As used in this subpart:
DPFI formula fare means the trunk coach formula fare on July 1, 1977, as established by the Board in Phase 9 of the Domestic Passenger Fares Investigation (Docket 21866-9).
SIFL means the standard industry fare level, as set forth in Sec. 399.31. [PS-92, 45 FR 24118, Apr. 9, 1980]