Air Surveillance Missions

The North Sea air surveillance programme was launched in 1990 by the then Management Unit of the North Sea Mathematical Model, the MUMM, in cooperation with the Ministry of Defence. The MUMM equipped a military reconnaissance aircraft, a Britten Norman Islander, with special sensors. The Defence Ministry supplied the aircraft and pilot. Although the aircraft was transferred from Defence to Scientific Policy in 2005, the Defence Ministry continues to provide the pilot and effective cooperation between the Scientific Policy and Defence Ministries remains guaranteed.

Operational sea pollution

Since 1990 the principal mission has been the detection of marine pollution from the air in accordance with the international discharge standards of the MARPOL 73/78 Convention. Pollution by oil or other harmful fluids, originating almost exclusively in ships on the Belgian coast, is detected by means of special sensors aboard the surveillance aircraft, such as SLAR and IR sensors. These pollution control flights take place throughout the year, day and night, during the week and at weekends.

Belgium is not alone in this respect. These pollution control flights were launched in the framework of the Bonn Agreement under the terms of which all North Sea countries signalled a joint undertaking in 1989 to begin air surveillance of their waters with the aim of ending illegal discharges from shipping vessels, which had an unacceptably severe impact on the marine environment. The continuous presence of these surveillance flights over the North Sea is a major deterrent to potential sea polluters. Although the chances of catching a polluter in the act are small, any vessel that violates the regulations now risks heavy fines ranging from several hundred thousand to more than a million euros.

In recent years the aircraft has been used with increasing frequency to verify satellite detections of suspected oil pollution in our marine areas reported to Belgium via the CleanSeaNet service run by the European Maritime Safety Agency (EMSA). The oil pollution satellite surveillance uses exactly the same radar technology (SAR or Synthetic Aperture Radar) as the aircraft (SLAR). Reported satellite detections are systematically assessed by trained MUMM personnel.

SLAR operational discharge detection
A black 'vein', a zone without radar echo, indicates the probable presence of a discharge of oil from a vessel.

International missions

Although the observation aircraft principally carries out surveillance over Belgian marine areas and neighbouring waters, it also takes part in annual international surveillance operations under the Bonn Agreement. The North Sea countries work together regularly to carry out intensive surveillance flights over several days to check for illegal discharges (so-called CEPCO operations) in a specific sea area with heavy shipping traffic. Another example of international cooperation is the annual “Tour d’Horizon” operation in which the drilling platforms in the central North Sea area are checked by each country in turn, Belgium included.


Accidental sea pollution

A crucial double role is reserved for the observation aircraft whenever there is an accident at sea resulting in an accidental release of oil or other harmful substances, i.e. monitoring from the air and providing air support for the intervention teams fighting the pollution.

Flinterstar accident
SLAR result during the Flinterstar incident.

In the event of an accident at sea the observation aircraft monitors the incident from the air and is able to make a rapid evaluation of the extent of any accidental sea pollution, the threat this poses to the marine environment and coastal area, and the degree to which this can be fought. As soon as the observation aircraft has made an appraisal of the pollution at sea, it notifies the Coastguard Office which in turn notifies the competent services or an activated crisis committee on shore. The information obtained through air monitoring also serves as an input for mathematical models, which calculate the short-term drift of the slick. The combination of air surveillance and model simulations permits a rapid appraisal and effective evaluation of any accidental pollution and serves as a basis for determining the scale of the pollution fighting operations.

The aircraft is also available to the vessels fighting the pollution at sea: without air support it is virtually impossible for these vessels to obtain an overall view of an oil pollution incident and in most cases they are unable to rapidly locate the thickest areas of the oil slick where the action must be concentrated.

This dual service provision in an emergency at sea, as witnessed recently at the time of the Flinterstar incident in 2015-2016, is highly valued by the various authorities responsible for managing shipping accidents, especially in the framework of the General Intervention and Emergency Plan (GEI) North Sea.

Flinterstar accident
The Flinterstar incident.

To ensure a permanent state of readiness in case of emergencies at sea, the aircraft participates in one or more international pollution fighting operations a year. During these fighting exercises (POLEX exercises) the aircraft evaluates an experimental slick (usually an oil simulant) from the air and trains in accompanying the pollution fighting vessels of Belgium, neighbouring countries and other North Sea countries of Europe.



Fishery control flights

Since 1993 an important secondary mission of the observation aircraft has been to carry out fishery control flights for the Fishery Inspection Service of the Flemish Region. The Fishery Inspection Service uses the aircraft and resources placed at its disposal by the MUMM (location and communication systems, images, etc.) to exercise systematic control of fishing activities from the air, day and night. In particular these surveillance flights ensure that fishing vessels respect the access limits in shallow coastal waters (3 nautical mile limit) and territorial waters (12 nautical mile limit). If a vessel enters an unauthorised area the case is documented and the on-board fishery inspector draws up a violation notification. Fortunately, the number of fishing violations has decreased sharply over the years, due in part to the deterrent effect of the surveillance aircraft.

The aircraft also carries out regular international fishery control flights for the Fishery Inspection Service. This permits operations outside the Belgian marine area, enabling the Belgian fishery inspectors to check fishing vessels in the fishing grounds of neighbouring countries.

fishing vessel


Marine environmental management

To help protect the marine environment and ensure sustainable management of the marine areas the aircraft also checks activities requiring a permit: aerial surveillance of wind farms, monitoring of construction and operating activities from the air, checks to ensure compliance with the conditions of environmental permits, aerial surveillance of fish farming activities, experimental or other special fishing zones, and supervision of sports fishing to help enforce the protection of marine mammal species.

The aircraft is also used for the surveillance of sand and gravel extraction at sea. Concessions for extracting sand and gravel from Belgian marine areas are granted to private companies by the Federal Ministry of Economic Affairs. All licensed extraction vessels are equipped with a system to automatically record the date, time, position, speed, pump status, etc. The Ministry charges MUMM-OD Nature with the technical management and control of these black box systems. By reporting the observed sand and gravel extraction activities the aircraft provides useful information to verify the black box data.

The aircraft also monitors activities and respect for the regulations in protected marine areas such as special protection areas for birds (Birds Directive Areas), special areas for conservation of the natural habitat ( Habitats Directive and Ramsar areas) and marine reserves (Baai van Heist).

ZAGRI marine sand and gravel extractions


Belgian Coastguard

In the framework of the cooperation between the government services responsible for maritime activities in the Belgian Coastguard structure, the surveillance aircraft also contributes to the maintenance of maritime safety at sea in a more general way. The MUMM air operators report regularly any navigation violations at sea (vessels that stray into shipping lanes) to the Coastguard Central Office, check sea areas that are surrounded by a 500 m safety perimeter, such as the area around wind farms that no ordinary aircraft may enter, and report suspected violations of the regulations on aircraft Automatic Identification Systems (AIS). Suspect movements of vessels at sea, such as in border areas or anchoring areas in the North Sea, are also reported to the Coastguard authorities.

The aircraft takes part in annual joint operations at sea. These Coastguard operations (OPERA) are organised by the Maritime Security Centre (MIK) and permit the coordination of every means available during an intensive operation at sea over several days. The aircraft supports the maritime patrol units.

In the framework of the Coastguard cooperation the surveillance aircraft can also take part in rescue operations in the North Sea, for the Maritime Rescue and Coordination Centre (MRCC Ostend). The aircraft can, for example, participate in a search for persons missing at sea, providing extra support for the helicopters of the Air Force base at Koksijde and the MRCC.

The aircraft also reports to the Coastguard any notable drifting objects or lost cargo which might pose a risk at sea.


Scientific observation

The aircraft also carries out regular scientific missions. Seasonal marine mammal monitoring is carried out as part of the study of the environmental effects of the wind farms. Marine animal counts from the air are an ideal method for determining population densities in Belgian marine areas.


The aircraft is also used for aerial observation of the proliferation of algae, such as the spring bloom of phytoplankton (Phaeocystis sp.), the natural summer bloom of sea sparkle (Noctiluca sp.; microscopically small flagellates), or jellyfish concentrations. This provides useful information for the management of our North Sea and for scientific research and ecosystem modelling.

When air operators note conspicuous natural phenomena at sea, such as whales, marine fronts, floating masses of micro-algae, visible turbidity plumes, or groups of wintering seabirds, these are always reported.

plankton Noctiluca

Belgian surveillance aircraft

plankton Noctiluca