14 CFR 271.8 - Rate period.
(a) The subsidy rate generally will be set for a 2-year period, or two consecutive 1-year periods. The Department may set the rate for a shorter period in the following situations:
(1) A commuter air carrier is replacing a larger certificated carrier at the eligible place;
(2) Traffic at the eligible place has substantially decreased;
(3) The Department considers the cost or revenue projections of the carrier for the second year to be unrealistic;
(5) The uncertainties of the market or other circumstances warrant a shorter rate period.
(b) The subsidy rate established for a carrier under this part will not be changed during the rate period unless an adjustment is required in the public interest.