new route.

In terms of the number of persons suffering serious inconvenience:

 ‘Published routes’ refers to the routes in use in the ‘old’ situation, until 12-11-2015.

‘Variant 1’ was ultimately taken into use as a new route.

The design variant that took effect on 12 November 2015 concerns Variant 1.

How much use will be made of the new route?

The new route replaces the old one and will in principle be used just as often, i.e. for about 1.4% of the Rotterdam The Hague Airport (RTHA) air traffic.

In 2014, a total of 1,009 flights took off along the relevant departure route from runway 06 in Rotterdam. This was 7% of the total Rotterdam traffic in 2014. Of this 7%, 19.8% took off (from runway 06) in 2014 to fly via the route in question.

This varies daily, up to a maximum of 17 take-offs in 2014. The average for that year was 2.8 take-offs per day. The figures for the year before, 2013, were a maximum of 16 take-offs in a day and an average of 3.1 take-offs per day.