In the late 1950s, during the Swiss AF's evaluation of a possible new high-performance aircraft to be purchased, a USN Grumman F11F-1 Tiger was flown by SAF test pilots.
In fact the aircraft under assessment was the F11F-1F Supertiger, but the Tiger was flown and evaluated for radar and armament performance, because the two Supertiger prototypes did not have them installed.
In the photos taken at the time of the F11F-1 flights, Maj. Moll was wearing a USN APH-5 helmet.
Until the appearance of the APH-5, USN crew were equipped with a mixture of H-4s and H-3s having H-4 liners. Meanwhile, work in helmet development continued with the MSA-N2 design, an immediate predecessor of the APH-5, being manufactured in very limited quantity. Another contract initiated work on an individually fitted helmet, designated BBC. A further development, the BBC-X2, a joint effort of the Navy and Air Force.
Initially, the APH-5 was designed without a visor, and the incorporation of a visor required a cover plate in order that the helmet shell itself would not be weakened by the visor guide slot. The final version was field tested for nearly a year by squadron pilots, during which time some 50 helmets had an average of 300 flight hours logged.
From the comments thus obtained, several modifications were made and the helmet was put into production.The APH-5 comes in two shell sizes, large and medium, which quickly proved somewhat inadequate for broad span heads.This deficiency was overcome by providing a thinner plastic earphone housing and by furnishing extension shim fittings which "close-cropped" pilots may insert as required.
The APH-5 protective capability was accomplished with an improved shell (H-3/4 ridges were removed to prevent localizing of impact forces) and by an inner layer of polystyrene plastic energy absorption material. Six sponge rubber pads were furnished with each helmet to provide individual fitting. Unforunately from the beginning the APH-5 was suffering from heat built-up.
The close fitting sponge rubber lining produced more heat than the cross-strap webbing of the H-3 and H-4. The sponge rubber also collected perspiration in an unsatisfactory manner. Improved, leather-covered liner pads were therefore introduced.