In writing
In writing means unless otherwise specified, the written expression of any actions related to this part, rendered in paper or digital format, and delivered in person; via facsimile, commercial delivery, U.S. Mail; or electronically.
Source
49 CFR § 109.1
Scoping language
For purposes of this part, all terms defined in 49 U.S.C. 5102 are used in their statutory meaning. Other terms used in this part are defined as follows: