14 CFR § 135.79

Each certificate holder must have procedures established for locating each flight, for which an FAA flight plan is not filed, that—

Provide the certificate holder with at least the information required to be included in a VFR flight plan;

Provide for timely notification of an FAA facility or search and rescue facility, if an aircraft is overdue or missing; and

Provide the certificate holder with the location, date, and estimated time for reestablishing communications, if the flight will operate in an area where communications cannot be maintained.

Flight locating information shall be retained at the certificate holder's principal place of business, or at other places designated by the certificate holder in the flight locating procedures, until the completion of the flight.

Each certificate holder shall furnish the representative of the Administrator assigned to it with a copy of its flight locating procedures and any changes or additions, unless those procedures are included in a manual required under this part.