GUENEAU ZEUS TYPE H2V MOD.
With the introduction of NVG systems on helicopters in the early 1990s the Swiss AF began to explore the possibility to upgrade/modify the SPH-4 in use at the time to the SPH-4B configuration. The objective was to improve the wearing comfort and stability of the helmet, hopefully resulting in less pilot fatigue.
Unfortunately, due to different reasons, the program took a substantial delay, and in the meantime other helmets which were compatible with NVG installation had appeared on the market.
All of them were tested. Eventually the SPH-4B was judged insufficient and the HGU-56 declared "nicht Truppentauglich" (not suitable for troop use).
The tests with the Guenau ZEUS (H2V “MOD”) continued, and again, other new models appeared on the market in the early 2000's. The ALPHA (Advanced Lightweight Protective Helmet for Aircrew) 200 made by Helmet Integrated System Ltd. and the MSA Gallet LH250. Both were added to the evaluation list.
At the end of the assessment, around 2005, the ALPHA 200 was selected as the new Swiss Air Force NVG-compatible helicopter helmet.