What Is In A Dispatch Release In Part 121?

A dispatch release is a legal document containing the plan and details to conduct a flight. Signing a dispatch release is a confirmation between the dispatcher and pilot in command (PIC) that the flight follows all the regulations and is able to safety fly to the destination airport. 

Under § 121.687 the minimum needed for domestic and flag are:

• Identification number of the aircraft
• Trip number
• Departure airport, intermediate stops, destination airports, and alternate airports
• A statement of the type of operation (e.g., IFR, VFR)
• Minimum fuel supply
• For each flight dispatched as an ETOPS flight, the ETOPS diversion time for which the flight is dispatched.
• All current and forecast weather information for all airports listed

Under §121.689 the minimum need for supplemental are:

• Company or organization name
• Make, model, and registration number of the aircraft being used.
• Flight or trip number, and date of flight.
• Name of each flight crewmember, flight attendant, and pilot designated as pilot in command.
• Departure airport, destination airports, alternate airports, and route.
• Minimum fuel supply (in gallons or pounds).
• A statement of the type of operation (e.g., IFR, VFR).
• For each flight released as an ETOPS flight, the ETOPS diversion time for which the flight is released.
• All current and forecast weather information for all airports listed

Supplemental flights are not called dispatch release but rather a flight release, since it is not required for a supplement operation to have a dispatcher. The pilot in command and the director of operations have joint responsibility in conducting a supplement operation.