The APH-6 series of helmets has been sadly neglected in discussions so far, which to me is strange since the APH-6 series was the standard US Navy fast mover helmet for almost two decades. This article seeks to remedy that situation but is in no way the final treatise on the topic. Having had very limited access to official documentation I have prepared it from military specifications and what you could term 'circumstantial evidence' - mainly Sierra and Gentex catalogues and observations from actual helmets and photos.

APH-6
The APH-6 helmet seems to have been issued in 1961, at least the first traceable APH-6 specification (MIL-H-22995(Wep)) dates from 27 July that year. APH-6 helmets from this era look very much like the APH-5. Its earphones are attached with a single screw through the helmet shell, it has large padded earpads and fitting pads, all covered in tan-coloured leather and a single visor housing with metal tracks, metal reinforced visor guides in the visor cover, and the visor lens itself has a guide tracks in each side. The styrene energy absorbing liner consists of three parts split longitudinally.
The only differences seem to be that the APH-6 has a thin rubber edge beading instead of the APH-5 neoprene edgeroll, and then of course the APH-6 has its special racheted oxygen mask receivers that take the so-called butterfly bayonets.

Early APH-6 helmet made by Sierra as revealed by the blue six-lobe visor lock knob. Click on the thumbnails to see
larger pictures. Left picture is copyright unknown, three pictures on the right ©Milehigh.

APH-6A and APH-6B
In the late 1960s the APH-6 helmet is issued in an improved single-visor version designated APH-6A and a double-visor version designated APH-6B. (Federal Stock Number for APH-6B size large assigned on 16 March 1968, size medium 13 April 1968). The main change in the APH-6A seems to be a new type of earphone installation method where the attachment screw is inserted through a plastic disc covering a larger hole in the helmet, thus allowing more freedom of movement for adjusting the earphones to individual pilots. Other changes include nylon visor tracks. The APH-6B has the same changes as the APH-6A but features a ramshorn double-visor. Helmets produced by Gentex have three-piece ramshorn visors and helmets produced by Sierra have one-piece ramshorn visors. It is noteworthy that the change from APH-6 to APH-6A and -B was not spurred by a specification change.

APH-6A helmet used by Lt.j.g. Kahle from VAW-11. The white earphone adjustment discs stand out clearly on the
orange background. The energy absorbing liner is still three-part and ear and fitting pads are tan. Click on the
thumbnails to see larger pictures. Copyright unknown.

APH-6B helmets showing dual-visor setup. Both helmets have oxygen masks with white hardshells used for nuclear
flash protection. Click on the thumbnails to see larger pictures. Three pictures to the left © Downwind28, picture on
the right ©Milehigh.


At first glance a fine APH-6C but a closer look reveals that this is in fact an APH-6A that has been modified with a
one-piece ramshorn dual visor and late type headphones. The three-part energy absorbing liner is a giveaway. The
visor modification is revealed by the holes in the energy absorbing liner where the visor housing screws went.
Usually the holes would have been plugged with styrene but not so in this case. A closer look at the edge beading
around the oxygen mask receivers also reveals that the helmet shell was repainted at some point. Pictures upper
row © eBay seller 'sgt.hulka'. Pictures lower row © Tomcat


APH-6A helmet modified with dual-visor, a special energy absorbing liner made of light blue foam, and a front pad
of the same type as used in HGU-2A/P and HGU-26/P helmets. Another group member has a single-visor APH-6A
with the same liner, and both helmets have the modification label shown in the upper righthand picture. 'NAS NORVA'
means Naval Air Station Norfolk Virginia which today is just called Naval Station Norfolk. This particular helmet was used by a guy flying S-2 Trackers. At least two other helmets have been identified with the same modification
including an APH-5. My theory is that the modification increased the noise attenuation of the helmet, making it easier
for anti-submarine warfare sonar operators to hear the signals from the sonobouys through the engine noise in the
S-2 Tracker and possibly also P2V Neptune rear compartment. Pictures © Tomcat

APH-6C and APH-6D
On 25 April 1969 the MIL-H-22995(Wep) specification is updated to MIL-H-22995A(AS).
As a result two new versions of the APH-6 series of helmet, the APH-6C and APH-6D are introduced, APH-6C being a double-visor version and APH-6D a single-visor version. The main changes introduced were a new two-part styrene energy absorbing liner, smaller earcups with plastic-covered earpads and smaller fitting pads. (Federal Stock Number for APH-6C size medium and large assigned on 1 May 1970, for APH-6D size large on 18 February 1972, and size medium on 2 March 1972)


APH-6C manufactured by Sierra Engineering, hence the one-piece ramshorn visor. Fitting pads are missing. Click on the thumbnails to see larger pictures. © Chad Le Beau


APH-6D helmets with single visor and retaped in VF-301 'Devil's Disciples' artwork. The label at the rear only says
APH-6 but with the reference to MIL-H-22995A (AS) and a 1976 order date there is no doubt that this is an APH-6D.
Click on the thumbnails to see larger pictures. © Tomcat

Custom fit APH-6s and other 'anomalies'
In the 1970s a number of US Navy pilots ordered custom fit APH-6 helmets from the company Protection Inc. on a private basis. Sierra Engineering also offered this service. All the Protection Inc. APH-6 helmets I have seen so far have cast aluminium oxygen mask receivers of the same type as seen on HGU-2A/P, HGU-33/P and many other helmets. There are a few examples of US Navy APH-6 helmets being custom fit in the field, retaining their ratchet oxygen mask receivers, but in at least one other country, Singapore, it was done consistently.
Other APH-6 configurations were made to the customer's specifications, one such example is seen below. It is equipped with a foam liner (most likely an HGU-17/P liner) and cast oxygen mask receivers. The communications setup is remeniscent of the APH-5A helmet but the label clearly identifies the helmet as an APH-6.

Four different custom fit APH-6 helmets. Squadron colours from left to right are VF-51, VF-213, Grumman test
pilot Pete Tummillo, and VMA-314. Click on the thumbnails to see larger pictures. From left to right pictures are
copyright Mirage, Milehigh, DocBoink, DocBoink, and Milehigh.

Custom fit APH-6C and APH-6D helmets in the colours of 143 Sqn, Republic of Singapore Air Force (RSAF). The
edgeroll is a Sierra/Scott snap-on edgeroll like the ones in widespread use with custom fit HGU-2A/P and HGU-26/P
but designed specifically for the APH-6 shell. Click on the thumbnails to see larger pictures. Pictures © Phoenix143

APH-6A made to Australian order for use in DHC Beaver aircraft on the Antartic. The configuration of this helmet is
so far removed from a standard APH-6A that only the label reveals what it is. Non-standard items include the
communications system, sand-coloured rubber edge beading, cast aluminium oxygen mask receivers, chin strap
with stud-and snap opening, and of course the HGU-17/P foam liner. Click on the thumbnails to see larger pictures.
Pictures © Howard Jones