Transmit proposed flight plans which fall within an ARTCC’s Proposed Boundary Crossing Time (PBCT) parameter to adjacent ARTCC’s via the Computer B network during hours of inter-center computer operation. In addition, when the route of flight of any proposed flight plan exceeds 20 elements external to the originating ARTCC’s area, NADIN must be used to forward the data to all affected centers.
During nonautomated operation, the proposed flight plans must be sent via NADIN to the other centers involved when any of the following conditions are met:
The route of flight external to the originating center’s area consists of 10 or more elements and the flight will enter 3 or more other center areas.
NOTE: An element is defined as either a fix or route as specified in FAA Order JO 7110.10, Flight Services, para 6-3-3, IFR Flight Plan Control Messages.
The route of flight beyond the first point of exit from the originating center’s area consists of 10 or more elements, which are primarily fixes described in fix-radial-distance or latitude/longitude format, regardless of the number of other center areas entered.
The flight plan remarks are too lengthy for interphone transmission.