British Mk3E Aircrew Flying Helmet

The Mk3E helmet is simialr to the Mk3C, but only has one single tinted visor mounted on the inboard arms of the double visor mechanism of the Mk3C, meaning it can be locked down. It's application is limited to special role high altitude aircraft.

The reason for the single visor was that at high altitudes, sun glare reflections became an issue with two visors.

RAF/RN AP Resources

AP3456E, Part 1, Section 2 chapter 2, Figure 26 (AL 9, January 1982)

This is the only image I can find of a Mk3E helmet.

British Mk3E Flying Helmet

AP3456E, Part 1, Section 2 chapter 2, Paragraph 132 (AL 9, January 1982)

Quote:

Single visor using suspension system from the double visor mechanism (Mk3E helmets). For those aircraft which fly routinely at high altitudes where internal reflections between two visors are extremely troublesome and bird strike protection is not required the inner clear visor can be dispensed with. In the Mk3E helmet the tinted antiglare visor is mounted on the inner pair of hinges. This visor can be locked in the down position.