721 Squadron – Danish transport squadron

721 Squadron – The Challenger flight

Maritime patrol, VIP flights, and heavy transport applications are just some of the tasks that 721 Squadron handles.
In this article we look at the Challenger flight, and especially its main task of maritime patrol.
721 Squadron
In the Royal Danish Air Force (RDAF), the job of air transport is handled by 721 Squadron, located at Aalborg Air Base in the northern part of Jutland. The base is also known as the Air Transport Wing Aalborg.

The squadron currently has a total of eight aircraft, divided into two types. To handle the heavy long-range transport missions, the squadron flies four Lockheed C-130J-30 Hercules aircraft. For smaller transports, VIP flights and maritime patrol missions, there are four Canadair CL-604 Challenger aircraft.

In this article we look at the Challenger flight and especially its main task of maritime patrol.

CL-604 Challenger aircraft
The RDAF received three Canadair CL-604 Challenger aircraft (C-080, C-168 and C-172) between 1998 and 2001. These aircraft replaced the Gulfstream III which the RDAF operated from 1982 until 2004. The Challenger was originally built as a civilian medium-range aeroplane, but the RDAF version is equipped with a lot of additional military-style equipment such radar and a comprehensive communications suite.

In addition to this, there is also the more specialized equipment used for the maritime patrol missions. The Challengers are typically flown in one of two configurations; either as a VIP transport aircraft or as a maritime patrol aircraft. In its role as a VIP transport aircraft, it carries members of the royal family, high ranking military officers and top government ministers around the world. In this configuration the aircraft cabin is equipped with comfortable leather seats.

For the maritime patrol mission, the cabin is less luxuriously equipped with two large consoles that are operated by system specialists.

The motto of the squadron shield “Ubicumque Qandocumque”, which means
“Anywhere – Anytime”.
Ready to go. The ground crew delivers the plane to the crew.

Pirate Hunting in Africa
721 Squadron’s Challenger aircraft have on several occasions participated in Operation Ocean Shield, the NATO led mission around the Horn of Africa. The purpose of Operation Ocean Shield is to hunt for the pirates operating in the region and to make it safer for merchant ships to sail through the area.

In the autumn of 2013, RDAF Challenger C-168 was deployed as part of Operation Ocean Shield. During a mission on 7 October, the aircraft suffered an engine failure shortly after take-off. The aircraft was able to return to base safely, but the engine could not be repaired on site and it was therefore necessary to send a new engine so the Challenger could resume its participation in operations.

Because the RDAF did not stock any extra engines for the Challenger, it was necessary to take an engine from one of the two aircraft that had remained at Aalborg Air Base. An engine was taken from C-080 and sent to the Seychelles, from where the Danish Challenger aircraft were operating. This meant that there was now only one Challenger left in Denmark and that had to handle all the tasks normally undertaken by three planes. This quickly proved impossible and therefore the RDAF started to explore the possibility of buying a few spare engines.

As it turned out, it was actually lower cost to buy a complete used aircraft for the same price as two new engines and as such it decided to purchase a fourth Challenger aircraft and put an engine from the new plane onto C-080 so that there again were two operational aircraft in Denmark. In February 2014, the damaged engine came back from repair and eventually C-168 and C-080 got their own engines back.

The newly purchased second-hand aircraft was integrated into the 721 Squadron inventory to relieve the other planes as necessary. It was also decided to keep it in a permanent VIP configuration so that the ground crew wouldn’t have to spend hours reconfiguring the aircraft between the VIP configuration and the maritime patrol mission sorties. The new aircraft was assigned the serial number C-215 and on the 6 June 2014, it was officially handed over to the RDAF.

Maritime Patrol
With just over 4500 miles (7300 km) of coastline and several busy international shipping lanes going through its waters, maritime patrol and surveillance is of great importance to Denmark and obviously, it is 721 Squadron’s primary mission.

In order to comply with international treaties, at least two maritime patrol missions have to be flown every week. These missions typically follow one of a number of predetermined routes which cover the inner Danish waters, the western part of the Baltic Sea and the North Sea out towards the Danish oilrigs. The main issue that the Challenger crew are on the lookout for on these missions are ships dumping oil, as this is not only illegal, but also poses a major environmental risk for the Danish coastline and marine wildlife.

On a maritime patrol mission, there are a total of five crewmembers on board the Challenger, namely the mission commander, the first officer, a flight Engineer and two system operators.

The mission commander has the overall responsibility for the planning, briefing and execution of the mission. The first officer’s job is to assist the mission commander in the cockpit during the mission. This can both be in terms of handling radio calls during the flight and also with flying the aircraft.

The flight engineer has a lot of different jobs to undertake during a mission. During take-off and landing, the flight engineer sits on a jump seat between the two pilots, where he assists with various tasks whereas during the flight, he is an extra set of eyes when an area needs to be searched visually. He is also trained to drop different pieces of kit from the Challenger, such as life rafts, markers or flares.

Speaking of which, the Challenger carries two types of markers; one with dye and one with coloured smoke. Flares are used during night missions and typically fired out at around 10,000 feet and where they will then slowly descend under a parachute. This gives the Challenger approximately five minutes to make a visual search of the illuminated area. Drops from the Challenger are made through the cargo door which is located just below the left engine. During VIP missions, the flight engineer acts as steward and waits upon the VIPs.
“The SLAR is the Challengers primary weapon in locating ships that are dumping oil.”
Visual scanning
The two system operators sit in front of their consoles in the main cabin. The left console is used to display data from the Side Looking Airborne Radar (SLAR) located under the belly of the plane. The SLAR is a SLAR 9000 and is produced by the Danish company Terma.

The SLAR is the Challengers primary weapon in locating ships that are dumping oil. The radar works by measuring the ripples on the water surface.

If there is oil present, there will not be the usual ripples on the water and this lack of motion will be picked up by the SLAR. These areas of oil pollution on the water’s surface show up as black patches on the radar screen. Besides monitoring the image from the SLAR, the system operator on the left console also has an electronic map showing the area they are currently flying over. This map shows all the commercial ships that are equipped with a transponder. Using this map, the system operator can, with a single click, see the name, speed, direction plus other information about the ship.

The system operator seated by the right hand console is in charge of most of the radio communication with ships and air traffic controllers in the regions along the route. He also controls the Forward Looking Infra-Red (FLIR) camera which is mounted in a retractable housing under the rear of the fuselage. Another of his tasks is to take photographs and video footage of any ship that is caught off-loading oil illegally.

Transferred to the police
Where a ship is suspected of dumping oil from the SLAR image, there is an established procedure for gathering the necessary evidence. First a screen capture of radar plot is made to show the exact location of the suspected ship. The Challenger then descends to low level and approaches the ship from the rear and makes a flyby, gathering further evidence in the form of photos and video footage.

After the flight has returned to Aalborg Air Base, the evidence that has been collected is transferred to the police, who are then responsible for handling the criminal charges against the ships owners.

Since the Challenger began flying maritime patrol missions around the Danish shores, the number of ships that dump oil in the area has decreased by approximately 80%.

When the Challenger aircraft are flying maritime patrol missions, it is possible that they can be contacted by Admiral Danfleet Headquarters and asked to assist in searching for people or ships lost at sea. This is a task the Challenger aircraft is very well suited for.

The two system operators held various positions during the flight,
but also complement each other if one is forced to leave his seat.
The system operator closest to the camera is responsible for radio communications,
and control of the FLIR camera, while the other monitors the image from the SLAR.
While on maritime patrols, it happens that the Admiral Danfleet Headquarters asks the Challenger aircraft to participate in the search for persons at sea. Here guides the Challenger one pilot boat to a man in a small boat, after he was found by the Challenger aircraft doing a SAR mission.

Search And Rescue
The search is done typically by a rapid descent to a lower altitude, typically 500-800 feet at a speed of about 200 knots, in the area where the missing person or ship is believed to be.

It then searches the area both visually and using the FLIR camera, flying a search pattern which is slowly expanded in the direction the missing persons or ship would have drifted with the wind and currents known to be in the area. This is a situation where the Challengers five man crew comes into good use. Everybody keeps a lookout for the missing persons and if needed, the flight engineer can drop a life raft and/or a marker in the vicinity of those in need.

When the missing persons are found, the aircraft descends to about 100 feet and make a fly-by to confirm that it is in fact the people they were looking for and to assess their situation. At the same time, the aircraft position is plotted and sent to the relevant authorities, who then dispatch either a rescue helicopter or rescue boat.

Intercept target for AVB
The RDAF maintains a Quick Reaction Alert (QRA) force, consisting of two F-16 Fighting Falcons at Skrydstrup Air Base in the southern part of Jutland. Their main task is to intercept and identify unknown aircraft approaching Danish airspace. The QRA force typically fly one training mission a day and if it takes place while a Challenger is on a maritime patrol mission in the area, the QRA jets will sometimes use the patrol aircraft to practice intercepts.

The Challenger aircraft are also used for maintaining Danish air sovereignty. This is because 721 Squadron is the only RDAF squadron who regularly fly over the northern parts of Greenland. Known as Air Group West, they operate from Kangerlussuaq/Søndre Strømfjord in Greenland. When flying the Challenger aircraft over Greenland, in addition to upholding the sovereignty, they also do maritime patrol missions, fishery inspection and drop equipment to the “Sirius Patrol”, the Danish Army’s special forces stationed in the northern part of Greenland.

It happens that the QRA planes uses the Challenger as “Interception-targets”.
Here are two F-16 Fighting Falcons in formation on the Challenge’s right wing.
The two system operators monitor the various systems aboard the Challenger.
Future of Esk. 721
With the new fourth Challenger aircraft in permanent VIP configuration, it will be easier for 721 squadron to meet the obligations which the RDAF has when it comes to the surveillance of Danish waters. It also makes the squadron less vulnerable if an aircraft must be taken out of service for longer periods of time, as happened with C-080 when C-168 lost one of its engines.

For the ground crew, this means that they will spend less time taking the marine patrol equipment in and out of the aircraft, which in turn will reduce the wear on both the equipment and the personnel.

FLYMAG would like to say a big thank you to HIF, GEA, FIR, KIM and Karl from 721 squadron, and Jesper Balle from the Air Transport Wing Aalborg, for their great help with this article.