Main source for service related information: USAARL Report No. 91-11 'SPH-4 Aircrew Helmet Impact Protection Improvements 1970-1990' by Ronald W. Palmer, Biodynamics Research Division, United States Army Aeromedical Research Laboratory, February 1991

The US Army introduced their first flying helmet, the APH-5A or APH-5 Quartermaster helmet, from around 1959. It was an adapted version of the US Navy Aircrew Protective Helmet no. 5 (APH-5). The change was mainly in the communications system as the US Army used the same impedance standard as the US Air Force. With the introduction of the APH-5A the number of head injuries incurred during US Army aircraft accidents was reduced by half compared to the number of head injuries incurred before helmets were used.
The early examples of the APH-5A had the same thick foam rubber edge roll as the US Navy APH-5 and usually came in white colour. Later examples had thin black rubber edge beading and usually came in olive drab colour. A ballistic version, the Antifragmentation Flight Helmet No. 1 (AFH-1), was introduced in the late 1960s (NSN assigned 18 December 1967).
The US Army was not satisfied with the APH-5A and the AFH-1 because their noise attenuation and retention capabilities were too poor. Therefore they were replaced by the Sound Protective Helmet No. 4 (SPH-4) from 1970.

Early APH-5 Quartermaster helmet made by Gentex in July 1961. It has the same thick foamrubber edgeroll as the
US Navy APH-5. The visor housing is made of glassfibre with metal edges along the visor lock knob track. The
headset is an H-75C/AIC, the latest version of the H-75 series also used in USAF P-4 and P-4A helmets. The micro-
phone is an M-33/AIC or M-33A/AIC banana boom mike. This helmet was white originally but was painted olive drab
as a field modification. © Unknown

White APH-5A helmet manufactured by Sierra Engineering with their typical six-lobe visor lock knob. This helmet is fitted with Hardman receivers to enable it being used with the MS22001 oxygen mask shown in the pictures. It was used for flight testing the US Army Grumman OV-1C Mohawk aircraft. The picture to the far right shows the period round helmet bag. Pictures © bill_in_nj

Early APH-5A helmet as evidenced by the thick foamrubber edgeroll. This helmet has been modified with a Sierra
one-piece ramshorn dual visor. Sierra advertised these visors for the APH-5A helmets in their 1965, 1969 and 1973
catalogues but it is quite rare to find a US Army helmet so modified but The Greek Air Force used this configuration
(see 'GREEK HELMETS' and 'APH-5A' in the menu to the left). Pictures © mid_60s

Later Sierra Engineering APH-5A helmet with its thin black rubber edge beading. It has a plastic visor housing with
integral edges on the visor lock knob track. Its shell is very much like the APH-6 shell and it also uses the early
APH-6 fitting pads. All pictures are thumbnails. © Bluelight