British Mk3D Aircrew Flying Helmet

Not much information exists on the Mk3D, but I did find this one little extract below.

RAF/RN AP Resources

AP3456E, Part 1, Section 2 chapter 2, Paragraph 133 (AL 9, January 1982)

Quote:

It incorporates attachments for passive night vision goggles and at present is only for use in rotary wing aircraft.