Found a reference provided by a current WSP office in the "Ask A Leo" section of PNWRiders.com and have included it. Full link: pnwriders.com/law-enforcement/167976-
helmet-cameras.html
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The Washington RCW's (Revised Code of Washington) for helmet laws has the following excerpt -
(3) For purposes of this section, "motorcycle helmet" means a protective covering for the head consisting of a hard outer shell, padding adjacent to and inside the outer shell, and a neck or chin strap type retention system, with the manufacturer's certification applied in accordance with 49 C.F.R. Sec. 571.218 indicating that the motorcycle helmet meets standards established by the United States department of transportation.
When you look up the Federal Regulations for helmets, that describes the restrictions of the helmets. That is the law that restricts attachments to the helmets. Here is the post from the CFR's -
S5.5 Projections: A helmet shall not have any rigid projections inside its shell. Rigid projections outside any helmet's shell shall be limited to those required for operation of essential accessories, and shall not protrude more than 0.20 inch (5 mm).
So what is essential? Well, a camera such as a go pro, contour, or any other camera is not an essential item. As for the chatterbox and other communication devices, I think they fall under the following -
RCW 46.37.480 - Television viewers — Earphones - (3) This section does not apply to authorized emergency vehicles, motorcyclists wearing a helmet with built-in headsets or earphones as approved by the Washington state patrol, or motorists using hands-free, wireless communications systems, as approved by the equipment section of the Washington state patrol.
Are the chatterbox headsets approved by the state patrol? Not that I know of, but my interpretation is that it is a hands free device. As most things, it will come down to the officers discretion. If you are cited for the camera attached to the helmet, it will be for the Washington RCW 46.37.530 which references the Federal Regulation.
Here are the links -
Washington RCW's
Helmet Law -
https://apps.leg.wa.gov/rcw/default.aspx?cite=46.37.530
Earphones -
https://apps.leg.wa.gov/rcw/default.aspx?cite=46.37.480
Federal Regulation -
https://www.bikersrights.com/nhtsa/fmvss218.html (Look at section S5.5 Projections)
I hope this answers your questions.