Background and objective of the notice
The new regulations are based on the Air Traffic Regulations and concretise the procedures of DFS to ensure a high level of safety. Stable and safe airport operations with low visibility. The focus is on:
- Protection of ILS signalling systems against interference
- Execution of IFR approaches and take-offs with low visibility
- Ground movements under announced low-visibility conditions
- Assignment of airport locations to specific ILS categories
DFS is pursuing the goal of Operational safety under IMC conditions and at the same time ensure that ILS signals not affected during critical phases for example through vehicle movements or incorrectly instructed aircraft.
Scope of application and affected airports
The regulations apply to IFR approaches, IFR departures and ground movements at a number of German commercial airports, including among others:
- Berlin-Brandenburg
- Düsseldorf
- Frankfurt
- Hamburg
- Hanover
- Cologne/Bonn
- Leipzig/Halle
- Munich
- Stuttgart
- Bremen
- Nuremberg
- Münster/Osnabrück
- Erfurt
- Dresden
- Saarbrücken
These seats have ILS systems of different categories and are able to handle IFR traffic even under low visibility conditions. DFS ensures that at every aerodrome Standardised decision-making procedures are available to convert the business to LVP at an early stage.
Categories of precision approaches and their significance
The announcement differentiates between different CAT-I, CAT-II and CAT-III approaches, which may be carried out depending on the available runway visual range (RVR) and the decision minima. Simplified applies:
- CAT I under normal IMC conditions with comparatively high minima
- CAT II with severely restricted vision with reduced minima
- CAT III in subcategories (IIIa, IIIb, IIIc) for extremely low or no visibility conditions
For CAT IIIc operation without a visible reference is theoretically possible, including automatic landing and taxiing. In practice, in Germany mainly CAT IIIa and IIIb as rolling completely without visibility is currently only permitted in test environments.
Low Visibility Procedures (LVP) and their activation
A central role is played by the Initiation of low-visibility procedures (LVP). They are activated as soon as:
- the specified RVR thresholds are undercut
- Weather forecasts announce significant deterioration in visibility
- shelters must be set up for ILS signals
DFS defines a clear procedure for this:
- Pre-warning phase - Recognising the conditions and informing the ground organisations
- Initiation phase - Activation of LVP and establishment of protected areas
- Operating phase - Execution of IFR approaches under LVP
- Cancellation phase - Return to normal operation after weather insight
It is important for pilots that certain operating restrictions apply during LVP, for example when moving vehicles, taxiing over critical zones or using taxiways in the immediate vicinity of the ILS localiser or glide paths.
Protecting ILS signals: why this is so important
ILS signals are sensitive to interference from Reflections or signal shadowing, which can be caused by, among other things
- Incorrectly positioned vehicles
- Aircraft on critical taxiways
- Construction or clearing vehicles
- Icy surfaces with a reflective effect
For this reason, there will be a so-called ILS protection area in which only controlled movements are permitted. This prevents incorrect information for autoland systems and flight directors and is particularly essential for CAT II/III approaches.
Significance for IFR pilots and general aviation
Several points are relevant for IFR pilots in general aviation:
- CAT II/III approaches require special equipment and approvals
- Charter, business and ambulance flights benefit of stable operating processes in bad weather
- Flight schools with IFR training receive realistic training conditions
- GA aircraft not equipped can often only be moved to a limited extent in LVP operation
In practice, this means that modern avionics packages - especially for turboprops and business jets - now rely more heavily on LPV and CAT-capable systems to increase availability in bad weather.
Future trends: digital rolling traffic and enhanced vision
Another trend that is becoming increasingly visible in the context of the LVP debate is that of
- LED roller guide lighting
- Ground Surveillance Systems
- Head-Up Displays (HUD)
- Enhanced Vision Systems (EVS)
- Synthetic vision on primary displays
These technologies reduce dependence on purely visual flight on the ground and increase safety in low visibility - a topic that is being strongly promoted internationally by ICAO and EASA.
Conclusion
With the updated procedures, DFS is creating a clear, stable framework for IFR operations in low visibility and at the same time strengthening the protection of sensitive ILS signals. This offers a high degree of operational safety for commercial flights, while general aviation benefits above all from standardised procedures and better planning. The demanding standards show that Germany is technically well positioned in the area of low-visibility operations and operates internationally comparable systems on an equal footing.
Source references:
NFL (the link requires a subscription to Eisenschmidt)
