Guy Mitaux-Marouard getting ready onboard the Mirage Milan during the tests carried out in Switzerland in 1972.
GUENEAU 312/82 and 313/29
In 1968 the Swiss Air Force approached Dassault with a request to develop a new version of the Mirage as a ground attack aircraft capable of increased agility at low level in valleys. The SAF also wanted something with a lower landing speed for use on short, rough field sites.
Together, Dassault and the Swiss Federal Aircraft Factory (the Fabrique Fédérale d’Avions – FFA) developed a Mirage modified nose design, fitted with a pair of forward retracting fore airfoils – rapidly dubbed as “moustaches” – which would modify the aerodynamics of the aircraft and allow for the improvements required.
The prototype, named "Milan" (a bird of prey, in english "Kite", nothing to do with the italian city...) , made its first flight in Melun-Villaroche on May 29, 1970, piloted by Dassault test pilot Guy Mitaux-Maurouard.
In May 1972 testing began by the Swiss AF to assess if the Milan would satisfy the requirements. In competition was the American LTV A-7 Corsair II. Both aircraft apparently performed well,neither demonstrating a substantial performance advantage over the other.
On September 9, 1972, the Federal Council made the so-called "Nullentscheid" (zero/no decision), meaning that neither the Corsair nor the Milan were acquired. Instead, Switzerland procured two series of 30 used Hawker Hunter aircraft, a plane that was no longer up to date at the time. This "zero decision" was the object of heavy political controversy.
In film and pictures from the period, during the Milan demonstration flights, Dassault test pilot Guy Mitaux-Marouard is seen wearing a distinctive Gueneau helmet; the A-7 pilot wearing a Toptex.
The helmet worn by GMM was most likely a R&D hybrid based on the Gueneau 312/29, a derivative of the 313/29.
Certified in the early 1970s, the 313/29 was a modernised version of the Gueneau 313, intended for use on helicopter and training aircraft. Mainly used by the Belgian Air Force, it was worn by trainee pilots flying the SIAI Marchetti SF 260 propeller-driven aircraft; fitted with brackets on both sides allowing the left or right installation of a boom microphone, it could be equipped with a anti glare visor secured by an elastic band or with a pair of protective goggles.
It was fitted with "pull the dot" provided leather flaps for the use of an oxygen mask if required. Its headsling was secured to the shell by means of a nylon cord, as in the US P-series helmets.
With the option of an external 541- series visor fitted, the helmet was designated as 312/29.
Apart from the Belgian version, its use with or without visor was very limited. In France, they were utilized on a trial base only by the CEV/ CEAM (Centre d’Essais en Vol/ Centre d'Expériences Aériennes Militaires) and in Dassault’s Flight Test Department.
It is worth noting that the shell's leather edgeroll commonly used up until then was dismissed in favour of a (black or white) plastic one, which was certainly less problematic in terms of strength and durability – the same kind that would be used on future Gueneau helmets.
The shell that GMM used on the Milan in 1972 was a similar one and featured the holes for the headsling cord; however, the cord is not present and some holes were plugged with rivets designed to secure the headset suspension cords, as seen on the 312/82.
In the definitive version of the 312/82, apart from the aforementioned holes/rivets, the other holes were no longer present.
The helmet still had fitted the leather flaps for the oxygen mask; in the 312/82 version, bayonets were introduced in order to secure an Ulmer 82 oxygen mask in place of the Ulmer A-13/MS22001 seen in the footage.
The comm headset suspension system, which in the 313/29 and 312/29 versions used Velcro patches, was, as mentioned above, implemented in this prototype using cords.
The headsets could be adjusted using padded spacers. It is interesting to note that on the helmet used during the tests, the original positioning of the eyelets through which the cords passed had been modified; the position of both lower and upper ones were moved forwards by drilling supplemental holes – the same configuration later found on the 312/82.
The most helmet's striking feature is the modification of the 541 visor mount, whereby a metal plate was installed in place of the standard leather handle – most likely intended to prevent the ejection seat’s initiator handle from becoming jammed. This configuration subsequently probably inspired similar setups (such as the visor covers on the DH-151 and HGU-55 helmets for the Swiss AF Mirage III ).
Details of the two oxygen mask attachment configurations: the leather flaps on the 313/29 and the bayonet fittings on the 312/82 . Note the pin that limits the rotation of the fitting.
We do not know what type of communication harness was fitted to the GMM helmet, as there are no pictures to the best of our knowledge showing its left side; however, we can assume a configuration similar to that of the 313/29. In the 312/82 version, the connection is made via a LEMO connector.
Gueneau 313/29.
Gueneau 312/82.