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Alpha 400 [Multi-Fit] Helmet

The Alpha 400 Rotary Wing Helmet System was a mufti-fit rotary wing passenger helmet system designed specifically for passengers, casual users, and when the helmet wss not a personal use item. It was available in two sizes: Medium and Large; and in a range of colours; gloss white, yellow, red and blue, suede blue/grey and suede olive/green.

Whilst the Alpha 400 has been discontinued, HSL still has limited stock available and are able to continue servicing and/or repairing the helmet. We also have hygiene parts available for the Alpha 400.




  • Two available sizes
  • Ensures an suitable fit for a variety of different head sizes.
  • Stable, comfortable helmet platform
  • The unique quick fit system, incorporating ratchet nape adjustment, ensures helmet stability is maintained throughout the flight.
  • Independent ear cup adjustment
  • The webbing mounted ear cup allows independent fitting of left and right ear positions, eliminates transmitted resonance and together with the shell mounted locking levers, maintains unsurpassed passive noise attenuation.
  • Communication setup
  • A wide range of equipment options is available for the cockpit set up, including straight and coiled communication cords, microphones, plugs, and connectors.
  • Visors
  • Dual visor options provide maximum eye protection and field of view. Independent left and right hand lock up/down lever operation. A choice of clear, smoked and amber options are available.
  • Rigid Visor Cover
  • Provides protection for the visors. The unique fitting and adjustment facility ensures correct eye relief is achieved.
  • Adjustable Features
  • Fore/aft tension
    Brow/crown comfort pads
    Ear capsule tension
    Chin strap tension
    Visor height
    Boom microphone
  • Customisable
  • Easy order guide enables you to tailor the Alpha 400 to your individual needs.


If you are still unsure, there is the option for visiting our facility in West Sussex and having your head measured by a qualified Alpha Helmet specialist, and also to try on the suggested size.

Head Measuring Instructions

1. For measurement [B] and [C] a head measuring calliper will be required. These are available from Headset Services Limited on request.

2. For measurements [B] and [C] ensure the callipers are pressed against the skull. Slide the callipers back and forth to locate the maximum measurement.


Both comfort and retention are key to selecting the correct size of helmet. Should a head size fit into two options, the smaller size of helmet should be selected wherever possible. If any of the measurements enter the range for the next largest helmet then that is the size that should be selected.

Ordering Options


Ordering an Alpha Helmet

We make the ordering process of an Alpha Helmet simple. With the help of the specially designed Easy Order Guides showcasing the various options. Our Sales Team are also available to help you make the right choice.


Easy Order Guide for Alpha 400 Helmet

Measuring Sheet for Alpha 400 Helmet

Colours and Textures

The Alpha Helmets are available in an array of different gloss and suede colours.

Hover the mouse pointer over the options below to see how they look.

Gloss White

Gloss Yellow

Gloss Blue

Gloss Red

Suede Blue/Grey

Suede Olive/Green


Optional Extras

HSL is able to offer you something a little extra. From its own Active Noise Reduction to a Bose A20 or David Clark ONE-X headset installed inside an Alpha Helmet. Alternatively, the CEP Interface Kit which offer extra hearing protection.

Find out more about:

Active Noise Reduction

NVG Lip Lights

CEP Interface Kit

Hygiene Parts

Deluxe Helmet Bag

Contact Us

Contact Form


Headset Services Limited
Unit 8, The Quoin Estate
73 Marlborough Road
Lancing Business Park
West Sussex
BN15 8AD
United Kingdom

Opening Hours

Monday: 08:30 - 17:00
Tuesday: 08:30 - 17:00
Wednesday: 08:30 - 17:00
Thursday: 08:30 - 17:00
Friday: 08:50 - 17:00
Saturday: Closed
Sunday: Closed


+44 (0)1273 234 181

Email Address

Let us help you make the right choice.