THE SWISS DH-151
In order to to overcome the problems experienced with the Gueneau 316, during the mid '80 the Swiss AF decided to purchase a serie of Gentex Bauer/ Protection, Inc. DH-151.
DH-151 is a Gentex internal definition, "DH" means Designated or Design Helmet. Supposedly standardized as PRK-37/P, the DH-151 shell later became the base for most of the USN HGU's type helmets, afterwards, further trimmed, for the HGU-55/P.
According their uses and the technological evolution, the Swiss DH-151s underwent a noticeable configuration evolution. In their last version, a number of them are still in use today.
The Swiss AF complete helmet designation is DH-151 PA-594- followed by two main definitions : BAMF-1 and BAMF 2.
BAMF stands for "Bundesamt für Militärflugplätze" (Federal Agency for Military Airfields), which managed all aspects - technical and operational - of the Swiss AF.
BAMF-1 identifies a shell fitted with (modified or not) PRU-36 double visor assy; BAMF-2 one fitted with a "Bungee visor".
A DH-151 as it was delivered from Gentex Bauer: Padded black leather edgeroll,
PRU-36 double visor assy, cast oxygen receivers; everything in "Pearl White" livery;
a nape strap installed on request .
Internally, the helmet was fitted with a Custom fit polyurethane foam liner (PRU-39/P) molded on crewmember's head and "elephant's ear" earphone pads. In some cases, a V-TEC liner was installed.
Comm system : H-143/ AIC. After delivery, a "Swiss boom mike bracket" installed on the LH side of the shell.
A first serie of helmets were provided completely assembled, with the pilot's name stencilled on the rear side; the stencils applied before the final clear paint coating.
Later helmets, as the one picured, were assembled with spare (not named) shells.
Basically a standard DH-151, as it was provided to F-5 E Tiger II pilots.
DH-151 BAMF-1 "MIRAGE III S and RS (AMIR) "
The DH-151 was also provided to Mirage III pilots, nevertheless, because the upper initiating handle of the Mirage's Martin Baker Mk. 4 ejection seat could interfere with the standard double visor assy, a suitable locally designed and differently shaped visor cover replaced the standard PRU-36 ones. Mirage III S visor covers were left normally grey (not painted), Mirage III RS ones painted with the aircraft camo livery colors. same visor covers were installed also on later HGU-55s.
As one of the possibly first DH-151 odered, this helmet sports the pilot's name on its back.
The owner, also active test pilot in the GRD, (Gruppe für Rüstungsdienste - Armament Services Group) flew, among others, DH Vampires, Venoms, Hawker Hunters, Mirage III S/BS/RS, and various propeller aircrafts. He was active in the Squadrons 7, 9 and 17.
He probably painted himself the cover in white.
During the mid-1980s, the Swiss AF was testing the aircrafts that would replace the Mirage III. Among these the Northrop F-20, Mirage 2000, F-16 and the F/A-18 which would then be declared the evaluation winner.
A few years before a new pilot’s helmet concept, the HGU-55, entered service in the US Air Force, introducing new standards of weight, visibility and comfort.
Although an improvement compared to the Gueneau 316 that it had replaced, the DH-151 was still of "old" design and considered no longer compatible, especially in terms of weight, with the performance of new generation jets.
The H-5, after years of trustworthy service, due to ageing and lack of spares was in the process to be phased out. The AF launched a project to evaluate a new "light helmet" for the crews of the current and future AF aircrafts.
Various models and solutions were considered, finally the HGU-55/P was chosen as the future helmet of the Swiss AF.
However, before the end of the evaluations - most likely for economic reasons - a "local" and "ad interim" solution sought. Given the availability of spare parts, HGU-55 "lookalikes" were created with shells of grey painted DH-151 fitted with Gueneau 316 visors modified as “Bungee visor”.
A small quantity of this first version of the DH-151 "light" were still in service not long ago.
Following the delivery of the HGU-55, based on its configuration, some improvements of the DH-151 took place.
By replacing installed oxygen cast receivers with lightweight ones;
swapping the Gueneau modified visors with the ones of the HGU-55.
A number of these helmets are still in use today, in their grey livery or SOLAS taped.
Below, an F-5 F crew. The front cockpit pilot is equipped with a HGU-55, the rear one with a DH-151 BAMF-2.
Photo taken from the book “Swiss Tiger Parallel Flight" by Peter Lewis, Goatworks 2017, published by kind permission of the author.