The Guardian medium-range maritime surveillance aircraft is appreciated both for its reliability and comfort.
In July 1971, the United States Coast Guard launched the HX-XX Medium Range Surveillance (MRS) programme to replace its Grumman HU-16E Albatross seaplane. The aircraft had to be capable of performing surveillance, search and rescue and environmental protection missions along the coastline and over maritime zones under its control.
With the Falcon 20 G, a version of the Falcon 20 F with Garrett ATF-3-6 turbofans in place of the original General Electric CF 700-2Ds, Dassault had a proposal capable of meeting the Coast Guard requirements.
The aircraft had been at the project stage since Dassault had developed the design in 1969. Certain adaptations were introduced in response to the Coast Guard requirements in terms of systems and instruments.
On 5 January 1977, William T. Coleman, US Secretary of Transportation in the administration of President Gerald Ford, signed a contract for 41 Falcon 20 Gs ($204 million) under the designation HU-25 A (serials 2101 to 2141).
Dassault Aviation had managed to penetrate the ultra-closed US market in spite of the Buy American Act.
Two prototypes were built simultaneously, one in the USA, the other in France. The first Falcon 20 G (n° 362), the first aircraft to be equipped with two ATF-3 turbofans, flew in Mérignac on 28 November 1977, with Hervé Leprince-Ringuet at the controls. A Falcon 20 F (n° 371), modified to test the equipment and systems requested by the Coast Guard but retaining the CF 700 engines, flew at Falcon Jet Corporation in Little Rock (Arkansas) on 4 August 1978.
The aircraft was certificated by the French DGAC airworthiness authorities on 21 June 1981. Deliveries took place from February 1982 to December 1983.
The medium-range maritime surveillance model derived from the Falcon 20 G was designated HU-25 A Guardian. A total of 41 aircraft were completed in Little Rock. Seven aircraft were fitted with the “Aireye” system, designed to perform scientific and maritime environmental protection missions, particularly locating and monitoring oil spills.
Two Guardians were successfully used during the Gulf war in 1991 from a base in Bahrain, to monitor the movement of oil slicks along the Kuwaiti and Saudi Arabian coasts. Their mission availability was the highest among all the allied aircraft engaged in the conflict.
Specially equipped Coast Guard HU-25 Bs and Cs were actively used for drug interdiction missions along the US coastline.
In 1998, 17 aircraft were still operational at bases in Cape Cod (Massachusetts), Miami (Florida), Corpus Christi (Texas) and Mobile (Alabama).
The Guardian was particularly reputed for its reliability and comfort.
In June 1977, the French Navy had to take account of its increased need for maritime surveillance equipment, following the progressive extension of the French economic exclusion zone up to 200 miles.
To perform its maritime patrol and maritime surveillance missions, replacing the Lockheed P-2H Neptunes which had reached the end of their service life in the 9 S and 12 S squadrons in the Pacific, the Naval Air Arm needed an aircraft capable of flying fast and changing altitude rapidly if the need arose.
For safety reasons, it had to be a twin-engine design, capable of rapidly reaching a distant location and of covering an extensive maritime zone in the minimum time, and fitted with reliable and robust high-performance navigation and detection systems. In view of the need to operate in hot and humid conditions, the Naval Air Arm also wanted an aircraft requiring little maintenance and straightforward flight preparation.
Building on its experience with the HU-25 A Guardian, Dassault proposed to the French Navy a light twin adapted to the maritime surveillance mission and meeting the above criteria.
The Gardian was equipped with a navigation and surveillance suite including a Varan radar, adapted to the detection of small objects in heavy sea states, a Crouzet navigation system to visualise the tactical and geographical situation, a computer and automatic navigation table. A hatch was provided to air-drop rescue equipment, markers and, if need be, personnel. It was fitted with two large observation windows and four under-wing hardpoints capable of carrying significant loads (various sensors, target towing and countermeasures).
The aircraft were designed for four types of mission:
The first Gardian, the navalized version of the Falcon 20 H, subsequently the Falcon 200, made its first flight at Mérignac on 24 April 1979, flown by Henry Suisse and Jean-Marie Barthelemy. Aircraft n° 48, the first aircraft of this type to come off the Bordeaux-Mérignac assembly line, made its first flight on 15 April 1981, under the control of Hervé Leprince-Ringuet (pilot) and Jean-Marie Barthelemy (test flight engineer). This pilot and the flight test team went on to conduct the final evaluation of the Gardian in collaboration with the CEV flight test centre.
On 13 May 1981, the French government, on behalf of the Navy, signed a contract covering development and production tooling for five Falcon Gardians in two batches of two and three aircraft, respectively. Aircraft n°48 was officially handed over on the same day.
In 1982 the aircraft performed demonstration tours for potential customers in the Middle East, India, Africa and Ireland.
On 14 April 1983, Gardian n° 1 was officially handed over to Admiral Leenhardt, the Navy Chief of Staff, by Benno-Claude Vallières.
Design studies were performed for a multi-role Gardian 2 version capable of performing five additional missions: