M43
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During the mid '80 - early 90's, Swiss AF evaluated a number of Chemical/ Biological Warfare (CBW) pilot protective systems.
The main evaluation criteria the chem/bio protection effectiveness and the compatibility/ integration with Swiss AF aircrew and aircraft operations.
Among the systems taken into consideration were Swiss Huber+ Suhner SM-90 protection mask, British AR-5 and CLARE (at the time under development); US made MC-2/P, M43, MBU-13/P and PIHM (Protective Integrated Hood Mask) / TAERS (Tactical Air Eye Respiratory System).
As usual, implementation of a number of equipment and aircraft modifications were foreseen, such as replacing breathing regulator and ejection seat hoses with "chemically hardened" ones and replace the NBC hood original ones with Swiss made filter canisters.
Here a M43 (Type 1) chem-bio mask.
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Developed for the AH-64 “Apache” attack helicopter, the M43 mask was compatible with its Integrated Helmet and Display Sighting System (IHDSS).
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In fact, the SAF was not evaluating the AH-64, it is not known why the M43 entered the list of tested equipment. It was planned to conduct assessments with third-generation NVGs, of which specific tests were under way. Nevertheless, there were not enough NVG units, so the tests with the M43 could not be carried out.
The M43 consists of:
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An integral hood made of bromobutyl and natural rubber provided with a drink tube assembly, secured on the wearer head by a skull-type suspension system;
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A face piece with lenses fitted close to the eyes; the lenses design based on the need for little-to-no visual impairment, positioned as close as possible to the eyes and optically adjusted to the wearer. This configuration increase visual capability to within 4% of non-masked vision.
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An air distribution assembly, which adjusts the flow of air to the oronasal cavity and hood;
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A pressure compensated exhalation valve assembly, which maintain overpressure in the mask/hood;
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A dynamic microphone, which interface with the helicopter communications systems.
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The mask is connected to two C2A1 filter canisters, which lower breathing resistance and (not shown here) a portable motor/blower filter assembly which operate on either battery or aircraft power.
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There were two M43 models:
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Type I one has a notch in the right eyepiece that accommodates IHDSS sighting device and uses an M-171/ AIC microphone for communication;
Type II has two spherical lenses and uses a dynamic microphone.
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During the Swiss tests, the masks were modified with the installation of an M-101/AIC microphone and CX-4707 comm cable.
Two control levers regulate the airflow to the cooling duct and the lens defogging system.
The outlet valve cover houses the outlet valve control (adjusted by the lower small lever) which controls the flow of air out of thre facepiece assembly.
Two control levers regulate the airflow to the cooling duct and the lens defogging system.
Sized, adjust the lenses for proper optical centering.
The RH lens has a notch shaped for the use of the helmet's IHDSS Helmet Display Unit (HDU).
With filters installed.
Sized, adjust the lenses for proper optical centering.