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  fitted with a "Bungee visor".

 
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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 batch 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. 

 
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A standard DH-151, as it provided to F-5 E Tiger II pilots.

 

DH-151 BAMF-1 "MIRAGE III S and RS (AMIR) " 

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The DH-151 was the standard equipment 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. 

 
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As one of the possibly first DH-151 ordered, 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.

 
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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.

 
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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;

By swapping the Gueneau modified visors with the bungee 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.